Thinking outside the cortex: social motivation in the evolution and development of language.

Alteration of the organization of social and motivational neuroanatomical circuitry must have been an essential step in the evolution of human language. Development of vocal communication across species, particularly birdsong, and new research on the neural organization and evolution of social and motivational circuitry, together suggest that human language is the result of an obligatory link of a powerful cortico-striatal learning system, and subcortical socio-motivational circuitry.