PERCEPTUAL LEARNING

the effects of past experience on sensory perceptions. An organism's readiness to learn is of primary importance to its survival, and this readiness depends largely on its perceptual skills. Perceptual skills are intimately involved in producing more effective responses to stimuli. Historically, perceptual learning has been the subject of vigorous debate. Although early Gestalt psychologists denied that learning modifies perceiving, that this occurs is now almost universally accepted. Research continues to examine the extent of modification and how modification occurs. There are two main schools of thought: discovery and enrichment. The discovery theory holds that learning makes one aware of stimuli one had previously overlooked. Enrichment refers to one's increased awareness and heightened response capabilities in the light of a learning experience. It is very possible that discovery and enrichment may simply describe different aspects of perceptual learning. One aspect of the enrichment thesis holds that learning determines how one interprets common spatial relationships. For example, one learns to assume that a plate remains circular even though it may appear elliptical when viewed from certain angles. In fact, say theorists, these kinds of assumptions are essential in reducing ambiguity for mature perceiving. In the laboratory, perceptual learning has been tested and measured by observing the effects of practice on perceptual abilities. Subjects are given various auditory, olfactory, and visual acuity tests. With practice, subjects improve their scores, indicating that perceptual abilities are not immutable but are modifiable by learning. Researchers have also discovered through studies with newborn animals and with laboratory subjects adjusting to prism-distorted vision that active, exploratory interaction with the environment greatly enhances perceptual learning. In studies of animal behaviour, the term perceptual learning is sometimes used to refer to those instances in which an animal learns to identify a complex set of stimuli that can be used to guide subsequent behaviour. Examples of such perceptual learning include imitation and observational learning, song learning in birds, and imprinting in birds and mammals. See learning.