Abstract
Numerous studies have demonstrated that repeated practice can induce substantial improvements in performance on low-level visual perceptual tasks. However, such learning is characteristically difficult and slow, requiring many days of training. The purpose of this study was to investigate whether the addition of sound affects learning of a visual perceptual task. Therefore, we trained one group with an audiovisual coherent motion stimulus (dynamically moving dots of varying coherence in the visual modality, and directional moving sounds masked with varying amounts of white noise, in the auditory), and a second group with a unimodal visual stimulus, and compared visual learning across ten training sessions. The visual stimulus and the number of trials containing visual stimulus was identical in the two groups. As expected, observers in both groups showed improvements of visual sensitivity with training. The audiovisual group also showed auditory sensitivity improvements. A follow-up test confirmed that visual-sensitivity improvements were specific to the trained stimulus directions, and therefore likely due to low-level perceptual learning rather than higher cognitive factors such as task learning. Most importantly, we found (for trials containing only visual signals) a significant benefit of audiovisual training over the visual-alone training. While both groups achieved similar performance by the end of each session, sensitivity improvements were much better retained across sessions for the audiovisual groups. These results suggest that sound can indeed enhance perceptual learning of a visual task.