What are the cognitive correlates and components of learning, and to what extent are these affected by instructional manipulations, and different learning conditions? Answers to these questions concerning the influence of cognitive learner variables on second language acquisition (SLA), and on the development of effective second language (SL) instruction, are a subject of major interest to both SLA researchers and those involved in SL pedagogy alike. Cognitive theory has influenced SLA theory and SL pedagogy in the past, for example through the work of such researchers as Carroll (1962, 1990), on the measures of cognitive ability predicting aptitude for language learning; Lado (1965) and Stevick (1976), on the role of memory in language learning; McLaughlin (1965, 1987), on information processing approaches to SLA theory; O'Malley and Chamot (1990), on learning strategies; and Krashen (1982), on the role of consciousness during instructed and naturalistic SLA.

More recently, both theoretical research into SLA and SL pedagogy have shown renewed interest in the role of cognitive variables. Articles on attention, memory, and automaticity, as well as on connectionism, learnability and language processing have increasingly appeared in the major SLA journals in the field, reflecting in part the rapid pace of development of the relatively new fields of cognitive science and cognitive psychology, and research findings arising within them.