I review the classic literature in generative grammar and Marr's three-level program for cognitive science to defend the Evaluation Metric as a psychological theory of language learning. Focusing on well-established facts of language variation, change, and use, I argue that optimal statistical principles embodied in Bayesian inference models are…

If the basic operations hypothesis (EJ 184 227) is interpreted as a general principle governing acquisition of all movement rules, it may obscure the fact that children distinguish between unbounded and local rules. Error patterns support this distinction, lending credence to theories with separate status for the two rule types. (Author/RD)