The role of insight in perceptual learning: evidence from illusory contour perception

The distinction between gradual and abrupt improvement in performance is commonly made in behavioral studies of learning. The learning of perceptual and motor skills is often characterized by gradual, incremental improvement and is found not to generalize over stimulus manipulations such as change in retinal size or location. In contrast, marked improvement in performance can occur suddenly—a phenomenon that has been termed ‘‘insight.’’ Previously, insight has been studied in the context of problem solving and similar cognitive-level tasks. In this chapter, we use an illusory contours shape-discrimination task to present evidence that perceptual learning can exhibit characteristics of insight. Observers exhibited an abrupt, dramatic improvement in their performance, which resembled an incident of insight. At the same time, however, the improvement showed a degree of stimulus specificity that previously was thought to characterize incremental, gradual learning. This juxtaposition of abrupt and stimulus-specific improvement suggests that the dichotomy between the two forms of learning needs to be revised. This idea echoes Hebb (1949), who argued that the insight/incremental-learning dichotomy may be artificial and that the two forms of learning need to be addressed within a single theoretical framework. In terms of brain mechanisms, this means that all types of learning may involve interactions between low-level and high-level representations of the stimulus.