Many people have argued that the evolution of the human language faculty cannot be explained by Darwinian natural selection. Chomsky and Gould have suggested that language may have evolved as the by-product of selection for other abilities or as a consequence of as-yet unknown laws of growth and form. Others have argued that a biological specialization for grammar is incompatible with every tenet of Darwinian theory – that it shows no genetic variation, could not exist in any intermediate forms, confers (...) no selective advantage, and would require more evolutionary time and genomic space than is available. We examine these arguments and show that they depend on inaccurate assumptions about biology or language or both. Evolutionary theory offers clear criteria for when a trait should be attributed to natural selection: complex design for some function, and the absence of alternative processes capable of explaining such complexity. Human language meets these criteria: Grammar is a complex mechanism tailored to the transmission of propositional structures through a serial interface. Autonomous and arbitrary grammatical phenomena have been offered as counterexamples to the position that language is an adaptation, but this reasoning is unsound: Communication protocols depend on arbitrary conventions that are adaptive as long as they are shared. Consequently, language acquisition in the child should systematically differ from language evolution in the species, and attempts to analogize them are misleading. Reviewing other arguments and data, we conclude that there is every reason to believe that a specialization for grammar evolved by a conventional neo-Darwinian process. (shrink)

Two opposing accounts of early language evolution, the compositional and the holistic, have become the subject of lively debate. It has been argued that an evolving compositional protolanguage would not be useful for communication until it reached a certain level of grammatical complexity. This paper offers a new, discourse-oriented perspective on the debate. It argues that discourse should be viewed, not as a level of language structure ‘beyond the sentence’, but as sequenced communicative behaviour, typically but not uniquely involving language. (...) This provides for continuity from exchanges making use of simple communicative resources such as single words and gestures to those making use of complex grammatical conventions. Supporting evidence comes from child language and from original experiments with adults using constrained language systems. The paper shows that the utility of emerging compositional language is not dependent on some critical level of complexity, and so defends the compositional account. (shrink)