Scalar expectancy

The scalar timing or scalar expectancy theory (SET) is a model of the processes that govern behavior controlled by time. The model posits an internal clock, and particular memory and decision processes. SET is one of the most important models of animal timing behavior. The scalar timing or scalar expectancy theory (SET) is a model of the processes that govern behavior controlled by time. The model posits an internal clock, and particular memory and decision processes. SET is one of the most important models of animal timing behavior. John Gibbon originally proposed SET to explain the temporally controlled behavior of non-human subjects. He initially used the model to account for a pattern of behavior seen in animals that are being reinforced at fixed-intervals, for example every 2 minutes. An animal that is well trained on such a fixed-interval schedule pauses after each reinforcement and then suddenly starts responding about two-thirds of the way through the new interval. (See operant conditioning) The model explains how the animal's behavior is controlled by time in this manner. Gibbon and others later elaborated the model and applied it to a variety of other timing phenomena.