Language Acquisition as Rational Contingency Learning

This paper considers how fluent language users are rational in their language processing, their unconscious language representation systems optimally prepared for comprehension and production, how language learners are intuitive statisticians, and how acquisition can be understood as contingency learning. But there are important aspects of second language acquisition that do not appear to be rational, where input fails to become intake. The paper describes the types of situation where cognition deviates from rationality and it introduces how the apparent irrationalities of L2 acquisition result from standard phenomena of associative learning as encapsulated in the models of Rescorla and Wagner (1972) and Cheng and Holyoak (1995), which describe how cue salience, outcome importance, and the history of learning from multiple probabilistic cues affect the development of ‘learned selective attention’ and transfer. This article considers how fluent language users are rational in their language processing, rational in the sense that their unconscious language representation systems are optimally prepared for comprehension and production. In this view, language learners are intuitive statisticians, weighing the likelihoods of interpretations and predicting which constructions are likely in the current context, and language acquisition is contingency learning, that is the gathering of information about the relative frequencies of form‐function mappings. These arguments are well supported by the psycholinguistic evidence relating to first language. But there are important aspects of second language acquisition that do not appear to accord with this characterization, those aspects where despite massive experience of naturalistic input and usage, the system fails to become optimally tuned to represent the second language forms, their functions, and their contextualized likelihoods of occurrence. The article builds the framework for an explanation of the seeming irrationalities of L2 acquisition in terms of standard phenomena of associative learning involving ‘learned selective attention.’ In order to place L1 and L2 in the context of a rational analysis of language learning, I first illustrate the problem by considering the design of word processors of a more mechanical kind than is the ultimate goal of our inquiry. Having thus set a concrete stage, I outline the process of the rational analysis of learning and memory (Anderson 1989, 1991b; Anderson and Milson 1989; Anderson and Schooler 2000). Next I describe some statistical