Auditory integration of bandpass filtered sentences

Abstract

Auditory integration is the ability to merge auditory inputs received from different channels into a single percept. The present experiments investigated auditory integration of speech using lists of filtered CUNY sentences. Within each set, separate filtering preserved either low-frequency or high-frequency spectral information. The three sets of bandwidths were 550–750 and 1650–2250 Hz; 550–800 and 1650–2350 Hz; and 550–850 and 1650–2450 Hz. Four conditions were tested for each set of bandwidths: (1) LF only: (2) HF only; (3) LF–HF monotic (LF and HF filtered sentences presented simultaneously to one ear); and (4) LF–HF dichotic (LF sentence presented to one ear, HF sentences presented simultaneously to the other ear). Scores in the single band conditions were near floor. Scores in the monotic conditions were significantly greater than would be predicted from an additive combination of the single band conditions (i.e., superadditive effects). Scores in the LF–HF dichotic condition were significantly less than those in the LF–HF monotic condition but were greater than those for either the LF-only or HF-only conditions. Taken together, these findings suggest that listeners are able to integrate information across two auditory channels but that this integration is less than optimal. Implications of these results for theories of sensory integration are discussed.