Temporal Compounds Reveal Interaural Biases

Abstract

A temporal compound is a complex pattern associated with a sequence of brief (30-100 msec) acoustic events whose identity can be distinguished but whose order cannot be reported. In the present study, two frequency glides were concatenated to form a 400-msec temporal compound consisting of 10 40-msec glides. Fourteen young adults were asked to discriminate these temporal compounds in a same-different paradigm employing a dichotic probe technique. Results supported the hypotheses that same judgments of temporal compounds involve global, or right hemisphere, processing and that different judgments of temporal compounds involve analytical, or left hemisphere, processing. Event-related potential (ERP) data revealed an interaction between side attended (right or left) and type of judgment (same or different). Same stimuli presented from the left side elicited greater ERP responses than different stimuli presented from the left side; conversely, different stimuli presented from the right side elicited greater ERP responses than same stimuli presented from the right side. Reaction times showed the "fast-same" effect, consistently observed in this paradigm.