SOME DETERMINANTS OF INHIBITORY STIMULUS CONTROL¹

Abstract

Interspersed reinforcement and extinction during discrimination learning generate a U-shaped gradient of inhibition about the stimulus correlated with extinction. The present work showed that extinction is not a necessary determinant of inhibitory stimulus control. In Exp. I, a reduction in the rate of reinforcement, through a shift from a multiple variable-interval 1-min variable-interval 1-min schedule to a multiple variable-interval 1-min variable-interval 5-min schedule, resulted in a post-discrimination line orientation gradient of inhibition about the stimulus correlated with the variable-interval 5-min schedule. In Exp. II, the rates of reinforcement, correlated with a pair of stimuli, were held constant during a shift from a multiple variable-interval 1-min variable-interval 1-min schedule to a multiple variable-interval 1-min differential-reinforcement-of-low-rate schedule. Inhibitory stimulus control about the stimulus correlated with the differential reinforcement of low rate was obtained. In both experiments, a reduction in the rate of responding during one stimulus and behavioral contrast during the other stimulus preceded the observation of inhibitory stimulus control.

Choice responding following multiple schedule training

“…He interpreted this result to mean that the stimulus associated with the VI 300-sec schedule had become inhibitory in relation to the VI 6O-sec stimulus. Weisman (1969) reported inhibitory gradients around a multiple schedule stimulus associated with the longer mean interreinforcer interval, supporting Guttman's suggestion. In the present choice procedure, there may be tendencies to both approach the stimulus associated with the smaller mean interreinforcer interval or the longer duration and to avoid the other stimulus because of its inhibitory properties.…”

“…This would account for the increase in choice slope over schedule slope. Note that Guttman's (1959) proposal of inhibitory effects comes not from an examination of his schedule results, but from the outcome of a transfer procedure, and the same is true for Weisman (1969) and ourselves. The choice procedure may provide a method for the future quantification of the proposed inhibitory effect.…”

The Effect of Negative Stimulus Presentations on Observing‐response Rates

“…However, presentations of S-introduce a number of changes in the procedure that are not intrinsic to the S -as a signal for the absence of reinforcement. These factors are discussed briefly below (see also Mueller, 1981) (Terrace, 1968;Weisman, 1969Weisman, , 1970. However, it was rejected on the basis of data showing that behavioral contrast did not occur when rates were lowered by a different method (Halliday & Boakes, 1972 4.…”

Behavioral contrast and inhibitory stimulus control

“…Generalization gradients indicated inhibitory control by the stimulus associated with EXT or VI 5-min for 19 of 20 subjects even though some subjects did not show contrast. These results question the presumed relationship between behavioral contrast and inhibitory stimulus control.It has been suggested (Farthing & Hearst, 1958;Terrace, 1966Terrace, , 1968Terrace, , 1971Weisman, 1969;Yarczower, 1970) that the OCCurrence of behavioral contrast is a necessary antecedent for the development of inhibitory stimulus control. For example, Weisman (1969) reported V-shaped postdiscrimination generalization gradients (a presumed correlate of inhibitory stimulus control) around a stimulus associated with a variable-interval (VI) 5-min schedule of reinforcement for only those subjects exhibiting behavioral contrast during multiple (mult) VI l-min VI 5-min discrimination training.…”

“…For example, Weisman (1969) reported V-shaped postdiscrimination generalization gradients (a presumed correlate of inhibitory stimulus control) around a stimulus associated with a variable-interval (VI) 5-min schedule of reinforcement for only those subjects exhibiting behavioral contrast during multiple (mult) VI l-min VI 5-min discrimination training.…”