BRAIN EVOLUTION AND NEUROLINGUISTIC PRECONDITIONS

This target article presents a plausible evolutionary scenario for the emergence of the neural preconditions for language in the hominid lin eage. In pleistocene primate lineages there was a paired evolutionary expansion of frontal and parietal neocortex (through certain well-docu mented adaptive changes associated with manipulative behaviors) result ing, in ancestral hominids, in an incipient Broca's region and in a co nfigurationally unique junction of the parietal, occipital, and tempor al lobes of the brain (the POT). On our view, the development of the P OT in our ancestors resulted in the neuroanatomical substrate consiste nt with the ability for representations in modality-neutral associatio n cortex and, as a result of structure-imposing interaction with Broca 's area, the hierarchically structured ''conceptual structure.'' Evide nce from paleoneurology and comparative primate neuroanatomy is used t o argue that Homo habilis (2.5-2 million years ago) was the first homi nid to have the appropriate gross neuroanatomical configuration to sup port conceptual structure. We thus suggest that the neural preconditio ns for language are met in H. habilis. Finally, we advocate a theory o f language acquisition that uses conceptual structures as input to the learning procedures, thus bridging the gap between it and language.