Retrieval of a well-established skill is resistant to distraction: evidence from an implicit probabilistic sequence learning task

The characteristics of acquiring new sequence information under dual-task situations have been extensively studied until now. Performing such a concurrent task has often been found to affect performance. In real life, however, we mostly perform a secondary task when the primary one is already well-acquired. The effect of a dual-task on the ability to retrieve well-established sequence representations remains elusive. The present study investigated whether accessing a well-acquired probabilistic sequence knowledge is affected by a concurrent task. Participants acquired non-adjacent regularities in an implicit probabilistic sequence learning task. After a 24-hour offline period, we tested the participants on the sequence learning task under dual-task or single-task conditions. Here we show that although the dual-task condition significantly prolonged the overall reaction times in the primary task, the access to the previously learned probabilistic representations remained intact. Moreover, we found an inverse relationship between the ability to successfully retrieve sequence knowledge and the accuracy of the secondary task, which fits in well with the hypothesis of competition between model-based and model-free processes. Our results highlight the importance of studying the dual-task effect not only in the learning phase but also during memory access.