Experiential factors such as long-term deliberate practice are powerful and necessary conditions for outstanding achievement. Nevertheless, to be able to reject the role of biology based individual differences (including genetic ones) in the manifestation of talent requires designs that expose heterogeneous samples to so-called testing-the-limits conditions, allowing asymptotic levels of performance to be analyzed comparatively. When such research has been conducted, as in the field of lifespan cognition, individual differences, including biology based ones, come to the fore and demonstrate that the orchestration of excellence requires joint attention to genetic–biological and experiential factors.

I will argue that we cannot understand imitation unless we know more about its function. By comparing the two examples presented by Byrne & Russon I show how the imitative behaviour of orangutans can be interpreted as a homologue of human imitation during play. In contrast, the lack of data leave the role of imitation in gorillas doubtful.

An alternative account of the locus equation phenomenon based on recent theories of speech movement planning is provided. It is similar to Sussman et al.'s account in positing that our productions are tuned to satisfy auditory constraints. It differs by suggesting that the locus equation effect may be an epiphenomenon of a planning process that satisfies simpler auditory constraints.

I support the application of the “evolution as tinkering” idea to vocalization and emphasize that some of the subcortical parts of the brain circuits used for speech organs retain features common to nonprimate mammals, and in some cases to lower vertebrates, pointing up the importance of cortical evolution as suggested by MacNeilage.

In a simple economic decision problem with multi-tasking the dimensionality of the problem is neither a necessary nor a sufficient measure of complexity. Rather, dimension is good measure of complexity when there is an aggregate resource constraint that creates an interaction between the different activities, resulting in a problem with high algorithmic complexity.

Millikan's externalist account of concept acquisition cannot completely avoid the distinction between central (defining) and peripheral (characteristic) features, because some knowledge is required to achieve reference and to decide what kind of information to record about the identified substances. However, the emphasis on external reference may provide the requisite principled way to make this distinction.

Apes imitate the effects of others' actions, but the evidence for program-level imitation seems contradictory and the evidence against bodily imitation and trial and error in learning the organization of complex activities seems ambiguous. Action-level imitations are more flexible than described and may derive from imitation of the effects of others' actions on objects.

Howe et al. suggest that most talents can be explained in terms of practice and other environmental effects, and only exceptionally by innate factors. This commentary provides an illustration of one such exception: performance on the Embedded Figures Test by people with autism and their relatives.

Sussman et al. state that auditory systems exploit linear correlations in the sound signal in order to identify perceptual categories. Can the auditory system recognize linearity? In bats and owls, separability of emergent features is an additional constraint that goes beyond linearity and for which linearity is not a necessary prerequisite.

Halford et al. are not redefining capacity in the sense of limit on resources but in the sense of limits on what resources can do. Furthermore, the necessity of using resource theory as a theoretical frame is questionable.

In presenting her attractive theory of concepts, Millikan makes an unwarranted assumption about the role of language in concept acquisition. The phoneme string, rather than the “word” as a semantic entity, may suffice to play the crucial role in the acquisition of substance concepts. Hence Millikan may underestimate the degree of similarity between language and other media of perception.

This commentary supports MacNeilage's dismissal of an evolutionary development from sign language to spoken language but presents evidence of a feature in sign language (echo phonology) that links iconic signs to abstract vocal syllables. These data provide an insight into possible mechanism by which iconic manual gestures accompanied by vocalisation could have provided a route for the evolution of spoken language with its characteristically arbitrary form–meaning relationship.

User intentions invoked to account for the distinctive way in which public-language natural-kind terms gather their extensions are inapplicable in the case of Millikan's substance concepts. I suggest that theoretical justification is preferable and available and raise exploratory questions about the applicability of the notion of substance concepts to the genesis of self concepts.

Measurements of the dimensionality of chaotic attractors obtained on behavioral data represent the task complexity and also could be hypothesized to reflect the number of synchronized neural groups involved in the generation of the data. The changes in dimensionality for different experimental conditions suggest that limited processing capacity, task complexity, demand, and synchrony in neural firing might be closely related.

Locus equations fail to provide adequate abstraction to capture the English phoneme /g/. They also cannot characterize final consonants or their relation to pre-vocalic consonants. However, locus equations are approximately abstract enough to define the upper limit on phonological distinctions for place of articulation. Hence, locus equations seem to mediate phonetic and phonological perceptual abilities.

There was little disagreement among commentators about whether speech production involves a frame/content mode of organization, but there was some disagreement with the contention that frames evolved from ingestive cyclicities and were mediated via a medial “intrinsic” system.

Byrne & Russon suggest that there are two kinds of imitation learning – action level and program level – and that the latter is critical for great apes' learning. I have interpreted this phenomenon from the standpoint of clinical neuropsychology and conjecture that action-level imitation might be related to parietal lobe function and program-level imitation might be related to frontal lobe function.

We present a theoretical model and corresponding research design (Bronfenbrenner & Ceci 1994) that could yield stronger evidence for (or perhaps against) Howe et al.'s conclusions. The model assesses levels of heritability (h²) under different amounts of training and practice, thus providing estimates of the independent contribution of “innate talent” to the quality of development outcomes. The design can also reveal the extent to which this independent contribution varies systematically as a function of other influential factors identified by Howe et al.

Two assertions of Halford et al. are critiqued: their claim of priority in relational complexity analysis and the sufficiency for cognitive development of their relational-complexity analysis of tasks. Critical discussion of concrete task analyses (i.e., the relational complexity of proportionality problems, of balance scale problems, and the Tower of Hanoi) serves, by way of counterexamples, to highlight problems in their method.

Millikan's proposal of a common structure of substance concepts does not explain certain conspicuous findings in the psychological literature such as typicality effects, the context sensitivity of these effects, and slips of the tongue. Moreover, it is unclear how antidescriptionism could be relevant to psychological theorizing. Finally, it does not seem to be true that concepts of individuals, stuff, and real kinds have a common structure in older children and in adults.