Imitation is a mechanism for the intergenerational transmission of acquired characteristics. Before explicit linguistic instruction, infants learn many of the skills, customs, and behaviour patterns of their culture through imitation. In imitating, infants use another's behaviours as a basis for their own, despite differences in body size, perspective of view, and modality through which self and other can be perceived. As ubiquitous and useful as imitation is, how imitation is accomplished poses one of the deeper puzzles in infancy.

Learning through imitation is a powerful and versatile method for acquiring new behaviors. In humans, a wide range of behaviors, from styles of social interaction to tool use, are passed from one generation to another through imitative learning. Although imitation evolved through Darwinian means, it achieves Lamarckian ends: it is a mechanism for the inheritance of acquired characteristics. Unlike trial-and-error-based learning methods such as reinforcement learning, imitation allows rapid learning.

We present a computational model that learns a coupling between motor parameters and their sensory consequences in vocal production during a babbling phase. Based on the coupling, preferred motor parameters and prototypically perceived sounds develop concurrently. Exposure to an ambient language modifies perception to coincide with the sounds from the language. The model develops motor mirror neurons that are active when an external sound is perceived. An extension to visual mirror neurons for oral gestures is suggested.

We propose an extension of the study of imitation in artefacts in which imitation takes place at the populationlevel.

‘Nature’/’Nurture ’ controversies have been perennial in the study of language, one of the oldest subjects of intellectual endeavor. The first half of this century saw us at the Nurture pole of the oscillation, the second half has placed us at the Nature pole. It would be desirable to escape this pendulum. The main current approach to ‘naturalizing ’ language is what I shall call ‘Simple Nativism’. It holds that both in form (syntax) and content (semantics) language is essentially innate. Syntax is governed by an innate ‘Universal Grammar’, and the ideas encoded are just elements of the ‘Language of Thought’. The problem with this approach is that it minimizes the very substantial differences between languages in both form and content. An alternative strategy for naturalizing language is coevolutionary theory, which conceives of culture as a self-replicating track of information parallel to, and interacting with, the genome, but with faster rates of adaptation and change. On this view, language is a hybrid biological/cultural phenomenon, and the human language ability has a built-in expectation of variation. In the body of the paper, I focus on the issue of whether the content of linguistic