Auditory Working Memory Is Susceptible to Intrusions from Subsequent Sounds

As sounds unfold over time, listeners often need to relate successive events while keeping them distinct. Auditory working memory is susceptible to interference from subsequent sounds, yet whether resulting errors reflect distortion of the remembered target or intrusion of the intervening sound itself remains unclear. Although both mechanisms can produce similar average biases toward an intervening sound, they predict distinct distributions of reproduction errors. Recent advances in continuous pitch reproduction now allow us to test these predictions in audition. In two experiments, participants remembered a target tone over a brief delay and reproduced its pitch on a circular continuous-response scale. During the delay, an intervening tone was presented; participants either ignored it or judged its similarity to the target. We analyzed reproduction-error distributions with mixture modeling to distinguish systematic shifts in target-centred responses (i.e., distortion) from responses clustered around the intervening pitch (i.e., intrusion). The results showed that the error distributions were better accounted for by models incorporating responses centred near the intervening pitch (i.e., intrusion) than the models assuming continuous displacement of target-centred responses alone (i.e., distortion). Exploratory analyses suggested that the influence of task relevance of the intervening sound was associated with baseline memory precision: listeners with less precise baseline reproduction tended to show greater interference when told to explicitly compare the sounds. Together, these findings suggest that intervening sounds may do more than bias reports of remembered pitch. On some trials, the intervening sound may guide the final response in place of the target, even when task-irrelevant.