Auditory spatial attention influences discrimination of interaural time differences: Evidence from a probe-signal paradigm

Abstract

Performance on a same–different ITD discrimination task was used as a metric for auditory spatial attention. In several variants of a probe-signal procedure, attention was directed as detailed below. In all experiments, performance was better for signals lateralized on the expected side of the head. In experiment 1, a lateralized auditory cue preceded the signal. Lest this functioned not simply as an attentional cue but also as a spatial landmark, experiment 2 used no cue but manipulated expectation by presenting trials more frequently on a particular side. To establish whether the effects in experiment 2 generalized to all sounds within the spatial focus or were attributable simply to greater familiarity with the expected stimulus, a rove was incorporated in the pitch (experiment 3) or the timbre (experiment 4) of the signals on each trial. Experiment 5 introduced trial-by-trial visual cueing which, necessarily endogenous, provided evidence for top–down attentional control. Further work established whether analogous effects are seen on a frequency discrimination task, and when sounds are lateralized by IID. [Work supported by UK BBSRC.]