Language contact plays a key part among the factors leading to change in grammars, and yet the study of syntactic change, especially in the generative or innatist tradition, has tended to neglect the role of contact in this process. At the same time, work on contact-induced change remains largely descriptive, with theoretical discussion restricted mostly to the putative limits on borrowing. This article aims at moving beyond these restrictions by outlining a psycholinguistically-based account of some of the ways in which contact leads to change. This account takes Van Coetsem's (1988, 2000) distinction between recipient-language and source-language agentivity as its starting point, building on this insight in the light of work on language acquisition and first language attrition, and showing how these principles can be integrated into a unified acquisitionist model of syntactic change in general. The model is then applied to case studies of contact-induced syntactic change in Yiddish and Berber.