Spence's Theory Of Discrimination Training

In operant conditioning stimuli are associated with a reinforcer or punishment. Generalization occurs when an individual responds to similar stimuli in the same way and discrimination occurs when they respond to some stimuli but not others. Stimulus discrimination training refers to the strategy in which an individual is taught to engage in certain behaviors in the presence of particular stimuli. This type of training can either be conducted using classical or instrumental conditioning procedures. In instrumental conditioning procedures the stimulus that signals the availability of the reinforcement is referred to as the S+, while the stimulus that signals the lack of reinforcement is called the S-. The S+ and S- are called discriminative stimuli once they have successfully gained control of the behavior of an individual. The S+ is the discriminative stimuli for performing an instrumental response while the S- is the discriminative stimuli for not performing such a response. Dr. Kenneth W. Spence produced a theory of discrimination learning, which aimed to gain a better understanding on what is

In a training procedure called an intradimensional discrimination, the S+ and S- are similar except for one feature. Intradimensional discrimination can produce an event, which accounts for the theory of discrimination learning, known as the peak shift effect. The peak shift effect is a shift in the peak responding that moves from the original S+ in the direction away from the S-. This effect occurs when both the excitatory (S+) and inhibitory (S-) stimuli are conditioned and the inhibition changes the shape of the gradient. As a result, the maximum amount of responding occurs to a stimulus that was not previously trained as the S+. For example if the inhibitory stimulus (S-) is to the right, the peak shifts to the