Perceptual and procedural learning in interaural cue discrimination

Abstract

Training in stimulus detection, discrimination, or identification generally leads to an improvement in performance, apparently in two phases. Learning during the early, rapid phase (within hours) has been attributed predominantly to procedural or task learning. Perceptual (true stimulus) learning is believed to occur mainly in the slower, later phase. Two experiments were undertaken to determine whether significant perceptual learning also occurs during the early phase. In the first, four groups of listeners were trained for 1 h in interaural level difference (ILD) discrimination. Stimuli were presented within a different, two- or three-interval task for each group. The following day, complete generalization of learning from the trained to the untrained tasks was demonstrated. In the second experiment, two groups of listeners were trained in an ILD discrimination task. In one group the stimulus was at a fixed, suprathreshold level (ILD=15 dB), and in the other the stimulus was varied adaptively around the listener’s discrimination threshold. The post-train mean stimulus discrimination threshold in the suprathreshold group was 3.9 dB, and in the threshold group was 2.4 dB (p<0.01). These findings suggest perceptual learning contributes significantly to the early, rapid phase of performance improvement in interaural cue discrimination.