AUDITORY AND VISUAL LOCALIZATION PERFORMANCE IN A SEQUENTIAL DISCRIMINATION TASK

Four subjects were tested in a two-alternative, forced-choice, three d own-one up adaptive paradigm in which two 200-ms signals were presente d sequentially with a 200-ms interstimulus interval. The subject's tas k was to indicate whether the second stimulus was to the right or left of the first. Tests were conducted with 57 dB (A-weighted), 1.0-kHz h igh-pass noise, the minimum audible angle (MAA) task, and with lights emitting 620 nm at a luminance level of 200 mL, the minimum visible an gle (MVA) task. Localization performance in the MAA task was equal to or better than that obtained in the MVA task for all regions of the fr ontal field with only one exception, presentations at 0-degrees azimut h. The implications of these results are discussed.