An ear asymmetry in learning gap detection

Abstract

Gap detection performance was tested in each ear of 56 normal hearing subjects using 300 ms wide-band (200–4000 Hz) unfrozen noise bursts. No ear asymmetry was observed in the gap detection thresholds. In subsequent studies of individual subjects in which the same noise burst was used in all trial (frozen noise) a progressive improvement in gap detection threshold was observed over a 20-day period for both ears. Over the 20-day period, however, a highly significant ear difference was observed in the learning curves of the two ears despite the fact that the right and left ears were tested on alternate trials. The ear asymmetry in gap detection was not present in the first few days for two subjects but became progressively more obvious as testing proceeded. The third subject exhibited an ear asymmetry on the first day's block of trials which increased only slightly over the 20-day period. The right-left asymmetry in learning gap detection in frozen noise is difficult to explain without postulating some (asymmetrical) central processing mechanism.