A "Sudden Appearance" model for the Evolution of Human Cognition and Language

Abstract

The debate over the evolution of an innate language capacity seems to divide into two principle schools of thought. Jackendoff (1999a, 1999b) has argued that language processing is based on three autonomous generative components, phonological, syntactic, and semantic/conceptual and he is committed to the view that the language faculty evolved incrementally through natural selection. Pinker (1994, 333) also sees ``no reason to doubt that the principle explanation is the same as for any other complex instinct or organ, Darwin's theory of natural selection", when theorizing about language evolution. An alternative approach has been taken recently by Hauser, Chomsky and Fitch (2002). They argue that the property that makes human language unique (recursion), may be a recent emergence in hominid evolution. It follows from this line of thought that most of the anatomical characteristics that support language (e.g. vocal tract and controlled breathing) may be merely variations of previously evolved biological structures, and not of a different kind. Leaving aside the argument of whether these structures evolved gradually, they did not evolve nor were they ``tuned" to serve the faculty of language. Jackendoff (1999a) accuses those who do not accept that language arose gradually through natural selection as having been ``forced to devalue evolutionary argumentation". Jackendoff's concern seems to stem from the view that there is only one way that evolution can proceed, through gradual change honed by natural selection. My concern is for the neglect of the vast amount of evidence supporting the theory that modern humans did not emerged in a gradual, step-wise fashion. Here I argue that hominins evolved through major evolutionary leaps, which may have numbered only two or three significant mutation ``events". Neoteny (the retention of infant or juvenile growth rates) has been the major force in the evolution of our primate ancestors and this process can explain the sudden emergence of many of the traits that define what it means to be human, including the sudden emergence of human cognition and language.