Individual differences and the fundamental similarity of implicit and explicit adult second language learning

This study examines evidence for the claims of Krashen (1981, 1985) and Reber (1989, 1993; Reber, Walkenfield & Hernstadt, 1991) that unconscious learning under Implicit and Incidental conditions is insensitive to measures of individual differences in cognitive abilities, in contrast to learning under conscious Rule-search and Instructed conditions. I assessed individual differences between 104 learners of English as a second language using two subtests of the Modern Language Aptitude Test (Carroll & Sapon, 1959). Following the participants' exposure to sentences illustrating easy and hard second language rules during training, I assessed their learning through a grammaticality judgment test. I assessed rule awareness on the basis of responses to a debriefing questionnaire which asked if learners had noticed rules, were looking for rules, and could verbalize the rules. Only in the Incidental condition was the extent of learning and awareness unrelated to individual differences in aptitude. Awareness at the level of Noticing did not accompany superior learning in any condition, but at the level of Looking for Rules, awareness accompanied superior learning for Implicit learners. At the level of Ability to Verbalize, awareness accompanied superior learning for both Implicit and Rule-search learners.