Feedback valence affects auditory perceptual learning independently of feedback probability

Abstract

Previous studies have suggested that negative feedback is more effective in driving learning than positive feedback. We investigated the effect on learning of providing varying amounts of negative and positive feedback while listeners attempted to discriminate between three identical tones; an impossible task that nevertheless produces robust learning. Four feedback conditions were compared during training: 90% positive feedback or 10% negative feedback informed the participants that they were doing equally well, while 10% positive or 90% negative feedback informed them they were doing equally badly. In all conditions the feedback was random in relation to the listeners' responses (because the task was to discriminate three identical tones), yet both the valence (negative vs. positive) and the probability of feedback (10% vs. 90%) affected learning. Feedback that informed listeners they were doing badly resulted in better post-training performance than feedback that informed them they were doing well, independent of valence. In addition, positive feedback during training resulted in better post-training performance than negative feedback, but only positive feedback indicating listeners were doing badly on the task resulted in learning. As we have previously speculated, feedback that better reflected the difficulty of the task was more effective in driving learning than feedback that suggested performance was better than it should have been given perceived task difficulty. But contrary to expectations, positive feedback was more effective than negative feedback in driving learning. Feedback thus had two separable effects on learning: feedback valence affected motivation on a subjectively difficult task, and learning occurred only when feedback probability reflected the subjective difficulty. To optimize learning, training programs need to take into consideration both feedback valence and probability.

Fig 1. Experimental design.

(A) The procedure consisted of a pre-test that included a short (5-trial) demonstration to familiarize listeners with the task, followed by a short (30 trials) probe to assess the difference limens for frequency (DLF) [34]. The training phase consisted of 600 trials delivered in 100-trial blocks, with a 10-minute break after the first 3 blocks. Following training, a second probe was administered to assess post-training DLFs. (B) Screenshots of the software used for testing and training. Separate groups were trained with 10% and 90% positive feedback (top; [30]), and 10% and 90% negative feedback (bottom). Note that the 10% positive and 90% negative feedback conditions (left column) are equivalent in informing participants that they are doing very badly, while the 90% positive and 10% negative feedback conditions (right column) are equivalent in informing participants they are doing very well.

Fig 2. Learning.

(A) Pre- and Post-training DLFs for each training group. The asterisk demarcates a significant difference between pre- and post-training DLFs (after correction for multiple comparisons). (B) Learning—the difference (in logs) between pre- and post-training DLFs for the groups receiving positive and negative feedback. Note that the percentages by the markers indicate the probability of feedback, while the abscissa denotes the meaning conveyed by the feedback. Error bars are s.e.m.