Developmental aspects of the frame/content perspective are explored in relation to (1) transitions in early language acquisition, (2) possible differential neurological control for babbling and early and later speech, and (3) development of word production templates in precocious early speakers. Proportionally high frequency of bilabial stops in early stable words versus babble offers advantages for afferent monitoring and supporting “frame dominance.”

A narrow focus on the jaw (or on motor generators) does not account for individual and language-specific differences in babbling and early speech. Furthermore, data from Yoshinaga-Itano's laboratory support earlier findings that show glottal rather than oral stops in deaf infants' babbling: audition is crucial for developing normal syllables.

Because the evolution of speech production is beyond our expertise (and perhaps beyond everyone's expertise) we restrict our comments to areas in which data actually exist. We provide articulatory evidence consistent with the claims made about syllable structure in adult speech and infant babbling, but we also voice some disagreement about speech errors and the typing data.

There is not enough reason to believe that syllables are primary in speech and evolved from the cyclic movements of chewing. There are many differences between chewing and speech and it is equally plausible that what is primary in speech is a succession of auditorily robust modulations of various acoustic parameters (amplitude, periodicity, spectrum, pitch); syllables could have evolved from this.

The target article raises the question of whether transcription-based evidence is sufficient to support assumptions relating to patterns of mandibular activity in young children. Studies on the perception of both adult and infant speech indicate that the argument needs to be reexamined on the basis of acoustic and articulatory data.

Much of the material MacNeilage cites to support his frame/content theory for the evolution of speech production in humans is not unique to mammals. Parallels can be drawn for comparable evolution of vocal flexibility (specifically the reproduction of human speech) in birds. I describe several such parallels and conclude that MacNeilage's hypotheses may have broader application than he envisioned.

The evolutionary continuity between the prespeech functions of premotor cortex and its new linguistic functions, the main thesis of MacNeilage's target article, is confirmed by the recent discovery of “mirror” neurons in monkeys and a corresponding action-observation/action-execution matching system in humans. Physiological data (and other considerations) appear to indicate, however, that brachiomanual gestures played a greater role in language evolution than MacNeilage would like to admit.

Parrots prepare for vocalization by a ventro-caudal retraction of the larynx. This laryngeal movement, which “frames” vocal sequences, is similar to a movement used by pigeons as a preparation for suction drinking. The air-pressure events involved in such movements can trigger either suction drinking or vocalization. This suggests a possible evolutionary link between these ingestive and vocal mechanisms.

This commentary deals with the relation between human language and nonverbal signals used by nonhuman primates. It suggests that human language could have developed through the interaction of procedural learning with a preexisting system for socio-affective communication. The introduction of “content” into existing “frames” requires a neurobiologically plausible learning mechanism.

This commentary focusses on MacNeilage's arguments and evidence that the development of cerebral cortical controls over cyclic ingestive movements has provided substrates for the evolution of speech production. It outlines evidence from experimental approaches using cortical stimulation, inactivation, and single neuron recording in primates that lateral frontal cortical regions are indeed crucial for the generation and guidance of cyclic orofacial movements.

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.

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.

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.

This essay in the “anthropology of science” is about how cognition constrains culture in producing science. The example is folk biology, whose cultural recurrence issues from the very same domain-specific cognitive universals that provide the historical backbone of systematic biology. Humans everywhere think about plants and animals in highly structured ways. People have similar folk-biological taxonomies composed of essence-based, species-like groups and the ranking of species into lower- and higher-order groups. Such taxonomies are not as arbitrary in structure and content, nor as variable across cultures, as the assembly of entities into cosmologies, materials, or social groups. These structures are routine products of our “habits of mind,” which may in part be naturally selected to grasp relevant and recurrent “habits of the world.” An experiment illustrates that the same taxonomic rank is preferred for making biological inferences in two diverse populations: Lowland Maya and Midwest Americans. These findings cannot be explained by domain-general models of similarity because such models cannot account for why both cultures prefer species-like groups, although Americans have relatively little actual knowledge or experience at this level. This supports a modular view of folk biology as a core domain of human knowledge and as a special player, or “core meme,” in the selection processes by which cultures evolve. Structural aspects of folk taxonomy provide people in different cultures with the built-in constraints and flexibility that allow them to understand and respond appropriately to different cultural and ecological settings. Another set of reasoning experiments shows that Maya, American folk, and scientists use similarly structured taxonomies in somewhat different ways to extend their understanding of the world in the face of uncertainty. Although folk and scientific taxonomies diverge historically, they continue to interact. The theory of evolution may ultimately dispense with the core concepts of folk biology, including species, taxonomy, and teleology; in practice, however, these may remain indispensable to doing scientific work. Moreover, theory-driven scientific knowledge cannot simply replace folk knowledge in everyday life. Folk-biological knowledge is not driven by implicit or inchoate theories of the sort science aims to make more accurate and perfect.

Differences in mutation rates, transmission chain-length, phenotypic manifestations, or the relative complexity of the mental representations in which they are embedded do not distinguish between “core” (intramodular) and “developing” (intermodular) memes, as Atran suggests. Dividing memes into types seems premature when our knowledge of mental representation is as imprecise as the unit of biological inheritance was in Darwin's time.

Atran's account of cultural transmission can be further refined by considering constraints from early-developed, domain-specific intuitive ontological understanding. These suggest specific predictions about the cultural survival of “memes,” depending on the way they activate intuitive understanding. There is no general dynamic of cultural inheritance; only complex predictions for domain-specific competencies that cut across cultural domains.

A concern for cultural specificity, the staple of traditional anthropological research, survives the transition to domain-specific accounts of cognitive structuring such as Atran's, and is arguably better off for having made the transition. The identification of domain-specific processes provide us with criteria for sorting cultural differences and integrating cultural concerns within cognitive science.

The evidence for a panhuman, cognitively rooted, essence-based concept of basic natural kind and for certain prototypical phenomenal forms is increasingly compelling, but there remain doubts as to whether these two elements combine with a principle of taxonomy to form a unified, domain-specific theory in the way Atran claims. The appropriateness of the notion of meme can also be questioned, as can the assertion that humans are always grouped in ethnobiological classifications in unambiguous contrast to other animals.

Atran's thesis has strong implications for the doctrine of externalism in concepts (Fodor 1994). Beliefs about biological kinds may involve a degree of deference to scientific categories, but these categories are not truly scientific. They involve instead a folk view of science itself.

Atran's treatment of classification suggests a need to recognize the difference between ontological categories and less metaphysically fundamental distinctions. The shift that scientists have made from classes to individuals may not be as pervasive as he proposes, and the same may be said for the abandonment of essences. It is also possible that the sort of causality that is of concern to scientists plays a role in folk classification.