The electrophysiological and behavioral effects of distractor discriminability on auditory selective attention

Yunxia Tong, Purdue University

Abstract

Three experiments were conducted to examine the electrophysiological and behavioral effects of distractor discriminability on auditory selective attention to targets. The experiments differed in the range of overlap between the relevant and irrelevant channels and in the number of targets and distractors presented in each channel. In each experiment, participants attended and discriminated targets in one channel (ear) while ignoring interspersed distractors in another channel (ear). Target discrimination was performed in a baseline condition and in a set of filtering conditions, a modified version of the paradigm used by Melara and Mounts (1994). Behavioral and event-related potential (ERP) measurements were made during task performance. Increased distractor variability caused poorer accuracy and slower reaction times relative to baseline, a result known as Garner interference (1974), which reflects the failure of selective attention to the relevant channel. Physiologically, distraction discriminability reduced the P3 response to targets, and increased the P2 response to distractors. Channel separation (Nd) did not change across conditions. These results suggested that Garner interference is caused by the diminished distinctiveness of target representations in working memory, as distractors activate a greater range of the task relevant continuum. A pattern of early long-lasting negativity to targets and later positivity to distractors suggested that auditory selective attention operates through two distinct processing mechanisms: an excitatory mechanism to relevant signals and an inhibitory mechanism to irrelevant signals.

Degree

Ph.D.

Advisors

Melara, Purdue University.

Subject Area

Physiological psychology|Cognitive therapy

COinS