Introduction

Both rationalist and empiricist perspectives on language acquisition make predictions regarding the nature of biological foundations for language knowledge. As we saw in chapter 4, Chomsky hypothesizes that the brain predetermines how language knowledge is acquired, and represents this knowledge as distinct from other cognitive knowledge, i.e., as modular. In contrast, for empiricist perspectives, “distributed” representations of language knowledge in the brain are hypothesized to resemble “the organization of neural nets” (Bates and MacWhinney 1989, 33). Both predictions provoke us to look carefully at brain structure and function, although neither paradigm yet precisely predicts how brain development underlies language development.

Such predictions may soon be addressed more precisely through recent technical advances in brain imaging methodologies. (See ERP, fMRI, MEG and electrical stimulation mapping in Glossary.) These new instruments will add evidence to decades of research on language pathologies caused by various forms of brain injury and allow us for the first time to study the normal brain engaged in normal language functions. Some can be extended to the study of normal children (e.g., Posner et al. 2001; Molfese et al. 2001; Casey 2002).

Lenneberg 1967 laid foundations for scientific study of this area. His behavioral observations of “Developmental Milestones in Motor and Language Development” (appendix 1) implied a biological and maturational component in language development, similar to motoric development.