ABSTRACT
Discrimination may be either successive or simultaneous, depending on whether the discriminated stimuli are present successively or simultaneously, respectively. Successive discriminations are produced by multiple schedules. The schedule operating during each stimulus in a multiple schedule controls a rate and pattern of responding that is characteristic of that schedule operating in isolation, or as a single schedule. A strong interaction called behavioural contrast develops between the components of multiple schedules. A stimulus generalization gradient is a functional relationship between the strength or probability of a response to a given stimulus and the similarity of that stimulus to a stimulus to which an individual was exposed during either operant or respondent conditioning. Behavioural momentum is the product of response rate and resistance to change. Discrimination training can be enhanced by procedures that occur before or during it. With both successive and simultaneous discriminations, a process of fading minimizes errors and facilitates rapid development of the discrimination.
