2.2.1 Psychological Continuity

In an influential contribution to the contemporary debate on the adequacy of human rights protection of our brains and minds, Ienca and Andorno make a case for reinforcing this protection, through the creation of specific “neurorights”.Footnote ⁸ Among other things, they argue for recognising a right to psychological continuity, as “a special neuro-focused instance of the right to identity”.Footnote ⁹ Part of their motivation for arguing this is that emerging neurotechnologies that stimulate and modulate human brain functions – such as tDCS, TMS and DBS – have the potential, in their words, to “cause alterations in mental states critical to personality (…) thereby affecting an individual’s personal identity”.Footnote ¹⁰ Some of these brain stimulation techniques are currently used in day-to-day clinical practice, for example, to treat neurological disorders such as Parkinson’s disease and epilepsy.Footnote ¹¹ Moreover, as mentioned in the introductory chapter, researchers are increasingly examining the potentials of brain stimulation beyond the context of standard medical care, including their use to reduce aggressiveness in forensic populations.Footnote ¹²

Ienca and Andorno highlight that changing a person’s brain functioning through brain stimulation “may have an impact on the psychological continuity of the person, i.e. the crucial requirement of personal identity consisting in experiencing oneself as persisting through time as the same person”.Footnote ¹³ They substantiate this claim by referring to reports of the experience of different kinds of self-estrangement after or during treatment with DBS or following implantation of a BCI.Footnote ¹⁴ Some patients reported, for instance, that BCI implantation “made me a different person”,Footnote ¹⁵ or that DBS treatment (in this case, for Parkinson’s disease) made them “feel like a machine”, reporting that “I’ve lost my passion. I don’t recognize myself anymore”.Footnote ¹⁶ Ienca and Andorno also cite studies that demonstrate that some individuals experience significant mental and behavioural changes as side effects following DBS – for example, increases in impulsivity and aggression, or changes in sexual behaviour – that may, in turn, and depending on the individual, cause them to experience self-estrangement and feel disassociated from themselves.Footnote ¹⁷

Ienca and Andorno’s claim that we ought to recognise a right to psychological continuity is also motivated by the expectation that the advent of brain stimulation techniques may open up possibilities for third parties to induce non-consensual personality changes. Brain implants like DBS bear the risk of being hacked by third parties aiming to exert malicious control over the user’s brain activity.Footnote ¹⁸ Furthermore, in some contexts (e.g., the military and criminal justice), we can anticipate that brain stimulation might be administered on a mandatory basis, given that mandated undertakings are a frequent feature of these contexts. Ienca and Andorno thus argue for the recognition of a right to psychological continuity in order to protect persons against the potentially adverse effects non-consensual brain stimulation might have on their identity. They understand this right as “ultimately tend[ing] to preserve personal identity and the coherence of the individual’s behaviour from non-consensual modification by third parties. It protects the continuity across a person’s habitual thoughts, preferences, and choices by protecting the underlying neural functioning”.Footnote ¹⁹

The idea of developing a right to psychological continuity to protect personal identity from unsolicited (neurotechnological) interferences by others has been picked up on by human rights treaty bodies, both in Europe and internationally. For example, in November 2019, the Council of Europe launched a Strategic Action Plan on Human Rights and Technologies in Biomedicine (2020–2025). One of the plan’s concrete action points is to assess the relevance and sufficiency of existing human rights in view of emerging threats posed by neurotechnology, including threats to personhood and psychological continuity. This plan noted the need to assess “whether new human rights pertaining to cognitive liberty, mental privacy, and mental integrity and psychological continuity, need to be entertained in order to govern neurotechnologies”.Footnote ²⁰A report commissioned by the Committee on Bioethics of the Council of Europe furthermore claims that a human right to psychological continuity would “offer solid normative ground to (…) preserve a person’s self-determination and sense of personal identity from subconscious manipulation”.Footnote ²¹ This report further adds that a right to psychological continuity “may become particularly important in the context of national security and military research, where neurotechnology applications that modulate personality traits (e.g., neurostimulation techniques) are currently being tested for combatant enhancement”.Footnote ²² Other human rights bodies have noted the nature of the concern that some neurotechnologies might pose to psychological continuity, as it is characterised by Ienca and Andorno. In their 2024 report on neurotechnology and human rights, the Advisory Committee of the UN Human Rights Council highlights that “[p]atients having undergone deep brain stimulation have reported feeling a changed sense of agency and identity; thus, ensuring ‘psychological continuity’ may be important”.Footnote ²³

We have been referring to “psychological continuity” as though the concept is widely known and understood. But while the concept of “psychological continuity” is familiar to ethicists and philosophers, it is not commonly invoked in human rights law. As Ienca explains, the concept is borrowed from a specific philosophical understanding of personal identity found in psychological-continuity views.Footnote ²⁴ One such view has been developed by John Locke. In developing his view, Locke’s focus is on accounting for what preserves numerical identity,Footnote ²⁵ or the persistence of a single entity over time.Footnote ²⁶ Numerical identity concerns whether, for instance, Norah at the age of forty (time t₂) is the same person as Norah at the age of twenty (time t₁). Scholars often address this question by referring to the physical or psychological relations that obtain between the relevant entities at t₁ and t₂. Locke’s account of personal identity appeals to a specific psychological relation. It appeals to the idea of “sameness of consciousness” – that is, that a person at time t₁ remains the same person at time t₂ if and only if they share the same consciousness at these two times.Footnote ²⁷ Locke is admittedly unclear about what sharing the same consciousness means. But his remark that “for as far as any intelligent Being can repeat the Idea of any past Action with the same consciousness it had of it at first (…) so far it is the same personal self”Footnote ²⁸ has led some to conclude that, by sharing the same consciousness, Locke means remembering.Footnote ²⁹ As Shoemaker phrases it, on one interpretation of Locke, “a person – a moral agent – Y at t₂ is identical to a person X at t₁ when Y’s consciousness ‘can be extended backwards’ to X, and this is typically taken to mean that YremembersX’s thoughts and experiences”.Footnote ³⁰

The idea that a person remains the same person if and only if they remember their earlier thoughts and experiences has faced various objections. One objection is that it produces some logically impossible results. To illustrate, take the case of an elderly man who remembers the events of his middle years while forgetting the events his physical self experienced in its youth, and suppose that, when in his middle years, the middle-aged man remembered the events of his youth. Here, we have a situation where – if persistence of the self consists in remembering or sameness of consciousness – the youth is the same person as the middle-aged man, the middle-aged man the same as the elderly man, but the youth is not the same person as the elderly man, and this cannot possibly obtain. Assuming that identity is transitive, we cannot logically have A being equal to B, and B being equal to C, without A also being equal to C.

A prominent contemporary approach to avoiding this objection involves amending Locke’s account such that memory plays a less central role in the preservation of identity across time, and other mental features such as intentions, goals, beliefs, desires and similarity of character also assume significance.Footnote ³¹ Arguably, the most influential psychological-continuity account that so amends the Lockean view has been developed by Derek Parfit.

Parfit argues that for X and Y to be the same person at different times, there must be an overlapping chain of enough – that is, strong – psychological connectedness between X today and Y sometime in the past or future.Footnote ³² So, for Norah to be the same person as the Norah that inhabited her body twenty years ago, she must have a sufficient number of overlapping psychological features like desires, beliefs and intentions that persisted from each day to the next over these twenty years. Such an overlapping chain of strong psychological connectedness across time is what Parfit calls psychological continuity; and for Parfit, such strong connectedness exists “if the number of connections, over any day, is at least half the number of direct connections that hold, over every day, in the lives of nearly every actual person”.Footnote ³³ Hence, if a person loses over half the psychological connections one has to themselves – when compared to the connections that obtain within other persons – psychological continuity, and hence numerical identity, will be disrupted, and a different person will come to exist. Note that numerical identity is binary: either the person continues or ceases to exist; either the person keeps or loses their identity.

A psychological-continuity account of identity has enjoyed majority support in philosophy.Footnote ³⁴ It has also been widely invoked in the ethical literature on brain stimulation techniques.Footnote ³⁵ Scholars in this literature raise the same concern as Ienca and Andorno about these techniques, again drawing on empirical data to motivate the idea that brain stimulation has the potential to disrupt psychological continuity. For example, Holmen argues that some mental features central to psychological continuity – desires, beliefs and memories – seem already malleable through both pharmaceutical and neurotechnological means, and if changes to these features were effected in a “sweeping” or sudden and widespread manner, then we would have a disruption of numerical identity.Footnote ³⁶ In the same vein, Vincent claims that there are “non-insignificant grounds to worry that direct brain interventions which implement large-scale changes in one fell swoop could sever psychological continuity”, highlighting that “mounting empirical evidence substantiates the worry that direct brain interventions might have adverse effects on such things as authenticity and personal identity by significantly altering character and personality”.Footnote ³⁷

Klaming and Haselager also conclude that brain stimulation techniques, specifically DBS, could disrupt psychological continuity and identity.Footnote ³⁸ They discuss a study involving a patient who underwent DBS that successfully treated his Tourette’s syndrome but who, twelve months following implantation of the DBS device, developed a dissociative response under certain stimulation amplitudes, wherein he seemed disconnected from himself and his identity.Footnote ³⁹ The patient developed an alternate, childish identity state when the amplitude of the brain stimulation increased. Yet, when the amplitude of the stimulation decreased again, the patient’s responses returned to “normal” and he was unable to recall what had happened during the increased stimulation of his brain.Footnote ⁴⁰ According to Klaming and Haselager, this case “demonstrates that DBS can impinge on psychological continuity (in this case by having profound effects on behavior and memory) and influence an individual’s personal identity to such an extent that an alternate personality state can be observed”.Footnote ⁴¹

Meanwhile, others have challenged the idea that neurotechnological brain stimulation would plausibly induce such global and radical effects on a person’s psychological connections so as to disrupt psychological continuity.Footnote ⁴² For example, Pugh stresses that Parfit’s psychological continuity account implies a high threshold and that “whilst ruptures to numerical identity may be evinced by severe neurodegenerative diseases like Alzheimer’s, persons can also lose a considerable number of psychological connections whilst retaining numerical identity with a future person”.Footnote ⁴³ Against this backdrop, Pugh considers it implausible that DBS treatment would disrupt a patient’s psychological continuity, as there is “little evidence to suggest DBS would typically have global effects on patients’ psychological economies of the sort that would threaten a sufficient number of psychological connections for this to be the case”.Footnote ⁴⁴

We suggest that Pugh’s point has heightened relevance in situations where non-invasive brain stimulation is used to modulate behaviour and reduce a convicted person’s risk of recidivism. Intervention in these sorts of cases can be expected to be highly targeted and appears to lack severe side effects. Present studies focus on the use of tDCS for reducing aggression, delivering a low current to a specific brain region via electrodes on the scull for about twenty minutes.Footnote ⁴⁵ The use of brain stimulation in this context does not appear to induce a global and radical effect on the person’s psychological functioning.Footnote ⁴⁶ Rather, it produces a targeted stimulation of a specific brain area associated with specific behavioural inclinations, such as reducing aggression. Thus far, studies on the use of tDCS for this purpose have not reported any severe psychological side effects. As Knehans et al. write in their literature review on tDCS for reducing aggressive behaviour,

Given the targeted nature of this type of non-invasive brain stimulation and the absence of (severe) psychological side effects in its trial use thus far, it is difficult to envisage how such an intervention could destroy over half of the psychological connections a person holds to themselves compared to a normal, actual person. Consequently, it is hard to imagine that reducing a person’s aggressive tendencies in this way will interfere with the person’s numerical identity such that the person ceases to exist. Of course, we cannot exclude the possibility that wrongful application or misuse of the technology might result in less targeted outcomes for criminal justice populations. We also cannot discount the possibility that unforeseeable side effects might occur even with targeted stimulation, such that severe psychological alterations may ensue in some cases. Nonetheless, if used as intended – that is, to target specific brain areas and specific, justice-relevant behavioural inclinations – the changes induced by brain stimulation within criminal justice contexts are unlikely to meet Parfit’s threshold for disrupting psychological continuity and destroying numerical identity. Instead, the psychological changes are likely to be more “subtle”.

Yet, it still seems as though eroding or destroying merely some psychological connections – for instance, by inducing changes to a person’s intentions, goals, beliefs, desires and character – may diminish or impingeon psychological continuity and/or identity in a way that raises normative concerns. At one level, the case of a person who retains numerical identity, but who has fewer psychological connections with their earlier (same) self after a neurointervention, may raise an issue under the right to mental or psychological integrity (discussed in Chapter 3). At another, having fewer psychological connections with one’s earlier self may still affect identity in other ethically and legally relevant ways, even if it does not affect Parfitian psychological continuity or numerical identity. Some have argued that concerns about brain stimulation and personal identity might be better articulated within the alternative conceptualisation of narrative identity.Footnote ⁴⁸ We consider this line of thought in the following section.

2.2.2 Narrative Identity

Marya Schechtman offers an alternative understanding of personal identity, which she argues can explain, unlike the psychological continuity account, why personal identity matters in the first place – that is, explaining our intuitions about the relation between personal identity and survival, moral responsibility, self-interested concern and compensation.Footnote ⁴⁹ She develops a narrative self-constitution view of identity, according to which persons create their own identity by creating a coherent, autobiographical narrative: a story of their life.Footnote ⁵⁰

Narrative identity, Schechtman explains, is not an answer to what she calls the “reidentification question”: the question of whether two entities at different times are one and the same entity (which Parfit and Locke are concerned with, and which we have previously referred to as numerical identity). Rather, it is an answer to the “characterization question”: the question of which actions, experiences, values, beliefs, character traits – that is, “characteristics” – can be attributed to a given person. This characterisation question concerns the kind of identity that is at stake when people have an identity crisis, looking in the mirror and asking themselves: “Who am I really?”. Questions that come under the umbrella of the characterisation question, Schechtman writes, are those that ask “which characteristics are truly those of some person (as opposed, say, to those which are his as a result of hypnosis, brainwashing, or some other form of coercion)”.Footnote ⁵¹ Schechtman, then, describes the core of narrative identity as follows:

As this quotation clarifies, what determines a person’s identity within this approach largely depends on how the person experiences themselves. It is about how people process their experiences into a coherent, autobiographical story of their lives.Footnote ⁵³ This is not to say that just any random or unrealistic story people tell or believe about themselves determines who they are.Footnote ⁵⁴ Not all narratives are identity-constituting, and Schechtman identifies some general constraints on precisely which kinds of narrative are, the two most important constraints being the (1) articulation constraint and (2) reality constraint.Footnote ⁵⁵

The articulation constraint requires that for shaping and retaining narrative identity, the person (the narrator) should be able to explain why they do what they do, feel what they feel and believe what they believe.Footnote ⁵⁶ To quote from Schechtman, a person should be able “to articulate both the basic features of her history and life situation – the facts of her autobiography – and the way in which her life hangs together, providing explanations for why she has acted as she has and why things have unfolded as they have”.Footnote ⁵⁷ Elements of a person’s narrative that they cannot articulate are still theirs, according to Schechtman. But they are “less fully” theirs, playing a different role in the person’s life compared to articulated aspects of their self-narrative. They are “less attributable” to the person.Footnote ⁵⁸

The reality constraint requires that an identity-constituting self-narrative fundamentally coheres with reality. A person’s self-narrative need not be completely accurate. It may and will contain (trivial) errors and inaccuracies, such as distortions and misremembering of facts. It must, however, “exhibit a fundamental grasp of what the world is like”.Footnote ⁵⁹ This is because personhood, in the sense Schechtman is concerned with, requires being able to engage in activities and interactions with others, and this in turn requires fundamental agreement on the most basic features of reality.Footnote ⁶⁰ Views, beliefs and other characteristics that arise from profound delusions are ruled out as genuinely identity-constituting aspects of a person’s narrative. As Schechtman clarifies, this “does not force us to conclude that psychotics are not persons – rather it allows us to dismiss the elements of psychotic’s narratives that are out of touch with reality, and to recognize that their delusions interfere with personhood and diminish it”.Footnote ⁶¹

Both these constraints illustrate a general feature of Schechtman’s narrative identity: that it admits of degrees.Footnote ⁶² Characteristics that the person cannot explain are to be considered less fully theirs and are less attributable to that person. Gross errors of fact or interpretive inaccuracies will, moreover, diminish personhood. On Schechtman’s view, “when a narrative is disrupted or discontinuous, the degree of identity is correspondingly decreased”.Footnote ⁶³ Identities are thus inherently dynamic, as individuals constantly change and evolve, while making sense of themselves by reconciling these changes into a coherent self-narrative.Footnote ⁶⁴ Changes in narrative identity are consequently not necessarily problematic in and of themselves – people will always change in many different ways throughout their lives.Footnote ⁶⁵

As narrative identity is concerned with how people process their subjective experiences into a coherent, self-told story, this account seems well-equipped to capture (some of the) normative concerns regarding neurotechnology and personal identity. After all, most of these concerns reference the way people experience the acute or long-term (side) effects of neurotechnological brain stimulation, such as subjective experiences of self-estrangement.Footnote ⁶⁶ Recall how persons have reported no longer feeling like themselves following DBS treatment – with some asserting statements like, “Now I feel like a machine, I’ve lost my passion. I don’t recognize myself anymore”; “I feel like a robot”; “I feel like an electronic doll”; “I haven’t found myself again after the operation”, as well as patients perceiving sudden improvements after DBS as “my second birth”.Footnote ⁶⁷ Considering examples like these, Ienca and Andorno highlight that “people’s perception of their own identity may be put at risk by inadequate uses of emerging neurotechnology” and that changing a person’s brain functioning with brain stimulation may impact on “the crucial requirement of personal identity consisting in experiencing oneself as persisting though time as the same person”.Footnote ⁶⁸ As the Advisory Committee of the Human Rights Council put it: DBS patients “have reported feeling a changed sense of agency and identity”.Footnote ⁶⁹ On the face of it, these concerns seem to relate more to narrative identity than to psychological continuity.

After all, within the narrative self-constitution view of identity, Holmen explains, the relevant question is whether the effect of a neurointervention is a threat to the narratives that individuals construct about themselves.Footnote ⁷⁰ Hence, when brain stimulation disrupts these narratives, by inducing an abrupt and radical change in how the person perceives, experiences or feels (about) themselves, it may possibly interfere with narrative identity.

Schechtman herself sees the narrative view as a particularly useful framework in relation to psychological changes induced by DBS.Footnote ⁷¹ She argues that the acute changes sometimes experienced in this regard

Recalling the articulation constraint, such abrupt and radical changes require an explanation. However, in cases of neurointervention, these changes are caused by direct stimulation of the brain as opposed to developing naturally from a person’s intentions, beliefs, desires, emotions, values and plans. There is thus a prima facie tension with the articulation constraint, as a person subject to direct modification of the brain might not be able to articulate just why they now hold a certain attitude or desire – that is, they might not be able to identify the reasons justifying their holding such an attitude, or account for why they endorse it – even if they can detail that they adopted this attitude following DBS. Moreover, if the person in such a case came up with a story telling that the changes are a result of personal development, rather than of DBS, they would run afoul of the reality constraint, as such a self-narrative would be inconsistent with the basic, observable features of reality.Footnote ⁷³

Furthermore, apart from acute psychological changes, Schechtman argues that the long-term effects of brain stimulation could sometimes interfere with narrative identity too. Patients who report adjustment problems following such treatment often have difficulty perceiving their lives as the continuation of the life they were living before. They must reinvent themselves. As Schechtman puts it: “The metaphor of ‘second birth,’ while it can signify new beginnings, also signifies the loss of one’s old identity.”Footnote ⁷⁴

However, considering DBS to treat patients with Parkinson’s disease, Baylis thinks it is unclear why a patient cannot satisfy the articulation constraint by including their consent to DBS in the patient’s self-narrative.Footnote ⁷⁵ What matters for narrative identity is whether personal events and experiences can be integrated into an identity-constituting narrative. Patients suffering from mental or neurological conditions may have good reasons to choose DBS treatment, which in and of itself affects their story and contributes to the dynamic and continuously evolving self-narrative. Hence, psychological changes induced by consented DBS need not diminish one’s narrative identity by failing the articulation or reality constraint. Rather, they may well fit within the person’s story, for example, of a patient combatting depression without success so far and who decides to try DBS. The abrupt and long-term changes induced by DBS, then, could be understood as caused by the patient’s “desire to rid themselves of depression and their willingness to be treated in this way to do so”, as Schechtman herself puts it.Footnote ⁷⁶

This can be different, though, when changes in the person’s self-narrative result from force or oppression rather than free choice.Footnote ⁷⁷ Unlike in cases of consent, when a person is forced to live according to constraints set by others who have fixed ideas about who the person is and who they should become, that person may no longer be able to contribute actively to authoring their own lives in a way consistent with their own interests, values, beliefs, desires and other personal characteristics.Footnote ⁷⁸

This could be particularly relevant to the use of brain stimulation in the context of criminal justice. This context is, in and of itself, coercive. Hardly anyone finds themselves in prison or forensic psychiatry out of free choice. Although convicted persons retain the possibility of making free choices, for example, to participate in a certain treatment or research study, the coercive context of criminal justice may affect the voluntariness of such decisions in some cases, which could, in turn, render the person’s informed consent invalid.Footnote ⁷⁹

In the context of criminal justice, inducing abrupt psychological change by neurointervention, such as tDCS to reduce aggressiveness or sexual drive, without valid consent, seems to be a clear case of contravening the articulation constraint and could, therefore, diminish narrative identity. Obviously, the persuasiveness of this claim largely depends on the precise effects of the neurointervention in question. But we think it plausible that at least some types of neurointervention might have significant impact on the subject’s self-narrative by altering personal characteristics (apart from possible side effects). One could think of a person convicted of assault, who experiences aggressive tendencies and outbursts since their adolescence, in fact, perceiving themselves as the aggressive “hothead” who always runs into trouble. When tDCS induces a significant and acute alteration of these aggressive characteristics in the absence of valid informed consent, the person’s self-narrative will likely be disrupted, thereby threatening the person’s narrative identity.

Whether such disruptions of a person’s self-narrative will eventually affect their identity may, however, also depend on the person’s long-term self-narrative, how neurointerventions are administered and the kind of support offered to the person receiving them. As Schechtman stresses regarding the clinical use of consensual DBS,

From a long-term narrative perspective, she argues, changes that “may look like a narrative break, up close, can be seen as a small segment of a continuous and self-expressive life narrative”.Footnote ⁸¹

Regarding neurointerventions in criminal justice, one can imagine a convicted person who has been trying to reduce their aggressive outbursts and to rehabilitate themselves for years without success. Whereas they tried cognitive behavioural therapy and are willing to take medication, if available, to become less aggressive, the idea of electrical stimulation of their brain frightens them. Therefore, they do, initially, not consent to treatment with tDCS. However, they are informed by the prison staff that consenting to this treatment could increase the likelihood of their being granted parole. Feeling forced, they eventually participate in tDCS. Ultimately, the intervention significantly reduces the person’s aggressiveness and facilitates their successful social rehabilitation, something with which they are very happy. Or alternatively, consider that the person in this scenario is willing to try a tDCS treatment and does voluntarily submit to it, but that their consent is invalid because the information provided to them – such as about risks and (side) effects – is insufficient.

Perhaps, in these scenarios, the non-consensual neurointervention need not ipso facto diminish narrative identity, if the induced psychological changes ultimately fit within the person’s broader narrative of transforming their old “criminal life” towards a new “crime-free life”. Although the neurointervention might induce abrupt psychological changes in the absence of valid consent, these changes may still cohere with the person’s broader aspiration and earlier efforts to attain successful rehabilitation, and may actually contribute to their attaining this personal goal – fitting within the person’s self-expressive life narrative (e.g., getting rid of aggressive tendencies that have been too strong to control). Offering the appropriate support throughout the process of neurorehabilitation may prove essential in this regard, to enable the person to conceive of their life after neurotechnological treatment as a continuation of their life before the intervention.

As such, consent need not be the defining factor that determines whether neurostimulation threatens the person’s narrative identity. Still, there might be cases where nonconsensual neurointerventions in a forensic context will not cohere with the person’s self-narrative and, therefore, interfere with narrative identity. If that is the case, we have the question: Would such an interference be morally problematic?

Interfering with narrative identity in criminal justice seems all but unique for neurotechnology. Being convicted for committing a criminal offence – especially the first time – may already have profound effects on the person’s self-narrative, as will the execution of criminal sanctions, such as imprisonment.Footnote ⁸² As Hardie-Bick writes, “[a]lthough there are many lifecourse transitions that produce disequilibrium and require some form of readjustment, there are few transitions as difficult and demanding as adapting to life behind bars”.Footnote ⁸³ According to Ryberg, few (if any) theorists will accept the so-called “deep freeze view” on imprisonment – the view that assumes convicted persons remain totally unaffected by periods of incarceration.Footnote ⁸⁴

For example, studies have reported that those imprisoned frequently have (potentially) traumatic experiences, for example, due to violence often occurring in prison.Footnote ⁸⁵ More generally, Cunha et al. highlight that imprisonment can be inherently damaging to mental health for a variety of reasons, including the “consequent disconnection from family, society, and social support, loss of autonomy, diminished meaning and purpose of life, fear of victimization, increased boredom, the unpredictability of surroundings, overcrowding and punitiveness, experiencing and witnessing violence, negative staff-prisoner interaction, and other aversive experiences”.Footnote ⁸⁶

Apart from a wide range of damaging (psychological) effects, imprisonment can also change people’s narratives positively. Drawing on interviews with former detainees, Maier and Ricciardelli write that “their narratives speak how imprisonment, by providing distinct space and time for reflection, functioned as a “hook” for self-change and the adoption of new narratives”.Footnote ⁸⁷ The key self-changes during imprisonment reported by the interviewees include “learning patience and being calmer; developing a drug-free narrative; realizing greater appreciation for loved ones; and gaining insights into their personal role in the path that led them to their incarceration”.Footnote ⁸⁸

In fact, in criminal justice, we aim to trigger and induce narrative, mental and behavioural changes all the time, deploying different methods that range from deterrence and (solitary) confinement to mandatory resocialisation programmes, cognitive behavioural therapy, psychiatric treatment and the administration of psychotropic drugs including antipsychotics and antilibidinal medication.Footnote ⁸⁹ Moreover, changing people’s narratives and personal characteristics “for the better” – such as through reformation or correction – is arguably one of the primary objectives of imprisonment (in combination with rehabilitative/treatment programmes) and forensic commitment.Footnote ⁹⁰ Often, these measures aim at getting the robber to stop robbing, the alcoholic to stop drinking and those with aggressive tendencies to reduce and control them. As Article 10(3) of the International Covenant on Civil and Political Rights (ICCPR) prescribes: “[t]he penalty system shall comprise treatment of prisoners the essential aim of which shall be their reformation and social rehabilitation”.

Still, despite these intended and unintended changes in the convicted person’s self-narrative through traditional criminal sanctions (both “positive” and “negative”), incarceration and forensic treatment are not typically conceived of as being wrong for interfering with people’s personal identity. Non-consensual interferences that may lead to changes in identity in this sense are often considered justified, for instance, to punish and to prevent harm to others. Against this background, we agree with Ryberg that it is difficult to reject the non-consensual use of neurointerventions solely on the grounds of personality changes and frustrating the person’s experiences and self-awareness, while at the same time accepting and adhering to the use of incarceration as a form of punishment.Footnote ⁹¹ Interestingly, a recent study on public attitudes towards incarceration and “neuronormalization” showed that the participants (n = 248) “were more supportive of neuronormalization and considered it more ethical” than incarceration. Also, they “considered neuronormalization to be a weaker form of mind control than incarceration and would lead to more change for the better”.Footnote ⁹²

2.3.1 Introduction

As mentioned earlier, neurotechnologies that enable others to modify a person’s mental processes – thereby, potentially interfering with their identity – have raised concerns in view of human rights. Three questions are relevant here: (i) does human rights law protect personal identity?, (ii) if so, to what extent? and (iii) what are the implications of this protection for the use of neurointerventions in criminal justice?

With respect to the first question, protecting people’s personality and identity has a profound basis in human rights law. Article 22 of the Universal Declaration of Human Rights safeguards some essential conditions for dignity and the free development of personality. Article 8 of the United Nations Convention on the Rights of the Child recognises children’s right to preserve their identity. And in the European context, Article 1 of the Oviedo Convention (a legally binding instrument on human rights in the biomedical field) prescribes that the parties “shall protect the dignity and identity of all human beings”.

Elsewhere, a right to identity is indirectly protected. In the Inter-American context, it is implicit in the right to privacy of Article 11 of the American Convention on Human Rights (ACHR).Footnote ⁹³ The same applies to the right to privacy pursuant to Article 17 ICCPR, supporting the protection of the individual’s identity and self-autonomy.Footnote ⁹⁴ The Human Rights Committee has repeatedly emphasised “that the notion of privacy refers to the sphere of a person’s life in which he or she can freely express his or her identity, be it by entering into relationships with others or alone”.Footnote ⁹⁵ The United Nations High Commissioner for Human Rights similarly recognises that “[t]he right to privacy is an expression of human dignity and is linked to the protection of human autonomy and personal identity”.Footnote ⁹⁶ Elaborating on the connection between privacy and identity, Nowak/Schabas write, “privacy protects the special, individual qualities of human existence, a person’s manner of appearance, his or her identity. Identity includes, in addition to one’s name, appearance, clothing, hair and beard style, gender, genetic code, feelings and thoughts, specific past, as well as religious belief and other convictions”.Footnote ⁹⁷

In the European context, the ECtHR likewise considers the notion of private life in the meaning of Article 8 ECHR to encompass a “right to identity” and a “right to personal development”, in terms of either personality or personal autonomy.Footnote ⁹⁸ The protection of personal identity makes many appearances in the case law of the ECtHR,Footnote ⁹⁹ ranging from the protection of gender, genetic and biological identity,Footnote ¹⁰⁰ and also ethnic and religious identity,Footnote ¹⁰¹ to the protection of social and national identity.Footnote ¹⁰² Marshall observes that the case law of the ECtHR reflects, in general, a kind of self-determined and fluid version of identity and personal freedom.Footnote ¹⁰³ It acknowledges “the importance of building and retaining an ability and capacity that is each person’s domain, to enable them to think reflectively without interference, to be in control of their own faculties, to decide their own plan of life”.Footnote ¹⁰⁴

Marshall unpacks the protection of two general conditions of identity formation in the ECtHR’s case law: that is, the protection of our minds and bodies.Footnote ¹⁰⁵ These conditions link closely to the normative concerns voiced in the literature about neurotechnology and personal identity. As discussed in section 2.2, those concerns relate to the ability of neurotechnology to induce significant changes in a person’s brain (body) and mental states (mind) – which according to some could disrupt psychological continuity, while according to others are better understood as a potential interference with narrative identity. The extent to which existing human rights protect both psychological continuity and narrative identity, and the implications of this protection for the neurorehabilitation of convicted persons, is discussed in the following sections.Footnote ¹⁰⁶

2.3.2 Psychological Continuity

To what extent do human rights protect psychological continuity? Elsewhere, one of us has argued that interference with psychological continuity in the Parfitian sense is likely to infringe (1) the right to identity and (2) the right to personal integrity, both protected under Article 8 ECHR and, to some extent, Article 3 ECHR.Footnote ¹⁰⁷ In this section, we reflect on these rights, also in view of the ICCPR.

2.3.3 Narrative Identity

Let us now turn to the protection of narrative identity. To what extent is the way people experience themselves and process those experiences into a coherent, autobiographical story, protected by human rights law? And what might such legal protections imply for the neurorehabilitation of convicted persons?

Protecting and ensuring certain enabling preconditions for the construction of one’s own narrative identity appears to be subject to human rights law, in particular to the right to respect for private life – though the term “narrative identity” is not mentioned in the relevant case law and scholarly literature.Footnote ¹³⁵ Marshall highlights that human rights can be vital “in allowing identity formation, through creating the social conditions to enable an individual to develop their personality and identity as they wish”.Footnote ¹³⁶ The idea of identity formation also has affinities with the idea of narrative construction, giving the “authoring” suggested by both. Marshall stresses that freedom as self-direction and self-development is not something individuals sustain and develop on their own in isolation from the outside world. Rather, the development and preservation of identity partly takes place in relation and conversation with others, within the social environments we find ourselves in.Footnote ¹³⁷ Think of how the right to freely develop, change and adhere to a certain religion or belief, and to manifest one’s religious identity – for example, through dress or going to church – is protected by the right to freedom of religion and belief.Footnote ¹³⁸ Consider, too, how access to information about one’s originsFootnote ¹³⁹ and the preservation of objects of ancestral significanceFootnote ¹⁴⁰ have each been considered to potentially be significant for identity formation and self-development and hence subject to human rights protectionFootnote ¹⁴¹ – and also how these factors seem to pertain to narrative identity specifically.

With respect to access to information about one’s origins, the Glover Report on Reproductive Technologies for the European Commission noted that “our sense of who we are is bound up with the story we tell about ourselves. A life where the biological parents are unknown is like a novel with the first chapter missing”.Footnote ¹⁴² Such a missing chapter may frustrate the person’s ability to answer the characterisation question central to narrative identity: “Who am I really?” The importance of having access to information about one’s origins for identity formation is acknowledged by the ECtHR. In cases on paternity dispute, for example, the Court observed that people “have a vital interest, protected by the Convention, in receiving the information necessary to uncover the truth about an important aspect of their personal identity”.Footnote ¹⁴³ It further observed that respect for private life in the meaning of Article 8 ECHR “requires that everyone should be able to establish details of their identity as individual human beings”, with the individual’s entitlement to such information being “of importance because of its formative implications for his or her personality”.Footnote ¹⁴⁴

With respect to the preservation of objects of ancestral significance, the Human Rights Committee in the case of Hopu and Bessert v. France interpreted the protection of identity under Article 17 ICCPR as sometimes covering the protection of objects that people see as connecting them with their ancestors. In this case, the applicants, both ethnic Polynesians, complained that the construction of a luxury hotel on the site of their ancestral burial grounds would arbitrarily interfere with their privacy in violation of Article 17 ICCPR, because these burial grounds have an important place in their history, culture and life. The Human Rights Committee noted that it “transpires from the authors’ claims that they consider the relationship to their ancestors to be an essential element of their identity”. The majority agreed and concluded that there had been an arbitrary interference with Article 17 ICCPR.Footnote ¹⁴⁵ Because the applicants in this case perceived the relationship to their ancestors as significant to, or even constitutive of, their identity, human rights protection of identity applied.

Although there may be no direct link between these cases and narrative identity, the examples illustrate that for the human rights protection of people’s identity, personal narratives matter at least sometimes. They indicate that at least some aspects of a person’s narrative, and some enabling preconditions for answering the characterisation question, receive protection by the human right to personal identity as part of the rights to privacy and private life. As pointed out earlier, according to Schechtman, the most familiar examples of the characterisation question are “questions of which characteristics are truly those of some person (as opposed, say, to those which are his as a result of hypnosis, brainwashing, or some other form of coercion)”.Footnote ¹⁴⁶ Altering personal characteristics and behavioural traits through neurotechnology has the potential to impact on how persons experience themselves – especially when this takes places without valid – free and informed – consent (section 2.2.2). It appears safe to say that even more than receiving information about one’s origins or the intactness of historic sites and cultural heritage, a person’s unmanipulated brain and mental states – memories, in particular, as the psychological “equivalent” of ancient sites – are important, enabling preconditions for narrative identity formation. If the former are protected through the right to identity, then there is reason to think that the latter should be too.

Furthermore, the self-constitution and formation of personal identity may also be covered by the more general protection of self-determination,Footnote ¹⁴⁷ also enshrined in Articles 8 ECHR and Article 17 ICCPR. For example, regarding Article 17 ICCPR, Nowak/Schabas note that “privacy covers the area of individual autonomy in which human beings strive to achieve self-realization”, which “liberty of action” is “inherent in private self-determination”.Footnote ¹⁴⁸ Taylor speaks in this context of human rights that protect the individual’s “identity and self-autonomy”, including in the dimensions of gender, sexuality and religion.Footnote ¹⁴⁹ In the jurisprudence of the ECtHR, self-determination is closely linked to the notion of personal autonomy,Footnote ¹⁵⁰ the latter being an important principle underlying the interpretation of Article 8 ECHR.Footnote ¹⁵¹ According to the Grand Chamber of the ECtHR, “a right to self-determination” can be derived from the umbrella right to respect for private life pursuant to Article 8 ECHR.Footnote ¹⁵² Among other things, it embraces a right to “informational self-determination” and a right to “sexual self-determination”.Footnote ¹⁵³ Although the ECtHR has not yet clearly articulated the meaning and scope of the right to self-determination, the right protects at least some aspects of a person’s identity.Footnote ¹⁵⁴

This follows most evidently from the case law on sexual orientation and gender identity. According to the ECtHR, gender identity and sexual orientation are one of the most intimate aspects of private life,Footnote ¹⁵⁵ qualifying the latter as “an essentially private manifestation of human personality”.Footnote ¹⁵⁶ The right to self-determination not only protects from interference with private sexual behaviour but also guarantees a freedom to self-create, reshape and develop different aspects of the person’s (sexual) identity, for instance, by defining oneself as either a male or female. As the Court puts it:

The Human Rights Committee has approached the freedom to define one’s own sexual identity as part of the protection of a person’s identity and gender identity under Article 17 ICCPR. For example, the complaint in G. v. Australia concerned an Australian law that did not allow a transgender person to change the reference to her sex on the birth certificate unless she divorced from her spouse (with whom she had a happy relationship). The Human Rights Committee stressed that the right to privacy of Article 17 ICCPR includes the protection of the person’s identity and gender identity and found the Australian law to constitute an arbitrary interference with the person’s privacy and family life.Footnote ¹⁵⁸ Nowak/Schabas note that identity often manifests itself in official documents, such as birth certificates.Footnote ¹⁵⁹ Such pieces of information and official reference can play an important role in the development of people’s narratives and, therefore, in the self-constitution of their identity.

Considering the case law on gender identity and sexual orientation, Marshall observes that the Court’s conception of “freedom” under Article 8 ECHR could be interpreted as “self-creation or self-determination”, protecting the freedom to be and become the person one chooses, “in keeping with their own sense of their identity in a self-determining sense”.Footnote ¹⁶⁰ The right to personal identity in this context allows individuals to freely change, develop and create their identities, “rather than bringing to realisation some essence within”.Footnote ¹⁶¹ As such, personal identity as protected under Article 8 ECHR is flexible and dynamic, rather than fixed and static. As Judge Martens phrased it in a dissenting opinion dating back to 1990, “[h]uman dignity and human freedom imply that a man should be free to shape himself and his fate in the way that he deems best fits his personality”.Footnote ¹⁶²

This shaping of the self can take different forms, one of them being the processing of our personal experiences into a coherent, autobiographical story of our lives. Such a self-determining interpretation of human freedom in relation to personal identity fits well within the general view that the right to respect for private life “secures to the individual a sphere within which he can freely pursue the development and fulfilment of his personality”.Footnote ¹⁶³ If this self-creating and self-determining freedom is interfered with by brain stimulation that disrupts a person’s self-narrative, for example, in the context of neurorehabilitation, the right to self-determination, including the freedom to define one’s own identity, will likely be infringed.

2.3.4 Implications for Neurorehabilitation

Human rights protect personal identity. Meanwhile, many of the concepts referred to in this context, such as identity, personality and mental stability, are still ill-defined in the law.Footnote ¹⁶⁴ In addition, the theoretical underpinnings of the human rights protection of identity are, by and large, undefined and, thus, unclear. Contrary to philosophy, in human rights law, personal identity lacks clear conceptual consideration. The protection of identity appears to develop ad hoc, through individual cases and complaints and is, therefore, fragmented and specified to the facts of those cases. At best, scholars can interpret individual cases and decisions and relate them to specific theoretical accounts of identity, or defend a specific account they think is most appropriate to substantiate a human right to identity.Footnote ¹⁶⁵

We showed that under the ICCPR and ECHR, there is no explicit recognition of either Parfit’s psychological continuity or Schechtman’s narrative identity account. However, as argued in the previous section, there are reasons to assume that, implicitly, these types of identity receive protection from human rights. Interference with both narrative identity and psychological continuity may sometimes infringe the rights to identity and self-determination, which are inherent in the right to privacy. Disrupting a person’s psychological continuity may furthermore infringe the right to personal integrity.

Let us for now assume that, to some extent, both psychological continuity and narrative identity receive protection within the established framework of human rights, in particular through the right to identity inherent in the right to privacy/private life.Footnote ¹⁶⁶ Let us also assume that in some cases the use of brain stimulation for the rehabilitation of convicted persons can infringe the right to identity. Then, the next question is whether and under what conditions such an infringement could be justified, or whether certain neurotechnological interferences with the identity of convicted persons will be prohibited across the board.

As the protection of identity is part of the qualified right to privacy, it is subject to limitations. Both under Article 17 ICCPR and 8 ECHR, infringements of the right to privacy can be justified when having a (non-arbitrary) legal basis and being proportionate to a legitimate aim, such as the prevention of crime and the protection of the rights and freedoms of others.Footnote ¹⁶⁷ For example, some types of non-consensual medical interventions, such as taking blood for DNA analysis, infringe the right to private life under Article 8 ECHR, but can still be justified for obtaining evidence of the person’s involvement in the commission of a criminal offence.Footnote ¹⁶⁸ Furthermore, non-consensual medical treatment, which would normally infringe the right to respect for private life, could be justified in case of “medical necessity”.Footnote ¹⁶⁹ Whether and when interference with a convicted person’s identity through a neurointervention could be justified is hard to predict. This will depend on a range of factors that vary across individual cases, such as the induced neural, psychological and behavioural changes, and the purpose of the intervention, for example, whether it is employed for medical reasons or to prevent severe or less severe crimes.

Here, we will not estimate which types of identity change caused by neurointerventions may or may not be permissible under different conditions. Rather, we wish to highlight a more general feature of identity interference that emerges, specifically, from the ECtHR case law – which may inform our thinking about the (im)permissibility of identity-affecting neurointerventions in criminal justice more broadly. This particularity relates to the margin of appreciation doctrine developed in the jurisprudence of the ECtHR.

In determining whether an infringement of the right to respect for private life is proportionate to the legitimate aim it pursues, the national authorities enjoy a margin of appreciation, which can either be “wide”, “certain” or “narrow”.Footnote ¹⁷⁰ The narrower this margin, the stricter the ECtHR’s review of the proportionality of a rights infringement.Footnote ¹⁷¹ The broader this margin, the more discretion states enjoy in striking a “fair balance” between the competing personal and public interests at stake.Footnote ¹⁷² The breadth of this margin of appreciation varies across individual cases and depends on a number of relevant factors,Footnote ¹⁷³ such as the context of the interference and the level of consensus among the member states of the Council of Europe, either as to the relative importance of the interest at issue or as to the best way of protecting it.Footnote ¹⁷⁴

Another relevant factor concerns the importance of the right at stake. In principle, the margin of appreciation will be narrow when the “essence” or “core” of a convention right is affected. Gerards explains this approach from the perspective of effective protection of the ECHR in relation to the principle of subsidiarity: the more important a right, the more reason for supervision on how that right is guaranteed on the national level.Footnote ¹⁷⁵ The ECtHR has identified four central values underlying the ECHR: democracy and the rule of law, pluralism, human dignity, and personal autonomy. According to Gerards,

Under Article 8 ECHR, the ECtHR has repeatedly stated that when “a particularly important facet of an individual’s existence or identity is at stake, the margin allowed to the State will be restricted”.Footnote ¹⁷⁷ For example, in a case on the legal recognition of a parent-child relationship after surrogacy, the ECtHR held that “regard should also be had to the fact that an essential aspect of the identity of individuals is at stake where the legal parent-child relationship is concerned. The margin of appreciation afforded to the respondent State in the present case therefore needs to be reduced”.Footnote ¹⁷⁸ In another case, the ECtHR explained that the “extent of the State’s margin of appreciation depends not only on the right or rights concerned but also, as regards each right, on the very nature of the interest concerned. The Court considers that the right to an identity (…) is an integral part of the notion of private life. In such cases, particularly rigorous scrutiny is called for when weighing up the competing interests”.Footnote ¹⁷⁹

In the same vein, when the non-consensual stimulation of a convicted person’s brain changes personal characteristics that are to be considered an essential aspect of the person’s identity – which we conceive as plausible in at least some cases (section 2.2) – the margin of appreciation will most likely be narrow too. In those cases, the national authorities have less discretion in balancing the convicted person’s private interests against the public interest of crime prevention (e.g., by lowering recidivism risks). Consequently, the ECtHR could then apply a strict test of necessity and proportionality, critically assessing the availability of less intrusive means, and may require additional procedural safeguards in domestic law to guarantee careful and individualised decision-making and access to judicial remedies.Footnote ¹⁸⁰

3.2.1 The Right to Security of Person

Looking first to the right to personal security pursuant to Article 9 ICCPR, it is clear that both bodily and mental integrity are protected. According to General Comment No. 35, this right “concerns freedom from injury to the body and the mind, or bodily and mental integrity”.Footnote ¹⁰ It protects individuals “against intentional infliction of bodily or mental injury” but also against “foreseeable threats” to the same.Footnote ¹¹ Physical and mental integrity in this context are understood quite narrowly: infringements require at least some kind of physical or mental injury, which we can understand as physical or mental harm or damage.Footnote ¹² ‘Injury’ under Article 9 ICCPR is understood as denoting only harms or damage that pass a certain level of severity. The above mentioned General Comment stipulates that “the right to security of person does not address all risks to physical or mental health”.Footnote ¹³ This Comment also specifically refers to violent behaviours when discussing security of the person.Footnote ¹⁴

A wide range of actions can, however, still pass this threshold of severity. Think of a gunshot wound, a death threat or an assassination attempt.Footnote ¹⁵ Deep brain stimulation (DBS) also plausibly causes physical injury in the sense required for Article 9 ICCPR, in that it requires surgery for the implantation of electrodes in a person’s brain – which involves making a small hole in the skull and placing a neurostimulator under the collarbone. Consequently, if performed in the absence of valid consent, this physical injury caused by DBS could infringe Article 9 ICCPR. Whether DBS also inflicts mental harm or injury is less clear. This probably depends on the precise stimulation and its accompanied (side) effects. But insofar as the placement of electrodes in a person’s brain is non-consensual, it seems plausible that undergoing such a procedure could in and of itself be mentally distressing in a way that infringes Article 9 ICCPR, on at least some occasions.Footnote ¹⁶

Non-invasive interventions such as tDCS and TMS, on the other hand, seem less likely to infringe the right to security of the person by causing physical or mental injury, though infringements are not impossible. The direct physical side effects of these interventions are minor, such as causing itchiness and a tingling sensation.Footnote ¹⁷ The intended mental effects, meanwhile, may be substantial, such as reducing depression, aggressiveness or increasing emphatic abilities. However, in our view, such mental effects can hardly be considered mental injury of the kind protected under Article 9 ICCPR. We say this because the abovementioned mental effects are not obviously antithetical to mental/psychological health or well-being, or detrimental to a person’s mental or cognitive capacities – features that we might expect to be required for something to constitute a mental injury. That said, we cannot rule out the possibility of mental injury even with these non-invasive approaches. If delivered non-consensually, these interventions may cause mental distress in at least some circumstances, particularly if the recipient failed to identify with the mental changes these techniques brought about.Footnote ¹⁸ There is also the possibility of unforeseen, harmful side effects with tDCS and TMS, as with DBS.

3.2.2 Privacy Rights

The scope of the protection of personal integrity by the right to privacy (Article 17 ICCPR) and the right to respect for private life (Article 8 ECHR) is arguably broader, in that these rights also seem to protect against actions that can be expected to induce smaller physical or mental changes, without the necessary requirement of causing physical or mental injury.Footnote ¹⁹ Regarding Article 17 ICCPR, Nowak/Schabas write that the right to privacy covers “the protection of personal integrity”, which, for example, is at stake in cases of body searches, withdrawal of blood samples, non-consensual medical treatments, national prohibitions of pregnancy termination, intentional trivial insults by executive organs and minor quarrels.Footnote ²⁰ Although these interventions could all potentially cause minor physical or mental harm, in most of these examples, severe bodily or mental injury seems unlikely or at least is not foreseeable.Footnote ²¹ Infringements of personal integrity under Article 17 ICCPR thus do not seem to be limited to actions that induce severe bodily or mental injury.

The ECtHR has explicitly stated that the right to respect for private life pursuant to Article 8 ECHR “provides for the protection of physical and mental integrity”.Footnote ²² For the interpretation of these Article 8 guarantees, the ECtHR considers personal autonomy an “important principle”.Footnote ²³ The right to physical integrity under Article 8 ECHR covers a variety of severe and less severe interferences with the body, ranging from minor non-consensual medical interventions, such as taking saliva with a buccal swabFootnote ²⁴ and withdrawing blood samples,Footnote ²⁵ to more serious interferences, including forced medication,Footnote ²⁶ strip searchesFootnote ²⁷ and gynaecological examination in prison.Footnote ²⁸ The right to mental integrity, also referred to as “psychological” and “moral” integrity,Footnote ²⁹ is associated with the protection of mental health.Footnote ³⁰ But its protective scope is arguably broader,Footnote ³¹ as the right also pertains to bullying at school,Footnote ³² well-founded fear for physical abuse,Footnote ³³ and loss of honour and reputation, for example, by others publishing defamatory statements and erotic pictures of a person in the media.Footnote ³⁴

Still, application of the right to mental integrity specifically in court cases is yet relatively scarce. Consequently, much remains unclear about the right’s meaning and scope under Article 8 ECHR. For example, it is unsettled whether the infliction of mental harm or distress is required for infringing the right; or whether the right also covers interferences that do not directly harm mental well-being (such as making a person happier through secretly administering antidepressants, or changing their preferences or beliefs through subliminal advertising).

One guiding point is that Article 8 ECHR applies when the effects of an interference on personal integrity are “sufficiently adverse”.Footnote ³⁵ As De Vries explains, “Article 8 only applies when a person’s physical or psychological integrity is adversely affected to a certain degree. Thus, the obligation to wear a seatbelt does not come within the scope of the right to private life.”Footnote ³⁶ Yet, this jurisprudential criterion is still vague and has not been further developed in case law yet.Footnote ³⁷ What does the ECtHR mean by adverse effects? Would making people happier, less aggressive or more emphatic qualify as such? And when are the effects of an interference sufficiently adverse so as to infringe the right to personal integrity?

Regarding bodily integrity, many interferences seem to meet this ‘sufficiently adverse’ requirement: “even a minor interference with the physical integrity of an individual must be regarded as an interference with the right to respect for private life under Article 8 if it is carried out against the individual’s will”.Footnote ³⁸ Taking a buccal swab, for instance, infringes the right to bodily integrity under Article 8 ECHR if performed non-consensually, although it “is an act of a very short duration, it usually causes no bodily injury or any physical or mental suffering, and thus is of minor importance”.Footnote ³⁹ Mandatory x-ray for tuberculosis screening and the obligation of imprisoned persons to provide a urine sample for drug testing also infringe this right.Footnote ⁴⁰ Furthermore, regarding medical treatment, Harris et al. write that without consent such treatment raises serious issues within the scope of private life, “however slight the intervention”.Footnote ⁴¹ Apparently, “slight” interferences with the body that are “of minor importance” can still qualify as “sufficient” and thus infringe the right to bodily integrity. Perhaps the implicit reasoning behind this is that non-consensual bodily interference, although minor, reduces the person’s control over their body, thus interfering with personal autonomy in that regard, which is, as said, an important principle underlying the interpretation of Article 8 ECHR.

Non-consensual brain stimulation thus may infringe the right to bodily integrity as protected by the right to privacy and private life, even if the physical effects of the intervention are minor (as they would likely be in the case of tDCS or TMS).Footnote ⁴² We say “may infringe” because clearly not all bodily interferences of minor significance infringe this right. We often cause non-consensual yet minor effects in other people’s bodies that cannot plausibly be held to infringe the right to bodily integrity – for instance, tapping someone on the shoulder, raising the room temperature significantlyFootnote ⁴³ or telling a disgusting story that causes one to wretch or vomit.Footnote ⁴⁴ Yet, given that the case law pertaining to the right to bodily integrity under Article 8 ECHR and Article 17 ICCPR indicates that (very) minor bodily interferences performed non-consensually (e.g., mandatory x-ray and the obligation to provide urine samples) can infringe the right, it is not too far of a stretch to expect human rights courts to find non-invasive, non-consensual brain stimulation to infringe the right to bodily integrity too. DBS would certainly be judged to infringe this right, given that, as said, the physical interference involved in DBS is significant.

Still, that the right to bodily integrity is infringed need not imply that the right is violated. Recall that the right to privacy (Article 17 ICCPR) and the right to respect for private life (Article 8 ECHR) are qualified rights. Infringements can be justified when, generally speaking,Footnote ⁴⁵ they have an accessible and foreseeable legal basis, pursue a legitimate purpose – such as preventing crime and disorder – and are proportionate in relation to that purpose.Footnote ⁴⁶ The slightness of a bodily interference through non-invasive brain stimulation is legally significant here, particularly with regard to the requirement of proportionality.

In general, the more severe an infringement of a human right, the more substantial the reasons must be to justify such an infringement.Footnote ⁴⁷ Conversely, less intrusive interferences require less weighty reasons for their justification. Minor bodily interference caused by non-invasive brain stimulation thus can plausibly be held proportionate for the prevention of serious criminal offences – including abuse, murder and rape – even if they infringe the qualified right to bodily integrity. Many criminal justice practices that interfere with the body (e.g., handcuffing and strip searches) are not typically conceived of as violating the right to bodily integrity as they aim to prevent harm to others and can therefore be justified.Footnote ⁴⁸ Sometimes even more severe bodily effects are considered proportionate to prevent harm, at least in some jurisdictions (for instance, the oft-severe physical effects and side effects of antilibidinal medication), though this is controversial.Footnote ⁴⁹ Moreover, although the Human Rights Committee was “concerned at the lack of clarity on the frequency and circumstances surrounding the use of coercive electroconvulsive treatment” in Norwegian mental health-care institutions, it did not rule out the permissible use of these coercive interventions, concluding that Norway “should increase procedural safeguards for patients and stipulate in law the circumstances allowing for the limited use of coercive electroconvulsive treatment”.Footnote ⁵⁰

Does this mean that the right to personal integrity under Articles 17 ICCPR and 8 ECHR only offers weak protection against non-invasive brain stimulation? Not necessarily. While the bodily interference might be of minor gravity, the mental interference may – at least in some instances – be much more severe.Footnote ⁵¹ As Bublitz stresses, what really matters are the mental effects of brain stimulation, encompassed by the right to mental integrity.Footnote ⁵² Likewise, according to Craig, “there are strong reasons to believe that the most compelling arguments against non-consensual [direct brain interventions] do not rest on the right to bodily integrity, but on the more fundamental right to ‘mental integrity’”.Footnote ⁵³

As said, the right to mental integrity as covered by the abovementioned privacy rights is relatively underdeveloped. We therefore do not yet have the legal resources to assess whether the right to mental integrity might afford persons greater protection against non-consensual brain stimulation than that which is afforded by the right to bodily integrity, under Articles 17 ICCPR and 8 ECHR. Nonetheless, if the scope of the right to mental integrity turns out to be analogous to the scope of the right to bodily integrity under these provisions – that is, as a right against sufficiently adverse effects on the mind – neurointerventions that alter mental states or processes may be considered to regularly infringe the right to mental integrity.Footnote ⁵⁴ We delve deeper into this issue in section 3.3, discussing three different approaches to further construct the protective scope of the right to mental integrity, and consider some of their implications for the right’s permissible limitations.

3.2.3 The Prohibition of Torture, Inhuman, and Degrading Treatment

On top of the qualified protection offered by the right to personal integrity pursuant to Articles 17 ICCPR and 8 ECHR, some severe interferences with physical and mental integrity could also breach the absolute and non-derrogable prohibition of torture, inhuman and degrading treatment and punishment. Nowak/Schabas equate the prohibition of torture of Article 7 ICCPR with “the right to physical and spiritual integrity”.Footnote ⁵⁵ In the General Comment on Article 7 ICCPR, the Human Rights Committee clarifies that the aim of this provision “is to protect both the dignity and the physical and mental integrity of the individual” and that it “relates not only to acts that cause physical pain but also to acts that cause mental suffering”.Footnote ⁵⁶ The ICCPR does not provide a clear definition of the concepts covered by Article 7 ICCPR, “nor does the [Human Rights] Committee consider it necessary to draw up a list of prohibited acts or to establish sharp distinctions between the different kinds of punishment or treatment”.Footnote ⁵⁷ In general, the distinction between torture, cruel, inhuman and degrading treatment and punishment depends on the nature, purpose and severity of the treatment inflicted.Footnote ⁵⁸ The assessment of what constitutes inhuman or degrading treatment as prohibited by Article 7 ICCPR “depends on all the circumstances of the case, such as the duration and manner of the treatment, its physical or mental effects as well as the sex, age and state of health of the victim”.Footnote ⁵⁹

The same applies mutatis mutandis to the prohibition of torture, inhuman and degrading treatment of Article 3 ECHR, which prohibits, in absolute terms, serious interferences with bodily and mental integrity,Footnote ⁶⁰ ranging from the intentional infliction of severe physical and mental suffering (i.e., torture) to treatment that arouses feelings of fear, anguish and inferiority, capable of humiliating and debasing the person (i.e., degrading treatment).Footnote ⁶¹ To infringe – and therefore violate – Article 3 ECHR, treatment or punishment must attain a “minimum level of severity”.Footnote ⁶² Whereas the prohibition of ill-treatment is itself absolute, this severity threshold is relative. It depends on all the circumstances of the individual case, including the nature and context of the treatment, the manner and method of its execution, its duration, its purpose, its physical or mental effects and, sometimes, the sex, age and state of health of the victim and their vulnerable status.Footnote ⁶³

No doubt the surgical implantation of electrodes in a person’s brain to control some of their brain processes will, without valid consent, qualify as inhuman or degrading treatment (and perhaps even torture). Such practices are likely prohibited across the board by Articles 7 ICCPR and 3 ECHR. Meanwhile, regarding non-invasive neurointerventions, including tDCS and TMS, the relevance of the absolute prohibition of ill-treatment is plausibly far more limited.Footnote ⁶⁴ After all – provided that these interventions are safe and effective – their application should not typically cause bodily injury, physical pain or mental suffering. Rather, they are of short duration and may influence mental features, such as empathic abilities, through minor and painless bodily alterations (an effect that future technologies may have). These ‘subtle’ interferences with the body and mind are, in and of themselves, unlikely to attain the severity threshold of the prohibition of ill-treatment.Footnote ⁶⁵ They are plausibly not severe enough to elicit the absolute protection of physical and mental integrity from Articles 7 ICCPR and 3 ECHR.

However, next to physical and mental integrity, the prohibition of ill-treatment also aims to protect human dignity. Regarding Article 3 ECHR, Harris et al. observe that for “degrading treatment” the emphasis is on humiliation and debasement, rather than on physical and mental suffering.Footnote ⁶⁶ According to the ECtHR there is a strong link between respect for human dignity and the concept of “degrading” treatment.Footnote ⁶⁷ The latter being defined sometimes as treatment that “humiliates or debases an individual, showing a lack of respect for, or diminishing, his or her human dignity, or when it arouses feelings of fear, anguish or inferiority capable of breaking an individual’s moral and physical resistance”.Footnote ⁶⁸ At the international level, the protection of human dignity by Article 7 ICCPRFootnote ⁶⁹ is complemented by the right of detainees to be treated with humanity and dignity pursuant to Article 10 ICCPR.Footnote ⁷⁰ In human rights law, human dignity features different understandings, including “inherent dignity” – that is, the worth of every person by virtue of being a human.Footnote ⁷¹ One core aspect of human dignity is the care for and protection of human beings as subjects and as specific individuals with personality.Footnote ⁷²

Subjecting a convicted person to brain stimulation in order to change their behaviour by modifying their neural and mental functioning could be argued to reduce the person to an object rather than a subject, which disrespects human dignity and could therefore violate the legal norms laid down in Articles 7, 10 ICCPR and 3 ECHR.Footnote ⁷³ The ECtHR, in Tyrer/UK – a case about the infliction of corporal punishment by the police – considered that treating a person as an object could indeed interfere with human dignity, stating that

One way of objectifying persons, Bublitz argues, is by reducing them to their corporal existence, to their bodies, such as through “reductive forms of neuroscience which seek to explain and address mental aspects exclusively at the level of the brain”.Footnote ⁷⁵

If we follow this line of thought, the use of non-consensual brain stimulation to induce behavioural change in convicted persons can at least in some situations raise concerns about human dignity. For example, this could be the case when forensic behavioural interventions would exclusively operate through modifying a convicted person’s brain, purely treating the person as a means, rather than as an end in themselves.Footnote ⁷⁶ Meanwhile, concerns about objectification and disrespecting human dignity may diminish when the use of neurointerventions complements – or is complemented by – rehabilitation programmes that respect subjectivity.Footnote ⁷⁷

Often, rehabilitation programmes in criminal justice entail a wide spectrum of services and activities that engage with the convicted person.Footnote ⁷⁸ These include education, work training, therapy and probation on a variety of conditions, ranging from substance abuse counselling to pharmacological interventions for reducing sexual drive. Embedding non-invasive brain stimulation as a complementary element in such larger and diverse rehabilitation programmes would likely negate or at least diminish concerns about objectification and human dignity.

Interestingly, for a treatment or punishment to violate Article 3 ECHR, the ECtHR holds that the suffering and humiliation involved “must in any event go beyond that inevitable element of suffering or humiliation connected with a given form of legitimate treatment or punishment”,Footnote ⁷⁹ such as imprisonment or, in this context, existing accepted pharmacotherapeutic practices. Regarding present forms of non-invasive brain stimulation, such as tDCS and TMS, we do not see a clear and compelling reason why the suffering or humiliation involved would exceed the level of suffering and humiliation entailed by accepted pharmacological interventions – provided that they are incorporated within a broader rehabilitation programme.

3.2.4 The Right to Freedom of Thought and Freedom of Opinion

Finally, depending on its conceptualisation, mental integrity could also be implicitly protected by the right to freedom of thought and, to some extent, by the right to freedom of opinion. Under Articles 18 ICCPR and 9 ECHR, the right to freedom of thought is generally considered an absolute right.Footnote ⁸⁰ Infringements are never permissible. The same applies to the right to freedom of opinion in the meaning of Article 19 ICCPR.Footnote ⁸¹ Whether the freedom to hold opinions under Article 10 ECHR is also absolute is less clear. Whereas the text of Article 10 ECHR suggests qualified protection, it has been argued that the freedom of opinion in this provision “enjoys an almost absolute protection in the sense that the possible restrictions set forth in paragraph 2 are inapplicable”.Footnote ⁸²

The right to freedom of thought is typically taken to protect against the “impermissible alteration” of thought, thereby protecting some aspects of persons’ “mental autonomy”.Footnote ⁸³ According to the Council of Europe’s Human rights handbooks, the internal dimension of Article 9 ECHR seeks at its most basic level “to prevent state indoctrination of individuals by permitting the holding, development, and refinement and ultimately change of personal thought, conscience and religion”.Footnote ⁸⁴ Vermeulen and Roosmalen write that the internal dimension of Article 9 ECHR guarantees that States may never interfere with the most intimate and inner sphere of their citizens. They are not allowed to dictate what people should believe, nor may they use coercion to make individuals change their beliefs, such as through “brainwashing”.Footnote ⁸⁵ As examples of possible infringements of the right to freedom of thought pursuant to Article 18 ICCPR, the Special Rapporteur on Freedom of Religion or Belief has considered, among other things, psychological torture, re-education of political prisoners, involuntary treatment for mental disorders, non-consensual conversion practices and – interestingly for our present purposes – neurotechnological interventions that alter mental states.Footnote ⁸⁶

An essential element of the right to freedom of opinion is the freedom to form and develop opinions by way of reasoning.Footnote ⁸⁷ It protects the holding of an opinion without interference,Footnote ⁸⁸ which requires among other things freedom from coercion in the development of beliefs, ideologies, reactions and positions.Footnote ⁸⁹ The Special Rapporteur on Freedom of Opinion and Expression writes that violations of Article 19(1) ICCPR could consist in “forced neurological interventions, indoctrination programmes (such as ‘re-education camps’) or threats of violence designed to compel individuals to form particular opinions or change their opinion”.Footnote ⁹⁰

According to Bublitz, taken together, the essence of the rights to freedom of thought and opinion “lies in the protection of the most important mental states, processes, and abilities, i.e. in mental actions such as thinking, reasoning, decision-making, imagining, or remembering, as well as forming and revising of beliefs, opinions, attitudes, and related mental states and processes”.Footnote ⁹¹ Regarding both Articles 18 and 19 ICCPR, Nowak/Schabas consider that they require “[s]tate parties to refrain from interfering with an individual’s spiritual and moral existence – whether this be through indoctrination, ‘brainwashing’, influencing of the conscious or subconscious mind with psychoactive drugs or other means or manipulation”.Footnote ⁹²

In the literature on the human rights implications of neurotechnology, the main focus is on the freedom of thought (rather than the freedom of opinion). Non-consensually modifying mental states and processes through neurointerventions in criminal justice has been argued in the scholarly literature to infringe the absolute right to freedom of thought such that it should be “prohibited across the board”.Footnote ⁹³ The plausibility of this claim, however, very much depends on how one defines the scope of the right,Footnote ⁹⁴ which partly depends, in turn, on how one interprets “thought” in this context – a question that is currently under debate.Footnote ⁹⁵ Roughly, three interpretations can be distinguished.Footnote ⁹⁶

First, according to what we could call the “narrow view”, “thought” under Article 18 ICCPR and Article 9 ECHR is confined to thoughts originating from religion.Footnote ⁹⁷ This narrow understanding does not receive much (if any) support in recent scholarly literature – even if, in past practice, Article 18 ICCPR “had been generally interpreted as safeguarding only the freedom of religion and the freedom of thought and belief associated with religion”.Footnote ⁹⁸

A second position, referred to as the “moderate view”,Footnote ⁹⁹ holds that “thought” denotes especially significant thoughts, with great personal importance.Footnote ¹⁰⁰ On this view, the right to freedom of thought offers absolute protection not to just any thought, opinion, idea or other mental state. Rather, it protects those thoughts that have a major impact on a person’s way of living, including political, cultural, philosophical and scientific thought, and, arguably, a person’s deepest wishes and sexual desires.

According to a third position, referred to as the “robust-scope view”, thought means any mental state with content as well as thinking as a mental process.Footnote ¹⁰¹ On this view, all thoughts and thinking are protected, including political thoughts, a person’s thought to have a cup of coffee, and their thoughts about what colour socks to wear.Footnote ¹⁰²

On the first two positions, brain stimulation for the rehabilitation of convicted persons is unlikely to infringe the right to freedom of thought in most cases, as these interventions do not typically interfere with a person’s religious adherence nor with significant personal conceptions such as their political or philosophical views. There may be an infringement of the right to freedom of thought on the moderate view, however, if an intervention interferes with, for example, sexual desires – insofar and to the extent that a person’s sexual desires are of great personal importance to them.

On the robust-scope view, neurointerventions may more regularly infringe the right, given that this view sees all thoughts as coming under the scope of freedom of thought. So, brain stimulation to change a person’s antisocial attitude towards criminality, for example, would constitute an infringement on this view.Footnote ¹⁰³

Note, however, that also on this view, interference with mental phenomena that are not considered “thoughts” in ordinary language will not reasonably infringe the right.Footnote ¹⁰⁴ One could think of feelings, tendencies, behavioural control, risk taking, empathic abilities and emotional responses – typical targets for the rehabilitation of convicted persons. The general rule of interpretation of Article 31(1) of the Vienna Convention seems to oppose the qualification of such mental phenomena as protected “thoughts”, prescribing that “ordinary meaning” should be given to the terms of a treaty in light of its object and purpose. As Bublitz writes when defending the robust-scope view, “[i]n common usage, ‘thought’ refers to specific mental entities. This meaning must therefore be integrated into the interpretation of Article 18(1) ICCPR”.Footnote ¹⁰⁵ Since mental phenomena such as feelings, behavioural inclinations and emphatic abilities are not normally captured by the common understanding of “thought”, interfering with such mental phenomena through neurotechnology will plausibly fall outside the scope of the right to freedom of thought.

To substantiate a broad interpretation of “thought”, proponents of the robust-scope view often refer to the General Comment on Article 18 ICCPR, highlighting that “[t]he right to freedom of thought (…) is far-reaching and profound; it encompasses freedom of thought on all matters”.Footnote ¹⁰⁶ Furthermore, a recent report on the right to freedom of thought by the UN Special Rapporteur on Freedom of Religion and Belief can be interpreted as endorsing a robust understanding of thought.Footnote ¹⁰⁷

Whereas the robust-scope view gets arguable support regarding the interpretation of Article 18 ICCPR, it appears to lack support with regard to Article 9 ECHR. Rather, the case law on Article 9 ECHR suggests an interpretation along the lines of the moderate view.Footnote ¹⁰⁸ For example, in F.P./Germany, the EComHR considered that Article 9 ECHR “is essentially destined to protect religions or theories on philosophical or ideological universal values”.Footnote ¹⁰⁹ Moreover, the ECtHR’s Grand Chamber has repeatedly considered that, in general,

This means that Article 9 ECHR does not protect just any thought, opinion or idea.Footnote ¹¹¹ To be protected by this provision, personal or collective views must meet a certain threshold, which supports the moderate view.

One could argue that this threshold only applies to the freedom to manifest thought, conscience and religion.Footnote ¹¹² However, this is unlikely for at least two reasons.Footnote ¹¹³ First and foremost, in the above quote the ECtHR clearly refers to Article 9 ECHR, and Article 9 ECHR does not protect external manifestations of thought. The manifestation/expression of thought is instead protected by the right to freedom of expression.Footnote ¹¹⁴ Hence, referring to “thought” in the meaning of Article 9 ECHR can only pertain to unexpressed thought.

Second, the very first sentence of Article 9 ECHR – Everyone has the right to freedom of thought, conscience and religion – is generally taken to comprise forum internum protection.Footnote ¹¹⁵ This right is “largely exercised inside the individual’s heart and mind” and receives absolute protection.Footnote ¹¹⁶ The forum externum protection is encompassed by the addition that “this right includes freedom (…) to manifest his religion or beliefs”.Footnote ¹¹⁷ Hence, if the ECHR refers to “the right to freedom of thought, conscience and religion”, as it does in the quotation above, then this must at least cover forum internum protection. If the ECHR’s consideration on cogency, seriousness, cohesion and importance would only have applied to the forum externum, they would not have referred to the right to “freedom of thought, conscience and religion” but rather to the “freedom to manifest one’s religion or beliefs”.

The ECtHR, admittedly, has provided little guidance on how to understand and apply the threshold requirements of cogency, seriousness, cohesion and importance.Footnote ¹¹⁸ Neither has it applied them in cases concerning the protection of inner “thought”, instead focusing on the manifestation of religion and beliefs. The precise implications of this threshold are thus largely uncertain and we are left to speculate. Nonetheless, some remarks voiced within the United Kingdom’s House of Lords on the matter may prove at least somewhat instructive. In the case of R. (Williamson) v. Secretary of State for Education and Employment, Lord Nicholls observes that, with respect to “seriousness” and “importance”, a manifested view or belief that comes under the protective scope of Article 9 ECHR “must be a belief on a fundamental problem”.Footnote ¹¹⁹ And with respect to “cogency” and “cohesion”, Lord Nicholls observes that these requirements relate to “being intelligible and capable of being understood”, while also emphasising that “being intelligible” is not the same as being “susceptible to (…) rational justification”.Footnote ¹²⁰

These observations arguably only push the problem back, given that we still have to figure out what “a fundamental problem” and “intelligible” mean. But it is plausible that some thoughts, views and beliefs more obviously pertain to fundamental problems – again, philosophical and religious beliefs about how, for example, (one ought) to live one’s life or organise society. Everyday thoughts about the kind of socks to wear or whether to grab a cup of coffee, on the other hand, seem far less likely to do so (and hence seem unlikely to be covered by Article 9 ECHR) – notwithstanding that these thoughts relate in some small way to how the relevant individual chooses to live their life.Footnote ¹²¹

When it comes to mental phenomena that might be relevant targets for neurorehabilitation, such as certain desires or preferences, their relation to fundamental problems is not entirely clear. One perspective, again voiced by Lord Nicholls, might be that these mental phenomena only pertain to fundamental problems if they “relate to an aspect of human life or behaviour of comparable importance to that normally found with religious beliefs”.Footnote ¹²² A similar idea is voiced by Cecile Laborde in her interpretation of the “importance” requirement as being reached when a given thought or belief “actually occupies a pivotal place in [individuals’] lives as they want to live it, and is not simply a peripheral, incidental or occasional commitment”.Footnote ¹²³ These comments suggest that what is at issue is whether a given view is something its bearer strongly identifies with or holds dear.Footnote ¹²⁴

Some desires or predilections that are relevant from a rehabilitation perspective – for example, paedophilic or violent sexual desires – may assume as important a role in a person’s life as their political or religious beliefs. If these kinds of thoughts or desires sometimes assume such importance, then it may be that, on the moderate-scope view, some sexual preferences enjoy absolute protection under Article 9 ECHR.

That said, the mental states and processes typically targeted by neurointerventions for purposes of rehabilitation may often fall short of engaging absolute protection form Article 9 ECHR: either because they do not meet its threshold or because they cannot be considered “thoughts” in the first place (e.g., empathic abilities, behavioural control, risk-taking tendency).

3.2.5 Brief recap

The integrity of the person consists of two elements: the protection of the human body and mind. Grave interferences that cause severe physical or mental suffering can elicit absolute protection from the prohibition of ill-treatment. The same applies to interferences that are humiliating or disrespect human dignity. Regarding the neurorehabilitation of convicted persons, this protection seems especially relevant in relation to invasive forms of brain stimulation, such as DBS. Non-invasive interventions are, by contrast, generally less likely to meet the severity threshold of this absolute prohibition. Still, they could engage absolute protection by infringing the right to freedom of thought. Whether they do, largely depends on how “thought” is defined in the meaning of the right, which is yet unsettled.

The broadest protection against unsolicited bodily and mental interference is offered by the right to privacy and respect for private life, providing qualified protection against severe and less severe interferences with physical and mental integrity. Presumably, the right to bodily integrity will not offer strong protection against non-invasive brain stimulation for rehabilitation purposes, as the bodily interference of these interventions will often be minor. Meanwhile, their mental effects could be significant. Hence, non-invasive brain stimulation may well severely infringe the right to mental integrity. Whether they do not only depends on the mental effects of a specific neurointervention, but also on our understanding of the right to mental integrity, in particular its scope and permissible limitations. In the next section, we explore three possible constructions of the right’s scope and consider some of their implications for the right’s permissible limitations.

3.3.1 Meaning and Scope

While the right to mental integrity has received little attention in the law so far,Footnote ¹²⁵ in philosophical literature, constructing the right is an important topic in discussions concerning the regulation of neurotechnologies.Footnote ¹²⁶ Whereas some philosophers are especially interested in the moral underpinnings of a legal right to mental integrity,Footnote ¹²⁷ others consider the contours and significance of mental integrity as a moral right.Footnote ¹²⁸ We acknowledge that a moral right to mental integrity need not straightforwardly imply nor correspond to its legal counterpart, even though human rights are often considered to reflect moral guarantees. Still, when aiming to construct the meaning and scope of a legal right to mental integrity, the philosophical literature could provide some guidance.Footnote ¹²⁹ In what follows, drawing from both legal and philosophical perspectives, we distinguish three general understandings of a right to mental integrity and consider their suitability for constructing the right within human rights law.Footnote ¹³⁰ Consecutively, we consider the right to mental integrity as (1) a freedom to control mental states and processes, (2) a freedom from direct and harmful mental interference and (3) a freedom from significant mental interference.Footnote ¹³¹

3.3.2 Permissible Limitations

Inducing mental changes in others is not exceptional in our everyday social lives. We do so all the time – in some social domains more than others. One could think of the compulsory education of children, the provision of psychopharmaceuticals to psychiatric patients, and the reformation and rehabilitation of convicted persons. When not consented to, many such mental influences plausibly infringe a right against significant mental interference. However, presumably, not all of them are legally (or morally) impermissible. There could be good reasons for legally allowing the bringing about of mental changes in persons for different purposes in different contexts. Again, one could think of educating children, treating forensic psychiatric patients and rehabilitating convicted persons. But how should the law distinguish permissible from impermissible interferences with mental integrity? As Bublitz writes, “[t]he key challenge for the construction of the right to mental integrity lies in developing a taxonomy that sorts the many examples of everyday and undoubtedly permissible social interactions adversely affecting minds of others (causing disappointment, anger, anxiety, etc.) from the supposedly impermissible ones. The legal criteria for this distinction have not been established”.Footnote ¹⁹³

Developing such a taxonomy would exceed the scope of this book. Meanwhile, as the issue of permissible versus impermissible limitations of the right to mental integrity is essential to the permissibility of neurorehabilitation, we wish to briefly explore the following question here: How should judges determine whether an infringement of the right to mental integrity – understood as a right against non-consensual significant mental interference – would be justified, or whether it would rather violate this right?Footnote ¹⁹⁴

Whether an infringement of the right to mental integrity is also a violation largely depends on an ultimate balancing of the competing interests at stake, which, in turn, will largely depend on the facts and circumstances of the individual case. In the preceding section, we concluded that neither the direct-indirect distinction nor the infliction of physical and/or psychological harm appear decisive factors for determining the scope of the human right to mental integrity. However, we think these factors would be relevant to the question of justification – and, consequently, the possible violation of the right. Let us recall that interferences with a person’s body and mind can infringe the right to personal integrity to different degrees, with different severities. The more severe the infringement, the more substantial the reasons must be to justify such an infringement.Footnote ¹⁹⁵ For example, regarding bodily integrity, non-consensually inserting a needle in a person’s body will less severely infringe the right compared to non-consensually performing surgery, the latter requiring stronger reasons to be justified. The same plausibly applies to mental integrity.Footnote ¹⁹⁶

This is where the direct-indirect distinction and the level of harm become relevant. If the primary aim of a right to mental integrity is to protect autonomy over mental states and processes, then it is plausible that the less mental control an intervention leaves to the affected person, the more severe the infringement of the right to mental integrity is. If we assume that, generally, direct interventions leave less control over mental states than indirect interventions, this will imply that, in general, stronger reasons are needed to justify infringements through direct interventions compared to indirect interventions. From that point of view, Bublitz may be right in saying that interventions that undermine or bypass mental control are “particularly troublesome” – they may be more difficult to justify.

The same applies mutatis mutandis to the issue of psychological harm. When an infringement of the right to mental integrity also entails some kind of (severe) psychological harm, such as stress or depression as a side effect of medication or brain stimulation, it is reasonable to suppose that this will contribute to the severity of the rights infringement, therefore requiring more substantial reasons for justification. Moreover, if the level of harm attains a certain severity threshold, absolute protection from the prohibition of ill-treatment could be engaged (see section 3.2).

What could all this mean for the use of non-consensual neurointerventions in criminal justice? These interventions are of direct nature, such as tDCS, TMS and psychopharmaceuticals. Hence, the mental changes they induce may leave little (if any) room for mental control by the person involved, and as such, they may interfere with the person’s mental autonomy to a significant degree. Therefore, they will likely be considered to severely infringe the right to mental integrity, thus requiring weighty reasons to be justified. The need for such substantial reasons may further increase when the intervention entails harmful psychological side effects. If any such reasons exist, the prevention of severe crimes – such as abuse, rape and murder – is a likely candidate.

Although we think the above analysis makes sense in principle, it is unclear how strict the requirements for justification will be in practice. Recall that the context of criminal punishment and crime prevention allows for a wide range of severe and less severe interferences with both bodily and mental integrity (e.g., strip searches in prison,Footnote ¹⁹⁷ collection of blood samples,Footnote ¹⁹⁸ antilibidinal interventions to sex offendersFootnote ¹⁹⁹). In general, regarding potential violations of Article 8 ECHR – which includes the right to mental integrity – in the context of imprisonment, the ECtHR holds that

This is an important point, which may be used to substantiate at least two different arguments, both in another direction.

First, one could argue that imprisonment, in and of itself, often severely affects the incarcerated person’s well-being and psychological functioning and may have serious impact on a variety of mental phenomena that are protected by the right to mental integrity, such as feelings, emotions, traits and desires. As touched upon earlier in this and the previous chapter, incarceration is notoriously known for its potential negative effects on the persons’ psychological well-being, for example, by the traumatic experiences or mental harm incarceration can cause. Furthermore, research suggests that imprisonment has significant adverse effects on brain areas associated with self-control. Recent studies reported that neuropsychological capacities in incarcerated persons declined after three to four months in prison.Footnote ²⁰¹ Meijers et al. hypothesize that the cause of the decline may be, at least in part, the impoverished prison environment, which is supported by the findings in animal studies (and some studies in humans) on the influence of the environment on brain and behaviour.Footnote ²⁰² Recall, furthermore, that a recent study on the public attitudes towards incarceration and neurointerventions found that the participants considered neurointerventions “to be a weaker form of mind control than incarcerations and would lead to more change for the better”.Footnote ²⁰³

Against this background, one could argue that, if the effects on the mind caused by “normal restrictions and limitations” consequent on lawful incarceration normally do not raise any issues regarding the right to mental integrity, it is unpersuasive to oppose non-consensual neurorehabilitation by appealing to the right to mental integrity – provided that the mental effects are either of similar gravity or less severe compared to incarceration.Footnote ²⁰⁴

On the other hand, it can be argued that the mental changes entailed by imprisonment differ from those induced through neurointerventions in a way that is normatively significant, and, therefore, that neurointerventions may violate the right to mental integrity while imprisonment would normally not. For example, Birks and Buyx argue that although both neurointerventions and incarceration may involve equal interference with the person’s mental states, harming the person to the same extent in the same respect, “it does not follow that the harm-doing is morally equivalent. There could be a difference in terms of intention between some of the harm-doings caused”.Footnote ²⁰⁵ If intentional harm is harder to justify than unintentional but merely foreseen harm, Birks and Buyx argue, “then this could account for the view that neurointerventions are morally objectionable in one respect that incarceration is not”.Footnote ²⁰⁶ Put differently: mental alterations that are a result of unintended side effects (e.g., of incarceration) are morally less objectionable than intended mental changes of similar intensity, such as those caused by neurointerventions that aim to induce mental change. In the same vein,Footnote ²⁰⁷ Shaw suggests that “intended effects and side effects may lie on a spectrum, and the closer the mental-integrity-undermining effects of a punishment or neurointervention fall toward the intended end of the spectrum, the harder the punishment or neurointervention may be to justify”.Footnote ²⁰⁸

Intuitively, the idea that unintended interference with mental integrity is less objectionable than intended interference may sound appealing.Footnote ²⁰⁹ However, in our view, the moral or – for the present purpose – legal significance of this distinction strongly depends on conceptualisation of (the right to) mental integrity that one follows. Birks and Buyx understand the “interest in mental integrity” as “a person’s interest in not having at least some of his mental states intentionally altered by others in certain ways”.Footnote ²¹⁰ Likewise, Shaw proposes that the moral right to mental integrity “can be infringed by intentionally interfering with a person’s mental states through nonrational means”.Footnote ²¹¹

Indeed, if the right to mental integrity is understood as a right against some forms of intentional mental interference, the “level of intentionality” is plausibly relevant for determining the severity of the rights infringement, which in turn affects its potential justification. This could mean that knowingly causing mental alterations by sending someone to prison less severely infringes the right to mental integrity than purposely inducing mental change of similar intensity, for example, by brain stimulation. However, if one adopts an understanding of the right to mental integrity that does not include the requirement of intentionality, such as the “right against significant mental interference” we discussed in the previous section, the normative significance of the distinction between intentional versus side effects is at least questionable, also because, typically, to be justified, infringements of the right to mental integrity need to be intentional: they must pursue a ‘legitimate aim’ and be proportionate to that aim, such as the prevention of crime or the protection of the health of others. Moreover, including an “intentionality-requirement” into the scope of the right, may well result in reduced human rights protection against (neuro)interventions that have serious side effects on people’s minds, just because those effects were not intended.

4.2.1 The Right to Privacy

The right to privacy has a robust foundation in human rights law. It is for instance recognised in the Universal Declaration of Human Rights (Article 12), the International Covenant on Civil and Political Rights (Article 17) and the European Convention on Human Rights (Article 8) – with the latter (as earlier indicated) referring to the right to “respect for private life”.

What is meant by a right to privacy? According to the UN Human Rights Council, privacy can be considered “as the presumption that individuals should have an area of autonomous development, interaction and liberty, a ‘private sphere’ with or without interaction with others, free from State intervention and from excessive unsolicited intervention by other uninvited individuals”.Footnote ²¹ Several moral rationales have been advanced as underpinning this right to privacy.Footnote ²² Many scholars emphasise the instrumental value of privacy for enabling freedom and autonomy, with some arguing (more strongly) that without the protection of private life, individual freedom and autonomy would be impossible.Footnote ²³ Other scholars suggest that privacy has non-instrumental value, or value in-and-of-itself, such that in its absence people would fail to flourish.Footnote ²⁴ And still others argue that a right to privacy is justified for respect-based reasons – that is, that refraining from intruding on a person’s privacy is necessary to respect that individual as a person or being “with sensibilities, ends, and aspirations of their own”.Footnote ²⁵

The right to privacy is relevant for our present analysis because obligations to reveal private mental phenomena – for example, using non-consensual brain-reading – are likely to infringe the right to privacy. The right to privacy is, after all, both widely applicable and broad in scope – both in the case of Article 17 ICCPR and Article 8 ECHR. It applies to state agents who might interfere with a person’s privacy. It also requires that states adopt legislative and other measures to give effect to the protection of privacy.Footnote ²⁶ And the right’s breadth means that it should protect against a wide spectrum of privacy interference, including by modern means.

Looking first to the international context, Article 17 ICCPR “is a short but versatile provision, capable of answering a broad diversity of unlawful or arbitrary incursions into privacy (…) which could not have been specifically foreseen by its drafters”.Footnote ²⁷ For example, Article 17 ICCPR applies to AI systems that process personal data for algorithmic decision-making.Footnote ²⁸ It also covers the protection of metadata, as such data, when analysed and aggregated, “may give an insight into an individual’s behaviour, social relationship, private preference and identity”.Footnote ²⁹ Furthermore, the UN High Commissioner for Human Rights, when discussing the right to privacy, refers to data-driven technologies that “increasingly enable States and business enterprises to obtain fine-grained information about people’s lives, make inferences about their physical and mental characteristics and create detailed personality profiles”.Footnote ³⁰ The High Commissioner considers informational privacy to be particularly important in the age of modern technology and digital environments.Footnote ³¹ The High Commissioner also holds that the right to privacy of Article 17 ICCPR is not only impacted by the examination and use of personal data by humans or algorithms. Even the mere generation and collection of data relating to a person’s identity, family or life will affect the right, “as through those steps an individual loses some control over information that could put his or her privacy at risk”.Footnote ³²

In the European context, the ECtHR emphasises that “private life” is a broad concept that does not lend itself to exhaustive definition.Footnote ³³ It is clear though that the right to private life covers the protection of “personal data”. Referring to Article 2 of the Data Protection Convention 1981, the ECtHR defines personal data as “any information that relates to an identified or identifiable individual”.Footnote ³⁴ According to Article 3 of the EU Law Enforcement Directive (2016/680), “personal data” means “any information relating to an identified or identifiable natural person (‘data subject’); (…) such as a name, an identification number, location data, an online identifier or to one or more factors specific to the physical, physiological, genetic, mental, economic, cultural or social identity of that natural person”.Footnote ³⁵

The ECtHR considers the protection of personal data of fundamental importance to the enjoyment of the right to respect for private life and holds that Article 8 ECHR comprises “the right to a form of informational self-determination, allowing individuals to rely on their right to privacy as regards data which, albeit neutral, are collected, processed and disseminated”.Footnote ³⁶ When considering whether personal information relates to someone’s “private life” in the meaning of Article 8 ECHR, and whether the collection, storage or use of that information infringes this right, the ECtHR has due regard to: (1) the nature of the records, (2) the results that may be obtained, (3) the specific context in which the information has been recorded and retained and (4) the way in which these records are used and processed.Footnote ³⁷

Examples of infringements of Article 8 ECHR in the context of criminal justice include taking and retaining a photograph on arrest, yielding fingerprints and cellular samples for DNA analysis, and the collection of personal information via a GPS tracking system.Footnote ³⁸ Plausibly, the right to privacy also applies to the employment of other emerging technologies that yield personal data, including neurotechnological brain-reading such as with fMRI and EEG.Footnote ³⁹ Such brain-reading could moreover produce sensitive personal data, allowing the drawing of inferences about, for example, emotions, sexual orientation and/or mental health.

Given its broad scope, there is reason to suppose that the right to privacy as guaranteed by Articles 17 ICCPR and 8 ECHR also implies a right to mental privacy. It is reasonable to suppose, first, that the ethical values thought to ground a right to privacy – that is, the values of freedom and autonomy, human flourishing, and respect for persons – are crucially advanced by the protection of mental privacy. Think of how a lack of mental privacy would likely limit the freedom and “natural flow” of people’s ideas (and hence actions),Footnote ⁴⁰ and of how some degree of mental seclusion and separation is plausibly necessary for beings like ourselves to function and flourish.Footnote ⁴¹ Second, legally, it is indeed plausible that a right to mental privacy is ipso facto covered by the general right to privacy. As Bublitz argues, it seems evident that the latter established right covers the former: “[s]everal international instruments protect a general right to privacy or private life. According to the standards of legal interpretation, this abstract right implies more context or domain-specific variations. In other words, mental privacy is implied by the more general right to privacy”.Footnote ⁴²

Many lawyers will confirm and endorse this view. For example, already in their seminal article on the right to privacy published in 1890, Warren and Brandeis observed that “the common law secures to each individual the right of determining, originally, to what extent his thoughts, sentiments, and emotions shall be communicated to others”.Footnote ⁴³ This legal protection, they argued, is merely an instance of the general right to be let alone – the right to privacy – which could be invoked to protect against “invasion either by the too enterprising press, the photographer, or the possessor of any other modern device for recording or reproducing scenes and sounds”.Footnote ⁴⁴ Over a century later, the UN Special Rapporteur on the Right to Privacy (Article 17 ICCPR) warned “that constantly developing technologies pose important challenges for the protection of privacy: these technologies may reveal the most intimate behaviour, wishes, preferences and indeed the very thoughts of individuals in ways that previously were not possible”.Footnote ⁴⁵ As the UN Special Rapporteur on Freedom of Religion or Belief highlights, in the United States, “courts recognise that an individual right to privacy encompasses mental privacy”.Footnote ⁴⁶ Likewise, in the European legal context, it has been argued that the right to respect for private life pursuant to Article 8 ECHR covers, among many other things, the protection of mental privacy.Footnote ⁴⁷ These observations seem to confirm that a right not to reveal thoughts, emotions, sentiments, preferences, wishes, or other private mental phenomena – a right to mental privacy – is covered by the general right to privacy.Footnote ⁴⁸

Non-consensual neuroprediction arguably infringes the right to privacy,Footnote ⁴⁹ notwithstanding that the right is unlikely to prohibit neuroprediction across the board. Recall that infringements of the right to privacy can be justified under both Article 17 ICCPR and 8 ECHR if they have an non-arbitrary basis in domestic law and are necessary for and proportionate to a legitimate purpose, such as the prevention of crime and disorder.Footnote ⁵⁰ Given that permissible privacy infringements have included, among many other things, secret surveillance and DNA testing for the purpose of preventing crime and protecting the rights of others,Footnote ⁵¹ and legally obliging witnesses to reveal their knowledge and memories about a criminal offence in court,Footnote ⁵² the right to (mental) privacy is unlikely to prohibit, in principle, all non-consensual applications of neuropredictive technologies that reveal private information about brain and mental states for the purpose of preventing crime.Footnote ⁵³ We return to this in section 4.3.

4.2.2 The Right to Freedom of Expression

The secrecy of our mental states and content also receives protection from the right to freedom of expression, guaranteed by Articles 19 ICCPR and 10 ECHR.Footnote ⁵⁴ The relevance of this right to the protection of mental privacy lies in its negative aspect, guaranteeing the freedom not to express oneself. This negative freedom is something we have an interest in possessing. We have an interest in having a “reasonable measure of control” over the ways in which we express and present ourselves to othersFootnote ⁵⁵ – consider how expressing ourselves might sometimes open us up to social scrutiny and potential social harm.

The freedom not to express oneself was clearly emphasised by the European Commission on Human Rights (EComHR) in the case of Strohal/Austria, where the EComHR argued that “the right to freedom of expression by implication also guarantees a ‘negative right’ not to be compelled to express oneself, i.e., to remain silent”.Footnote ⁵⁶ The Grand Chamber of the ECtHR “does not rule out that a negative right to freedom of expression is protected under Article 10 of the Convention, but finds that this issue should be properly addressed in the circumstances of a given case”.Footnote ⁵⁷ Recently, the ECtHR confirmed that the right to freedom of expression has a negative aspect: “A holistic protection of the freedom of expression necessarily encompasses both the right to express ideas and the right to remain silent; otherwise, the right cannot be practical or effective.”Footnote ⁵⁸ Compelling the applicants to express a message with which they disagreed infringed the right’s negative aspect in this case. In the same vein, the General Comment to Article 19 ICCPR states: “Freedom to express one’s opinion necessarily includes freedom not to express one’s opinion.”Footnote ⁵⁹

This is, in our view, a logical implication of the freedom to express oneself, which entails that the expression of opinions, ideas and other information is freely chosen – that one can freely choose between expressing and not expressing oneself. A right not to express opinions, ideas, feelings, knowledge and other kinds of information corresponds, in our view, almost seamlessly to a right to mental privacy – at least, if one understands this right as a right not to reveal unexpressed mental phenomena such as mental states and content.

Apart from few exceptions,Footnote ⁶⁰ the content of an expression is irrelevant to the applicability of the right to freedom of expression.Footnote ⁶¹ Referring to the work of the CCPR, Taylor writes that the freedom of expression protects the dissemination of content “which many, in some cases most, may find unwelcome or repugnant (spanning pornography, offensive art, anti-Semitic messages or messages in support of terrorism)”.Footnote ⁶² Likewise, according to the ECtHR, the right to freedom of expression is “applicable not only to ‘information’ or ‘ideas’ that are favourably received or regarded as inoffensive or as a matter of indifference, but also to those that offend, shock or disturb”.Footnote ⁶³ As such, the scope of the right to freedom of expression is considered “extremely broad”.Footnote ⁶⁴ The logical implication of this is that the negative freedom not to express oneself is broad too.

Interestingly, the right to freedom of expression protects not only the substance of information but also a diverse range of forms and means by which information is expressed, transmitted and received.Footnote ⁶⁵ For example, among many other things, the ECtHR has applied the right to speech, poetry, painting, radio, film, handcuffing oneself to a barrier during protest, disrupting foxhunting by blowing a hunting horn and performing a puppet show satirical of politicians.Footnote ⁶⁶ The General Comment on Article 19 ICCPR mentions spoken, written and sign language, non-verbal expression such as through images, objects of art and dress, and legal submissions.Footnote ⁶⁷

So, both Articles 19 ICCPR and 10 ECHR guarantee a broad right to freedom of expression. They protect opinions, ideas, facts, value statements and other information of almost any content, transmitted through practically any means, which may, in theory, also concern neurotechnological means, such as fMRI, EEG and BCI. Crucially, they also protect the freedom not to express; and given this, the right to freedom of expression likely protects against the obligation to disclose private information, such as mental phenomena, through neuroprediction.Footnote ⁶⁸

Similar to the right to privacy, the right to freedom of expression pursuant to Article 10 ECHR will not prohibit, in principle, the non-consensual use of neuropredictive tools, as the right may be subjected to “formalities, conditions, restrictions or penalties” that have a legal basis and are necessary within a democratic society for the legitimate interest of, among other things, preventing disorder and crime.Footnote ⁶⁹

Note, however, that Article 19 ICCPR distinguishes between, respectively, the right to hold opinions without interference and the freedom to express information and ideas of all kinds. Whereas the latter freedom to express information (including opinions) may be limited, for example for the protection of public order, the former may not: the right to freely hold opinions is an absolute right, not susceptible to restriction or limitation,Footnote ⁷⁰ and this right “includes [the] freedom not to express one’s opinion”.Footnote ⁷¹ Hence, strictly speaking, the protection of mental privacy, in the form of privacy of opinion, is absolute under Article 19 ICCPR. Regarding neuroprediction in criminal justice, the relevance of this absolute component of Article 19 ICCPR will probably be limited. Neuropredictive applications in this domain are likely to reveal information about phenomena such as self-control and emotional processing, and thus hardly qualify as revealing the person’s opinion about something. Infringement of the absolute right to freedom of opinion is, therefore, unlikely. Article 19 ICCPR thus does not necessarily prohibit all non-consensual usage of neuroprediction – provided that such usage does not qualify as compelling persons to express “opinions”.

4.2.3 The Right to Freedom of Thought

The right to freedom of thought, conscience and religion is guaranteed by Articles 18 ICCPR and 9 ECHR, and is often espoused as being central to the enjoyment of other basic rights and liberties, as well as being crucial for democracy.Footnote ⁷² The right is often considered to consist of an internal and external dimension, offering protection within the so-called forum internum and forum externum.Footnote ⁷³ The internal dimension of the right is often considered to be absolute, not permitting “any limitations whatsoever”.Footnote ⁷⁴ It covers the freedom to have, change and adopt a religion, conviction and thought. In the external dimension, the right guarantees the qualified freedom to manifest religion and belief. The manifestation of thought, however, is not protected by the right to freedom of thought pursuant to Articles 18 ICCPR and 9 ECHR. These Articles only protect unmanifested thought. The manifestation of thoughts, such as through speech and expression, is protected by the right to freedom of expression.Footnote ⁷⁵

In the internal, absolute dimension, the right to freedom of thought is generally considered to guarantee three substantive freedoms: (1) that no one is compelled to reveal their thoughts, (2) that one’s thoughts are not impermissibly altered and (3) that no one will be sanctioned for their thoughts.Footnote ⁷⁶ The UN Special Rapporteur on Freedom of Religion or Belief holds that the first freedom implies that mental privacy is a “core attribute” of freedom of thought and also includes, arguably, a right to remain silent.Footnote ⁷⁷ According to the Rapporteur, the freedom not to be compelled to reveal one’s thoughts is currently under threat by, inter alia, neurotechnologies that allow the drawing of inferences about a variety of unexpressed mental states.Footnote ⁷⁸ Likewise, considering the potential of neurotechnological lie detection and memory detection in criminal justice, Bublitz finds it “hard to imagine a better paradigmatic case against which freedom of thought should provide protection”.Footnote ⁷⁹

However, the scope of the mental privacy protection afforded by the right to freedom of thought depends, considerably, on how one interprets “thoughts” in the context of this right. As discussed in Chapter 3, some have argued for a broad interpretation, such that the right protects any mental state with content and thinking as a mental process (robust-scope view).Footnote ⁸⁰ For example, O’Callaghan et al. have argued that thought in the meaning of Articles 18 ICCPR and 9 ECHR “can be understood as encompassing all forms of unmanifested mental activity, including ‘deliberation, imagination, belief, reflection, reasoning, cogitation, remembering, wishing, sensing, questioning, and desiring’”.Footnote ⁸¹ On such an understanding, the freedom not to reveal private “thoughts” comes down to a broad right to mental privacy – that is, a right not to reveal any unexpressed mental state and content. As also discussed in Chapter 3, for the interpretation of the right to freedom of thought pursuant to Article 18 ICCPR, such a robust interpretation receives some support,Footnote ⁸² also from the UN Special Rapporteur on Freedom of Religion or Belief.Footnote ⁸³

Adopting such a broad scope would have profound effects on the human rights protection of mental privacy: if we assume a broad understanding of “thought”, the privacy protection offered by the right to freedom of thought will considerably overlap with both the right to privacy and the right to freedom of expression. All three rights will then imply a right not to reveal unexpressed personal mental states and content. This poses a theoretical difficulty, as the protection of mental privacy by the right to freedom of thought is considered absolute, as opposed to the qualified protection offered by the right to privacy and, in the European context, the freedom of non-expression. This raises the question: How should the law distinguish between the applicability of either absolute or qualified mental privacy protection?Footnote ⁸⁴ The answer to this question will be crucial for the permissibility of interferences with mental privacy, including through non-consensual neuroprediction in criminal justice. We explore this question in the next section.

4.3.1 Characteristics of the Privacy Interference: Means and Targeted Mental Phenomena

A general characteristic of an interference with mental privacy that may be relevant for distinguishing the applicability of the absolute right to freedom of thought from the qualified right to privacy or freedom of expression, relates to the method of revealing personal mental states. Of course, this can be interpreted in different ways, however, as we will explain, we consider this aspect in terms of “control” – more specifically the level of control the employed method leaves to the person whose mental states are being revealed. Regarding interventions that aim to change or modulate a person’s mental states (like neurointerventions), Bublitz has argued that the level of self-control a person retains should be relevant to the applicability of the absolute right to freedom of thought, as infringements of the freedom of thought typically disrespect a person’s control over their own thoughts and thinking. According to Bublitz: “This is a necessary, but not a sufficient condition, and it forms part of a test of infringement: Does an intervention respect the other as a free and self-controlled thinker; or does it undermine or bypass control? The latter infringes freedom of thought, the former may not.”Footnote ¹⁰⁴

A similar line of reasoning may be explored regarding the privacy dimension of the right to freedom of thought.Footnote ¹⁰⁵ One of the dominant approaches to information privacy conceives of privacy as a right to control personal information.Footnote ¹⁰⁶ For example, as Fried argued, “privacy is not simply an absence of information about us in the minds of others; rather it is the control we have over information about ourselves”.Footnote ¹⁰⁷ The emphasis on controlling personal information is also reflected in the law. For instance, under Article 8 ECHR, the ECtHR has recognised a right to “informational self-determination”.Footnote ¹⁰⁸ Furthermore, recital 7 of the European GDPR states firmly that “natural persons should have control of their own personal data”. The value of controlling personal information, including mental states, seems also relevant to mental privacy under the right to freedom of thought. As the drafters of Article 9 ECHR put it, the right to freedom of thought, conscience and religion intends to protect “not only from ‘confessions’ imposed for reasons of State, but also from those abominable methods of police enquiry or judicial process which rob the suspect or accused person of control of his intellectual faculties and of his conscience”.Footnote ¹⁰⁹

It appears generally accepted that within the forum internum the right to freedom of thought is absolute. Hence, absolute human rights protection of mental privacy, one could argue, may at least be warranted regarding means that disclose thoughts directly from the forum internum, that is, means that do not involve any form of expression and conscious control whatsoever, and to which consent is not obtained. An example of such means could be the hacking of a person’s BCI, which seems to destroy the core essence of mental privacy, that is, the person’s ability to control the disclosure and dissemination of private mental content.Footnote ¹¹⁰ Bublitz has argued in the same direction, proposing that the “main condition prompting freedom of thought protection is the revelation of unexpressed thoughts”, which means that “the rightholder has not manifested them through voluntary actions such as speech”.Footnote ¹¹¹ He submits that neuroimaging “does not work through the person as a subject – by coercing or compelling her – but bypasses her as a subject to extract unexpressed thought. This breach of the inner sphere may suffice to reach the required level of seriousness”.Footnote ¹¹²

Following this line of thought, the non-consensual use of neuroimaging for the purpose of risk assessment in criminal justice may, in some instances, be considered to infringe the absolute right to freedom of thought – that is, when they do not involve any form of expression and conscious control whatsoever. However, since identifying relevant mental phenomena, such as certain intentions or inclinations, with neurotechnology will usually require at least some engagement from the person themselves (e.g., performing a task, observing stimuli, not manipulating the assessment), it is questionable whether their non-consensual use can regularly be considered to completely bypass or undermine the person’s mental control.

Another relevant characteristic of mental privacy interference that could contribute to determining the “seriousness” of the interference relates to the precise mental phenomenon that is targeted and revealed. The significance of a person’s interests in not revealing information about certain types of mental states and content may be important.Footnote ¹¹³ For example, there may be good reasons to assume that the significance of the interest in not revealing one’s political or religious ideas could justify absolute protection from the freedom of thought.Footnote ¹¹⁴ The significance of the person’s interest in not revealing one’s sexual preferences may be another example. Meanwhile, the personal interest in having one’s mental privacy respected may be weaker in relation to more trivial information about mental phenomena, of which absolute human rights protection would be less persuasive. One could think of a person’s memory about a specific event, like the lovely sunset one experienced in Italy last summer,Footnote ¹¹⁵ a person’s intention to grab a cup of tea during the coffee break or one’s opinion about a new Netflix series.

Whereas many would probably agree that the secrecy of political opinions deserves stronger privacy protection than the secrecy of a preference for tea or coffee,Footnote ¹¹⁶ much of the area in between is grey. What about emotions: whether one feels happy or sad? What about an opinion about a colleague? A memory about a criminal offence? Or a wild fantasy of becoming famous one day? Is the personal interest in keeping information about these mental states secluded from others significant enough to engage absolute mental privacy protection? It is hard to answer this question in isolation from other relevant considerations – perhaps most notably, the context within which one is obliged to reveal information about them. For instance, in the future, neuropredictive tools may well reveal information about different types of mental phenomena, ranging from emotional responses and reduced self-control to sexual orientation and information indicative of mental disorders. Whereas, in general, the significance of the personal interest in not revealing these types of information plausibly differs between them, their disclosure and use in the context of criminal justice for risk assessment may have similar adverse effects on the interest of personal liberty. For example, all such information could potentially contribute to the assessment of a certain expected risk of recidivism and, therefore, leading to the rejection of a parole request. Let us turn to considering the relevance of the context of a mental privacy interference in more detail in the next section.

4.3.2 Context of the Privacy Interference

The significance of the personal interest in not disclosing mental states – which may be a relevant consideration for granting absolute protection, as discussed in the previous section – plausibly depends on the context within which one is obliged to do so. In some contexts, being forced to revealing one’s true views and ideas may be unpleasant but is unlikely to harm vital personal interests. Meanwhile, in other contexts, the revelation of private ideas, thoughts and feelings may have significant detrimental effects, ranging from not being offered a job, to the deprivation of liberty, and even death.

Consider, for instance, how the risk of being harmed by expressing one’s homosexual feelings and desires depends significantly on the country (legal system) in which they are disclosed. Or consider the obligation to provide information about one’s emotions and intentions in the context of requesting a gun license, which could result in the rejection of one’s request, compared to being obliged to disclose emotions and intentions in the context of a criminal prosecution, which could result in a conviction. Whereas the former seems not to face any principled objections, and many would feel it should be permissible, the latter is in principle prohibited in most legal systems by the right to silence and the privilege against self-incrimination,Footnote ¹¹⁷ which, according to some, primarily aims to protect the accused’s mental privacy.Footnote ¹¹⁸ As such, the context wherein one reveals information about specific mental phenomena appears to affect the personal interest in (not) doing so. Perhaps, this could inform our normative analysis of whether, when and which mental states deserve either absolute or qualified protection from human rights.

These intuitions about different informational norms applying in different (social) contexts are reminiscent of Nissenbaum’s philosophical account on information privacy. In her book Privacy in Context, Nissenbaum argues that privacy concerns should not be limited solely to concerns about control over and access to personal data. Rather, privacy is also about context-dependent social norms that govern the “appropriate flow of information” in different settings and relationships, ranging from family, friends and the workplace to schools, health care and law enforcement. Nissenbaum calls this conception of privacy “contextual integrity”,Footnote ¹¹⁹ which, in practice, means that different rules and norms apply about confidentiality, access to and control over personal data across different contexts, such as the context of friendship, doctor-patient relationships and criminal justice.Footnote ¹²⁰

Although the dominant account in law conceives of privacy as control over personal information, the ECtHR does consider the context of an interference with personal data relevant under Article 8 ECHR. In determining whether an interference with personal data infringes the right to respect for private life, “the Court will have due regard to the specific context in which the information at issue has been recorded and retained”.Footnote ¹²¹ Perhaps, a context-based understanding of privacy may also inform our legal thinking about attributing either absolute or qualified protection to interferences with mental privacy. This may be particularly relevant to the evaluation of mental privacy interference in the context of criminal justice, such as through neuroprediction, since the personal interests at stake in this context are often significant, such as the limitation of personal liberty and a possible decline of well-being as a result of extending the duration of incarceration (due to one’s being at “high risk” of reoffending).

4.3.3 Characteristics of the Victim: Vulnerability

When assessing, under Article 3 ECHR, whether a specific treatment attains a minimum level of severity and thus engages absolute protection of bodily and mental integrity from the prohibition of ill-treatment, the ECtHR takes account of a variety of personal characteristics of the victim, such as their sex, age and state of health. In the case of Khlaifia and Others/Italy, the Grand Chamber phrases and, arguably, broadens this factor by appealing in more general terms to the victim’s vulnerability: “In order to determine whether the threshold of severity has been reached, the Court also takes other factors into consideration, in particular (…) [w]hether the victim is in a vulnerable situation, which is normally the case for persons deprived of their liberty.”Footnote ¹²²

Various groups of people have been identified as being particularly vulnerable in the ECtHR’s case law, including children, people with mental disabilities and persons deprived of their liberty.Footnote ¹²³ These groups are considered vulnerable because they are more susceptible to harm than others.Footnote ¹²⁴ By recognising them as vulnerable, the ECtHR acknowledges their challenges and specific needs and underlines the duty of states to provide enhanced protection of people belonging to these groups.Footnote ¹²⁵

Could a person’s vulnerability also be relevant to the question of whether an interference with mental privacy should engage either absolute or qualified protection from human rights? Some people may be more vulnerable to (severe) interference with their mental privacy than others. Think, for example, of those who are illiterate, using a BCI for non-medical purposes such as in gaming, who might be less able to understand, oversee and, therefore, resist the potential threats to mental privacy posed by emerging neurotechnology. Other vulnerable persons may include minors, elderly, people with mental disabilitiesFootnote ¹²⁶ and convicted persons deprived of their liberty who are ‘offered’ neurotechnology.Footnote ¹²⁷

Much has been written about different types and conceptions of “vulnerability” and how it could be relevant to the law. Here, we wish to briefly point to the work of Robert Goodin, who argues that governments, private companies and natural persons bear a special responsibility for protecting those who are particularly vulnerable.Footnote ¹²⁸ Goodin conceives of vulnerability as a relational concept. People are vulnerable to the actions of others – that is, to the infliction of harm on them by others. This kind of relational vulnerability creates a special responsibility of those to whom others are particularly vulnerable: “If A’s interests are vulnerable to B’s actions and choices, B has a special responsibility to protect A’s interest; the strength of this responsibility depends strictly upon the degree to which B can affect A’s interests.”Footnote ¹²⁹ This special responsibility applies primarily to the protection of so-called “vital interests” or “primary goods”, such as food, shelter, physical and mental health, self-respect and civil liberties (which includes the civil liberty of mental privacy).Footnote ¹³⁰

Goodin argues that a person’s vulnerability or dependency does not really cause moral concern in and of itself. However, it “necessarily creates opportunities for the strong to exploit the weakness of those who are vulnerable and dependent”, and this is what causes moral concern and requires taking special responsibility to protect the vulnerable.Footnote ¹³¹ Exploitation is often defined as taking unfair advantage of other people, which implies a normative judgement about those who exploit.Footnote ¹³² Perhaps, this could be relevant to the law too, as a person’s vulnerable status may not only increase their risk of being harmed (i.e., having their mental privacy interfered with) but also add an additional wrong when others, such as government officials, take unfair advantage of a person’s vulnerable status by yielding, processing and/or disclosing intimate information about people’s private mental states and content.

Possibly, this additional wrong could be relevant to determining whether an interference with mental privacy should engage either absolute or qualified human rights protection.Footnote ¹³³ As Goodin argues, in no case should people’s vulnerabilities “be so severe and asymmetrical that one party has exclusive, discretionary control over resources that the other needs to protect his vital interests”.Footnote ¹³⁴ He calls this the principle of “preventing exploitable vulnerabilities”. If we apply this principle to the case of protecting mental privacy, absolute prohibition of discretionary control by others over revealing mental content of (certain) vulnerable persons may be appropriate.Footnote ¹³⁵ Whether and how this principle of “preventing exploitable vulnerabilities” could indeed be relevant to the application of the absolute right to freedom of thought, and whether it would fit within the ICCPR and ECHR frameworks, merits further elaboration.

Regarding the neuroprediction of convicted persons, different vulnerabilities could, potentially, be relevant. First, the vulnerable position arising from incarceration – that is, the incarcerated person’s “vulnerability at the hands of the authorities, who exercise complete control over her throughout her detention”.Footnote ¹³⁶ Second, research shows that incarcerated persons have high rates of psychiatric disorders,Footnote ¹³⁷ which could add to a person’s vulnerability.Footnote ¹³⁸ Third, one could argue that, with the rise of neurotechnologies, every person is inherently vulnerable to the exploitation of the lack of control we have over the neural correlates of mental states. As Bublitz argues, “many neuroimaging methods exploit the fact that people lack control over the physiological correlates of thought”.Footnote ¹³⁹ Whether, and, if so, to what extent, these different forms of vulnerability should indeed be relevant to the application of the absolute right to freedom of thought is an open question in need of further research.

4.3.4 Brief Recap

In this section, we explored how the law could distinguish between the qualified protection of mental privacy, provided by the right to privacy and right to freedom of expression, and the absolute protection offered by the right to freedom of thought. This will be highly relevant for the permissibility of mental privacy interferences, which are likely to occur in neurorehabilitation. Analogous to the “minimal level of severity” threshold for the applicability of Article 3 ECHR, we explored the possibility of developing a severity threshold for infringing the privacy dimension of the absolute right to freedom of thought. For the construction of such a threshold, we suggested four potentially relevant factors: (1) the method of revealing mental phenomena, focusing on the level of the subject’s control; (2) the significance of the personal interest in not revealing specific mental phenomena; (3) the context of the privacy interference; and (4) the person’s vulnerability.