Reber, Sanchez, & Fraser – CNS 2011
Consolidation in implicit sequence learning: Retroactive interference effects modulated by concomitant explicit knowledge
Paul J. Reber1, Daniel J. Sanchez1, David Fraser2;1Northwestern University, 2Chatham University
Memory consolidation is a vital process by which knowledge representations become stable and long-lasting. While well-studied in declarative memory, implicit skill learning also appears to undergo a consolidation process after the training period. Immediately after learning a new motor sequence, knowledge may be vulnerable to retroactive interference from learning of another novel sequence. To assess whether retroactive interference is observed during implicit perceptual-motor sequence learning, participants learned three different 12-item second-order conditional sequences over two sessions using the Serial Interception Sequence Learning (SISL) task. In the SISL task, cues scroll vertically towards targets on a computer screen. Participants attempt to press a corresponding key when a cue reaches its target zone. During the first session participants trained on a first sequence (A), which was immediately followed by training on a second sequence (B). Either 24 or 48 hours later, participants returned for a second session and trained on a third sequence (C), followed by tests for implicit and explicit sequence knowledge for all three sequences. Retroactive interference for sequence A was observed in participants who had low explicit knowledge of sequence A, but not in participants with high explicit knowledge. No interference was observed for sequence B, for which there was a substantial delay period prior to learning sequence C. These results suggest that implicit sequence learning requires a consolidation period to avoid retroactive interference, but this interference effect can be ameliorated by concomitant explicit sequence knowledge.
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