Proceedings of the Annual Meeting of the Cognitive Science Society

The experiment reported in this paper provides evidence that there are at least two independent implicit learning mechanisms in implicit learning: an efficiency mechanism, which underlies changes in reaction time to patterned stimuli, and a conceptual fluency mechanism, which underlies the ability to make judgments about stimuli based on implicit knowledge. Each of these implicit mechanisms is independent of explicit learning. Subjects performed a serial reaction time task under one of three learning conditions (nonattentional, attentional and observational) for one of three study lengths (2, 6 or 12 blocks). Subjects then completed five tests of their knowledge: attentional and nonattentional reaction time tasks (measuring two kinds of efficiency learning), awareness questionnaire (measuring explicit knowledge) , a generation task, and a conceptual fluency task. Correlation analyses and criterion analyses found no dependencies between the measures in low awareness subjects. In addition, the measures were influenced differently by the independent variables of learning condition and study length; these dissociations indicate separate underlying mechanisms. Implications of the existence of multiple implicit mechanisms for connectionist modeling of implicit learning are drawn.