9306283 Gallistel Understanding the processes that mediate choice in the face of uncertainty is fundamental to understanding foraging behavior in animals and economic behavior in humans. It has long been known that rats and humans tend to allot time or invest in a given course of action in proportion to the relative amount of reward they experience from it--the matching law. If one alternative yields twice as much reward as another, they spend twice as much time with that alternative. Dr. Gallistel has discovered that rats can assess the relative rates of reward based on the most recent one or two intervals between rewards. He now will explore how both the most recent and more long-range experience determines their choice statistics, primarily the statistics describing how long they stay with an alternative once they've chosen it. The rats are rewarded by direct electrical stimulation of a pathway in the brain. This artificial reward does not produce satiation (loss of motivation to respond), so animals may be given many rewards for long periods every day, generating the voluminous data required for analyzing the statistical laws that govern their choice behavior. Understanding the preverbal (animal) process for coping with choice in the face of uncertainty is relevant to estimating the role of language in mediating these same choices in humans. Because these experiments provide reward by direct electrical stimulation of neural tissue, they also open up the prospect of investigating the neurophysiological basis of this ubiquitous and important behavioral process. Thus, the study of matching behavior in self- stimulating rats may enrich our understanding of human-decision making on the one hand and open an avenue to the experimental study of the neurobiology of elementary decision-making on the other.
