Dynamic aspects of auditory spatial attention

Erol Ozmeral, Virginia Best, Norbert Kopco, Christine Mason, Gerald Kidd Jr, and Barbara Shinn-Cunningham

Hearing Research Center, Boston University, Boston, MA, 02215, USA.

Spatial attention plays an important role when listening in complex auditory environments and can, for example, enhance the identification of a speech target embedded in a mixture. However, little is known about the dynamics of auditory spatial attention. In this study, we examined the impact of relatively rapid changes in target location on speech identification in a mixture.

Stimuli were presented from a five-loudspeaker array. On each trial, the listener�s task was to identify a sequence of four spoken digits that was presented either from a single location (fixed condition) or from a location that changed randomly from digit to digit (switching condition). For each position in the sequence, interfering digits occurred simultaneously at the other four locations, and a visual cue indicated where the target was located. The rate of presentation was varied by inserting silent delays between digits of 0, 250, 500 or 1000 ms.

Performance in the switching condition was always poorer than in the fixed condition, as a result of at least two factors: (1) a cost associated with switching locations at rapid rates of presentation, and (2) a loss of refinement of selectivity throughout the sequence that is observed when the location is fixed.

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