ABSTRACT

Operationally, one stimulus is assumed to be preferred to another if an animal behaviorally increases the probability of being stimulated by that stimulus over the probability of being stimulated by the other. In general, behavioral inferences about preferences or aversions are established on a relative basis, although marked preferences or aversions are easily identified. Increased or decreased stimulus access on the part of an animal can be achieved in a number of ways, such as by spending more or less time in the physical proximity to a stimulus or by increasing or decreasing sniffmg behavior in its presence. Despite the fact that preference paradigms have been used to infer discrimination, it should be emphasized that a lack of preference does not necessarily mean a lack of discrimination.