Effects of different amounts of brief training and rest on the generalization of learning from interaural-level-difference to interaural-time-difference discrimination

Abstract

Training-induced improvements on perceptual skills can be enhanced by increasing the amount of training and by resting between training and testing. However, how these two factors affect the generalization of learning from a briefly trained condition to an untrained one is unknown. Here, listeners were trained on an interaural-level-difference (ILD) discrimination condition (4-kHz tones), then were tested for generalization to an interaural-time-difference (ITD) discrimination condition (0.5-kHz tones). The amount of training and the time between training and testing differed across four groups. Listeners tested 10 hours after training had significantly lower ITD discrimination thresholds than naive listeners (n=94), regardless of whether training lasted for 20 min (n=14) or 2 hs (n=11). Thus, when there was a long time between training and testing, learning generalized from ILD to ITD discrimination regardless of the amount of training. In contrast, listeners tested immediately after training on ILD discrimination showed generalization to ITD discrimination with 20 min (n=14), but not 2 h (n=14), of training, suggesting that without rest between training and testing, longer training disrupted generalization. Hence, increased training interfered with generalization from ILD to ITD discrimination for short, but not long, delays between training and testing. [Work supported by NIH.]