Binaural Detection in a Sequential Detection Paradigm

Abstract

An extension of the work reported by this author at the Washington meeting, the present study examines sequential detection in two frequency regions assigned to separate earphone channels. The observer's task was to make yes-no decisions concerning the presence of a sinusoidal signal in each earphone channel. A sequential ordering of observation intervals between earphone channels existed for all experimental conditions. The frequency region to be monitored in the right ear was always 630 Hz. Eight experimental conditions were formed by varying whether the order of presentation of observation intervals across earphone channels was fixed or random, whether the frequency region assigned to the left ear was at 630 or 1400 Hz, and whether the Gaussian noise background across earphone channels was correlated or uncorrelated. All experimental conditions were evaluated relative to performance in corresponding single-channel conditions. Results observed include: (1) Knowledge of the presentation order of observation intervals had little effect on performance; (2) A much larger decrement in performance relative to single-channel performance was obtained with a correlated noise background when the frequency region assigned to each earphone channel was the same; no such difference existed when the frequency regions were different. (3) Performance in one channel was lower if a signal event occurred in the opposite channel.