studies with humans have failed to produce evidence that any direct causal relation exists between the asymmetry of one function in an individual and the asymmetry of a different function in that individual. without such evidence, factors external to an individual's nervous system, such as social interactions, may play crucial roles in explaining the directions of all asymmetries at all levels.

population-level asymmetry may be maintained, not by an “evolutionarily stable strategy” pitting a dominant bias against its nondominant opposite, but rather by a genetically based system pitting a directional bias against the absence of any such bias. stability is then achieved through a heterozygotic advantage, maintaining balanced polymorphism. this model may better capture the fundamental trade-off between lateralization and bilateral symmetry.

lateralisation is traditionally viewed by neuroscientists and comparative psychologists from the perspective of the individual; however, for many animals lateralisation evolved in the context of group living. here i discuss the implications of individual lateralisation within the context of the group from an evolutionary ecology perspective, with particular reference to coordinated anti-predator behaviour.

the act/omission distinction is likely to lead to biases and be used as a moral heuristic. however, it is frequently difficult to determine whether this act/omission distinction is responsible for a judgment outside the lab. further, more encompassing theories of omission bias are needed to make progress in dealing with its harmful consequences. one such theory is briefly presented.

sunstein's review of research on moral heuristics is rich and informative – even without his central claim that individuals often commit moral errors. we question the value of positing such a normative moral framework for the study of moral judgment. we also propose an alternative standard for evaluating moral judgments – that of subjective rationality.

the theory put forward by vallortigara & rogers (v&r) to explain the versatility of directional asymmetries at the population level argues that the strength of lateralization is controlled by social learning. this shaping of behavioral asymmetries by a non-stationary pressure probably involves a marked degree of neuroplasticity. i discuss the limits of neuroplasticity along with the evolution of the corpus callosum.

by focusing on mistaken judgments, sunstein provides a theory of performance errors without a theory of moral competence. additionally, sunstein's objections to thought experiments like the footbridge and trolley problems are unsound. exotic and unfamiliar stimuli are used in theory construction throughout the cognitive sciences, and these problems enable us to uncover the implicit structure of our moral intuitions.

vallortigara & rogers (v&r) assume that the alignment of escape responses in gregarious species is the central evolutionary organizer of a wide range of cerebral asymmetries. although it is indeed likely that the benefits of a population asymmetry in social species outweigh its costs, it is hard to see (a) why the population should not oscillate between two subgroups with mirror-image asymmetries, (b) why solitary animals should keep their inherited population asymmetry despite a resulting fitness reduction, and (c) and why so many vertebrate species have comparable cerebral asymmetries.

recent evidence in natural and semi-natural settings has revealed a variety of left-right perceptual asymmetries among vertebrates. these include preferential use of the left or right visual hemifield during activities such as searching for food, agonistic responses, or escape from predators in animals as different as fish, amphibians, reptiles, birds, and mammals. there are obvious disadvantages in showing such directional asymmetries because relevant stimuli may be located to the animal's left or right at random; there is no a priori association between the meaning of a stimulus (e.g., its being a predator or a food item) and its being located to the animal's left or right. moreover, other organisms (e.g., predators) could exploit the predictability of behavior that arises from population-level lateral biases. it might be argued that lateralization of function enhances cognitive capacity and efficiency of the brain, thus counteracting the ecological disadvantages of lateral biases in behavior. however, such an increase in brain efficiency could be obtained by each individual being lateralized without any need to align the direction of the asymmetry in the majority of the individuals of the population. here we argue that the alignment of the direction of behavioral asymmetries at the population level arises as an “evolutionarily stable strategy” under “social” pressures occurring when individually asymmetrical organisms must coordinate their behavior with the behavior of other asymmetrical organisms of the same or different species.

the relative contributions of biological and cultural factors in determining category characteristics almost certainly vary for different categories, so that the results of these simulations on color categories don't necessarily generalize. it is suggested here that categories that pick out structure in the environment of strong behavioral significance to individual agents will be predominantly biologically determined and will converge without interagent communication, whereas those categories that serve primarily to coordinate behavior in a population will require communication to converge.

steels & belpaeme (s&b) take technical and conceptual shortcuts that have significant negative consequences on simulation implementation and agent behavior. justifiably, their model represents a proof of concept of the role of culturalism in category formation; nevertheless, the absence of detailed information concerning the embodiment of agents and the superficial implementation of learning approaches make their results less relevant than they could be.

culture is surely important in human learning. but the relation between culture and psychological mechanism needs clarification in three areas: (1) all learning takes place in real time and through real-time mechanisms; (2) social correlations are just a kind of learnable correlations; and (3) the proper frame of reference for cognitive theories is the perspective of the learner.

the dynamical category uses the sensory-motor coordination to do categorization. if categories are inevitably grounded in sensory-motor coordination, sharing categories may also share the same sensory-motor coordination. concerning this aspect, we discuss the color category as a dynamical categorization. additional to the converging effect of a category by communication, we discuss the diverging effect of communication that creates new categories.

we have found that the left side of faces displayed in rembrandt's portraits capture how humans rank male dominance, helping to coordinate avoidance behaviors among asymmetric individuals. moreover, the left side of faces may also coordinate approach responses, like attractiveness, in human females. therefore, adding sexual selection to dominance paints a more realistic picture of what the contralateral right hemisphere is doing.

vallortigara & rogers's (v&r's) proposal that directional asymmetries evolved under social pressures raises questions about the ontogenetic mechanisms subserving the alignment of asymmetries in a population. neuro-ontogenetic principles suggest that epigenetic factors are decisively involved in the determination of individual lateralization and that genetic factors align their direction. clearly, directional asymmetry has an epigenetic trait.

steels & belpaeme (s&b) refer to the neural plausibility and evolutionary plausibility of their algorithms. although this is not central to their goal of effective artificial agents, their algorithms are not neurally or evolutionarily plausible. their communication games are interesting, and more complex games would lead to more effective agents. however, the algorithms could be improved either by using standard subsymbolic algorithms or by algorithms that are really neurally or evolutionarily plausible.

the implications that steels & belpaeme's (s&b's) models have for memetics are discussed. the results demonstrate the power of memes (in this case colour words) to influence both concept formation, and the creation of innate concepts. they provide further evidence for the memetic drive hypothesis, with implications for the evolution of the human brain and for group differences in categorisation.

a mental heuristic is a shortcut (means) to a desired end. in the moral (as opposed to factual) realm, the means/end distinction is not self-evident: how do we decide whether a given moral intuition is a mere heuristic to achieve some freestanding moral principle, or instead a freestanding moral principle in its own right? i discuss sunstein's solution to that threshold difficulty in translating “heuristics” to the moral realm.

direction of the embyro's head rotation is determined by asymmetrical expression of several genes (such as shh, nodal, lefty, and fgf8) in hensen's node. this genetically determined head-turning bias provides a base for light-aligned population lateralization in chicks, in which the direction of the lateralization is determined by genetic factors and the degree of the lateralization is determined by environmental factors.

moral heuristics are pervasive, and they produce moral errors. we can identify those errors as such even if we do not endorse any contentious moral view. to accept this point, it is also unnecessary to make controversial claims about moral truth. but the notion of moral heuristics can be understood in diverse ways, and a great deal of work remains to be done in understanding the nature of moral intuitions, especially those that operate automatically and nonreflectively, and in exploring the possibility of altering such intuitions through modest changes in context and narrative.