Auditory sequence learning: differential sensitivity to task relevant and task irrelevant sequences

Using a serial reaction time task, this study examines whether learning of auditory sequences is possible without a corresponding motor response, i.e., by listening alone. The dual sequence paradigm used by Mayr (in Journal of the Experimental Psychology: Learning memory and cognition 22:350-354, 1996, Experiment 1) was adapted to the auditory domain. Four different actors spoke the same four colour words. These were presented such that speaker identity followed one sequence, and the word spoken followed a different sequence. Subjects were asked to respond (with a key press) to one of these dimensions (identity or word), and ignore the other. Results showed learning for either type of stimulus, but only when it was responded to. No learning of either type of auditory sequence by listening alone was found. The results add evidence to visual implicit learning studies that have failed to find learning of event sequences when spatial or response selection was not an important factor in processing. The findings are discussed in the context of implicit learning as a general and fundamental cognitive process.