Impoverished resources may direct the pathologic central nervous system toward local solutions during ontogeny. The resultant motor behavior can be systemically optimal without being functionally optimal. Therapeutic intervention should focus on facilitating function (rather than “normalcy”) by encouraging behavioral exploration through appropriate combinations of task and environmental variations with respect to individual capabilities. Some health professions have already adopted this philosophy.

Using movement disorders to understand the central nervous system's goals for motor behaviour may be easier in neurological models with a focal lesion of sudden onset, because the distinction between primary and adaptive changes may be clearer than in slowly progressive and/or diffuse neurological disease.

Researchers and clinicians have different goals and constraints in trying to understand and treat movement disorders. Research on primary and secondary aspects of disorders may lead to effective treatment aimed at restoring functional movements even if the primary disorder cannot be cured. Similarly, movement patterns may be maladaptive and hence need therapeutic intervention to restore functional movement skills.

We start with a number of philosophical and theoretical issues related to motor control, proceed through a spectrum of problems related to the role of adaptive changes in the central nervous system (CNS) in response to a primary disorder, and end with tentative practical recommendations. We consider the hierarchical and dynamic approaches to motor control not as incompatible alternatives but as ways of approaching two equally important issues, those of control and coordination. Professionals working in the area of physical therapy and rehabilitation should make use of the adaptive abilities of the CNS, identify goals, provide tools, and allow the CNS to develop optimal strategies. Therapists should intervene if they suspect that the CNS settles down in a local rather than a global optimum because of such factors as pain or the lack of a long-term predictive ability. Adaptive changes within the CNS may be important not only in pathologies but also in cases of specialized training, normal growth, and normal ageing.

Organisms engage in various activities that are directed at objects, whether real or imagined. Such activities may be termed “intentional relations.” We present a four-level framework of social understanding that organizes the ways in which social organisms represent the intentional relations of themselves and other agents. We presuppose that the information available to an organism about its own intentional relations (or first person information) is qualitatively different from the information available to that organism about other agents’ intentional relations (or third person information). However, through the integration of these two sources of information, it is possible to generate representations of intentional relations that are uniformly applicable to the activities of both self and other. The four levels of the framework differ in the extent to which such integration occurs and in the degree to which imagination is involved in generating these representations. Most animals exist at the lowest level, at which integration of first and third person sources of information does not occur. Of nonhuman species, only great apes exhibit social understanding at intermediate levels, at which integration of these sources of information provides uniform representations of intentional relations. Only humans attain the highest level, at which it is possible to represent intentional relations with mental objects. We propose that with the development of the imagination, children progress through three stages, equivalent to the later three levels of the framework. The abnormalities in social understanding of autistic individuals are hypothesized to result from a failure to develop integrated representations of intentional relations.

Barresi & Moore (B&M) provide a useful tool for the comparative study of social cognition that could, however, be improved by more subtle analysis of first person information about intentional relations. Knowledge of misrepresentation also needs to be better handled within the theory. I urge skepticism about B&M's sweeping phylogenetic claims.

Barresi & Moore contrast two theories of autism: (1) in autism there is a general inability to integrate first and third person information (of any kind), and (2) in autism there is a specific inability to represent an agent's perceptual or volitional mental state being about another agents mental state. Two lines of experimental evidence suggest that the first of these is too broad, favoring instead the more specific “theory of mind” account.

The psychology of emotions illuminates the questions of intentional capacities raised by Barresi & Moore (B&M). Complex emotions require the development of a sense of self and are based on social comparisons between mainly imagined objects. The fourth level in B&M's framework requires something like a constructive agent rather than a mental agent.

In our commentary we elaborate on Barresi & Moore's use of language as a tool. In particular, we highlight the importance of cognitive linguistic research with its emphasis on the relation between morpnosyntax and intentional schemes. We also speculate about how language itself might play a role in children's integration of first and third person knowledge.

The difference between first and third person information may be thought of as a difference in either informational content or informational modality. Each option faces some problems. I try to sort out some of these issues and raise a question about the explanatory force of the notion of a schema.

Barresi & Moore fail to provide a satisfactory account for the development of social understanding because of (1) their ambiguous characterization of the relationship between the intentional schema and shared intentional activities, (2) their underestimation of the representational capacities of infants, and (3) their overreliance on the simulationist assumption that understanding others is tantamount to sharing their experience.

Barresi & Moore's account has at least two implications for moral psychology. First, it appears to provide support for cognitive theories of moral competence. Second, their claim that the development of social understanding depends upon domain-general changes in cognitive ability appears to oppose the idea that moral competence is under-pinned by a moral module.

The data reviewed in Barresi & Moore's treatment of social understanding is recast in terms of a model of social intelligence that was advanced some time ago (Gallup 1982). When it comes to their analysis of the behavior of other individuals, most primates (and humans younger than 18 months of age) appear to function as radical behaviorists, whereas chimpanzees and older infants show evidence of becoming primitive cognitive psychologists.

Second person intentional relations, involving intentional activities directed at the perceptor, are qualitatively different from first and third person relations. They generate a peculiar, bidirectional kind of intentionality, especially in the realm of visual perception. Systems specialized in dealing with this have been selected by evolution. These systems can be considered to be the evolutionary precursors to the human theory of mind.

Although their thesis is generally sound, Barresi & Moore give insufficient attention to the need for a methodology, whether simulation based or theory-based, for choosing among alternative possible matches of first person and third person information. This choice must be sensitive to contextual information, including past behavior. Moreover, apart from simulation or theory, first person information would not help predict future behavior.

Immediate imitation is likely to be a major, direct input to Barresi & Moore's level 2 competence, but deferred imitation is unlikely to play a key role in the transition to level 3, because (1) the attribution of first person knowledge is neither a necessary cause nor an obvious consequence of deferred imitation, and (2) deferred imitation does not correlate phylogenetically with capacities that more plausibly either yield or reflect a concept of intentional agency.

Barresi & Moore provide a welcome focus on children's abilities to integrate first and third person information about intentional relations but they pay insufficient attention to the origins of children's understanding of the nature of subjective orientations vis-à-vis a shared world and the potential significance of such understanding as a source (rather than an outcome) of domain-general information-processing capacities.

The “intentional schema” seems identical to or dependent upon kinesthetic–visual matching, both of which account for similar empirical findings. The intentional schema, however, fails to account for variability in children's understanding of false belief and differences in children's understanding of self and other in pretense.

The intentional schema may not be sufficiently characterized to make questions about its role in individual and species development intelligible. The idea of metarepresentation may perhaps give it enough content. The importance of metarepresentation itself, however, can be called into question.

The intentionality schema is an abstraction that relates phylogenetic and ontogenetic sequences of social understanding, but it also obscures the differences between humans and other primates. In particular, it ignores human social developmental and communicative history and the important roles that language plays in human understanding of others' intentional states.