Which attention is needed for implicit sequence learning?

The role of attention in implicit sequence learning was investigated in 3 experiments in which participants were presented with a serial reaction time (SRT) task under single- or dual-task conditions. Unlike previous studies using this paradigm, these experiments included only probabilistic sequences of locations and arranged a counting task performed on the same stimulus on which the SRT task was being carried out. Another sequential contingency was also arranged between the dimension to be counted and the location of the next stimulus. Results indicate that the division of attention barely affected learning but that selective attention to the predictive dimensions was necessary to learn about the relation between these dimensions and the predicted one. These results are consistent with a theory of implicit sequence learning that considers this learning as the result of an automatic associative process running independently of attentional load, but that would associate only those events that are held simultaneously in working memory.