Physical competence is acquired through animals' embodied interaction with their physical environments, and psychological competence is acquired through situated interaction with other agents. The acquired neural models essential to these competencies are implicit and permit more fluent and nuanced behavior than explicit models. The challenge is to understand how such models are acquired and used to control behavior.

This commentary compares clinical aspects of ketamine with the amphetamine model of schizophrenia. Hallucinations and loss of insight, associated with amphetamine, seem more schizophrenia-like. Flat affect encountered with ketamine is closer to the clinical presentation in schizophrenia. We argue that flat affect is not a sign of schizophrenia, but rather, a risk factor for chronic schizophrenia.

Aggleton & Brown suggest that whereas familiarity is computed in perirhinal cortex, the hippocampus contributes to recollection. This account raises issues about the definition of amnesia, clarifies confusion about dual-process models of recognition, and sits comfortably with accounts of hippocampal function from outside the amnesia literature. The model can – and should – be tested. Some preliminary data suggest that it may need changes.

We argue that ownership is a highly flexible concept, shaped by both innate and learned aspects, and heavily influenced by culture. Boyer's model focuses solely on universal personal ownership, neglecting other forms such as shared ownership, fractionalized property rights, and the ownership of the meanings and memories attached to possessions. A comprehensive understanding requires considering diverse human relationships with objects.

Labor market and real-life studies were not designed to discriminate between evolutionary and taste-based and stereotype explanations for the beauty premium, have too many confounding effects, and lack crucial information. Smaller-stake and experimental studies provide more compelling evidence in favor of mating motives and suggest the direction of future research for the economists' field studies.

This commentary offers two criticisms of Block's account of phenomenal consciousness and a brief sketch of a rival account. The negative points are that monitoring consciousness also involves the possession of certain states and that phenomenal consciousness inevitably involves some sort of monitoring. My positive suggestion is that “phenomenal consciousness” may refer to our ability to monitor the rich but preconceptual states that retain perceptual information for complex processing.

The argument by Burkart et al. in the target article relates to fluid (not general) intelligence: a domain-general ability involved in complex, novel problem solving, and strongly related to working memory and executive functions. A formative framework, under which the general factor of intelligence is the common consequence, not the common cause of the covariance among tests is more in line with an evolutionary approach.

This commentary addresses the strength of the comparative approach to the study of sex differences in pain. Animal studies can focus our attention on mechanisms of sex differences in these clinical sex differences. Important sex differences are seen in descending pain modulation, thereby providing an explanation for the observation of sex differences in pain perception. [berkley]