Attention and the build-up of auditory stream segregation

• Published in: The Journal of the Acoustical Society of America 2000-05, Vol.107 (5_Supplement), p.2882-2882
• Main Authors: Carlyon, Robert P., Cusack, Rhodri, Foxton, Jessica M., Robertson, Ian H.
• Format: Article
• Language: English
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.428707

In the baseline condition of experiment 1, subjects were presented with a repeating ABA–ABA sequence of 125-ms tones in their left ear, and indicated, throughout the entire 20-s sequence, whether they heard one or two streams. The proportion of ‘‘two stream’’ responses increased during the course of each sequence. This build-up of stream segregation was greatly reduced when, for the first 10 s of each sequence, subjects performed a competing task on a train of noise bursts presented to the right ear. The competing task involved identifying the amplitude envelope of each noise burst as either rising or falling. The noise bursts had no effect in a third condition, in which subjects were instructed to ignore them. Experiment 2 showed that a substantial build-up of streaming can still be observed when subjects switch tasks halfway through the tone sequence, provided that both tasks require them to continually attend to the tones. We conclude that attention is crucial for the build-up of stream segregation, and that our results are inconsistent with models of streaming based purely on peripheral, ‘‘automatic’’ neural mechanisms.