A central issue of debate in linguistics is the nativist hypothesis: the proposal that universally observed features of languages can be explained by a universally shared and biologically determined cognitive substrate that strongly and transparently predicts these linguistic features (Chomsky, 1965 ). An evolutionary stance appears to provide support for this hypothesis (Pinker & Bloom, 1990) . However, language is underpinned by social learning and cultural transmission alongside biological

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... olution, and the interactions between these three systems are relatively poorly understood. We set out a general model of these interactions that leads to a surprising conclusion: cultural transmission renders the biological evolution of strong domain-specific innate constraints unlikely, but we nonetheless witness strong universal tendencies in the cultural systems of these simulated populations. In this talk, we present the results of a simple implementation of this model. The details of our approach are as follows. Our formalisation has a basis in three components: a rational framework for language acquisition, an iterated learning model of cultural transmission, and a representation of biological evolution. We assume language learners must identify which of two arbitrarily distinct language types, t 0 and t 1 , is most likely to have generated the linguistic output of a learner from the previous generation: an observed set of b utterances, d. Each language type is associated with a diagnostic utterance class u, such that P (u y |t y ) = 1 − and P (u y |t x =y ) = . Learners apply Bayes' rule to determine P (t y |d) on the basis of this likelihood function and a prior expectation for t y given by a prior distribution over language types, which is characterised by the parameter p, where P (t 1 ) = p and P (t 0 ) = 1 − p.