The irrelevant sound effect: Testing the psychological effects of sequence predictability

We tested the hypothesis that expectancy-violation is key to understanding those conditions under which instrumental music disrupts immediate serial-recall. Using isochronic presentation of irrelevant-sound stimuli during encoding and retention, recall was found to be impaired following both piano-note sequences (Experiment 1) and pure-tone sequences (Experiment 2). However, whereas intervallic organisation was determinant for pure-tones (randomly-ordered frequencies caused recall impairment while repeated frequency or ascending-frequency sequences did not) there was no effect of intervallic organisation of piano-note sequences. When the to-be-ignored sequences were presented with random anisochrony, the disruptive effect was absent for both piano notes (Experiment 3) and pure tones (Experiment 4). It is proposed that the irrelevant sound effect can be explained in terms of stimulus specific expectancy violation.