Müller provides a valuable synthesis of neurobiological evidence on the epigenetic development of neural structures involved in language acquisition. The pluripotentiality of developing neural tissue crucially constrains linguistic/cognitive theorizing about supposedly innate neural mechanisms and contributes significantly to our understanding of experience–dependent processes involved in language acquisition. Without this understanding, any proposed explanation of language acquisition is suspect.

Müller argues that double dissociations do not imply underlying modularity of the cognitive system, citing neural networks as examples of fully distributed systems that can give rise to double dissociations. We challenge this claim, noting that suchdouble dissociations typically do not “scale-up,” and that even some singledissociations can be difficult to account for in a distributed system.

I enlarge on the theme that the brain mechanisms required for languageand other aspects of the human mind evolved through selective changes in the regulatory genes governing growth. Extension of the period of postnatal growth increases the role of the environment in structuring the brain, and spatiotemporal programming (heterochrony) ofgrowth might explain hierarchical representation, hemispheric specialization, and perhaps sex differences.

The study of signed languages has inspired scientific' speculation regarding foundations of human language. Relationships between the acquisition of sign language in apes and man are discounted on logical grounds. Evidence from the differential hreakdown of sign language and manual pantomime places limits on the degree of overlap between language and nonlanguage motor systems. Evidence from functional magnetic resonance imaging reveals neural areas of convergence and divergence underlying signed and spoken languages.

Müller argues that general cognitive skills and linguistic skills are not necessarily independent. However, cross-linguistic evidence from an inherited specific language disorder affecting productive rules suggests significant degrees of modularity, innateness, and universality of language. Confident claims about the overall nature of such a complex system still await more interdisciplinary research.

Müller attempts to downplay cases of dissociation between language and cognition as evidence against the modularity of language. We review cases of associations between verbal and nonverbal abilities as further evidence against the notion of language as an autonomous subsystem. We also point out a discrepancy between his proposal of homologies between nonhuman primates' communication and human language and recent proposals on the evolution of language.

The neuroscientific investigation of sex differences has an unsavoury past, in which scientific claims reinforced and legitimated gender roles in ways that were not scientifically justified. Feminist critics have recently argued that the current use of functional neuroimaging technology in sex differences research largely follows that tradition. These charges of ‘neurosexism’ have been countered with arguments that the research being done is informative and valuable and that an over-emphasis on the perils, rather than the promise, of such research threatens to (...) hinder scientific progress. To investigate the validity of these contrasting concerns, recent functional magnetic resonance imaging (fMRI) investigations of sex differences and citation practices were systematically examined. In line with the notion of neurosexism, the research was found to support the influence of false-positive claims of sex differences in the brain, to enable the proliferation of untested, stereotype-consistent functional interpretations, and to pay insufficient attention to the potential plasticity of sex differences in both brain and mind. This, it is argued, creates a literature biased toward the presentation of sex differences in the brain as extensive, functionally significant, and fixed—and therefore implicitly supportive of a gender essentialist perspective. It is suggested that taking feminist criticisms into account would bring about substantial improvement in the quality of the science, as well as a reduction in socially harmful consequences. (shrink)

In 1873, within two years of the publication of The Descent of Man, Friedrich Max Mueller wrote: There is one difficulty which Mr Darwin has not sufficiently appreciated … There is between the whole animal kingdom on the one side, and man, even in his lowest state, on the other, a barrier which no animal has ever crossed, and that barrier is – Language … If anything has a right to the name of specific difference, it is language, as we (...) find it in man, and in man only … If we removed the name of specific difference from our philosophic dictionaries, I should still hold that nothing deserves the name of man except what is able to speak … a speaking elephant or an elephantine speaker could never be called an elephant.' and ‘If a pig were ever to say to me, “I am a pig” it would ipso facto cease to be a pig’. (shrink)

One can disagree with Müller that it is neurobiologically questionable to suppose that human language is innate, specialized, and species-specific, yet agree that the precise brain mechanisms controlling language in any individual will be influenced by epigenesis and genetic variability, and that the interplay between inherited and acquired aspects of linguistic capacity deserves to be investigated.

Müller's review of the neuroscientific evidence undermines nativist claims for autonomous syntax and the argument from the poverty of the stimulus. Generativists will appeal to data from language acquisition, but here too there is growing evidence against the nativist position. Epigenetic naturalism, the developmental alternative to nativism, can be extended to epigenetic socionaturalism, acknowledging the importance of sociocultural processes in language and cognitive development.