Directing attention in pitch and time: Effects on the perception of hidden melodies

Abstract

Listeners attended to a target tone in the middle of a familiar melody that was interleaved with distractor notes. The target occurred in either expected or unexpected locations in pitch or in time. Expectancy was controlled by means of a cue melody preceding the embedded target. In half the sessions, the cue indicated the pitch level of the target, and listeners judged the time at which it occurred. In the other sessions, the cue indicated time, and listeners judged pitch. The cue was 83% valid, and expected targets matched the cue while unexpected targets did not. Rate of presentation was adjusted within each session to produce approximately 80% accuracy. Temporal expectancies had a much greater effect on reaction times (RTs) than did pitch expectancies. RTs for pitch judgments were about 130 ms longer when targets occurred at unexpected (versus expected) times, while RTs for time judgments were only about 25 ms longer for targets at unexpected (versus expected) pitches. Rhythmic organization provides a basis for the listener to direct attention to critical events in a rapid auditory stream.