FIXED‐INTERVAL SCHEDULES OF ELECTRIC SHOCK PRESENTATION: EXTINCTION AND RECOVERY OF PERFORMANCE UNDER DIFFERENT SHOCK INTENSITIES AND FIXED‐INTERVAL DURATIONS¹

Abstract

In squirrel monkeys responding under a schedule in which responding postponed the delivery of electric shock, the presentation of response-dependent shock under a fixed-interval (FI) schedule increased the rate of responding. When the schedule of shock-postponement was eliminated, so that the only shocks delivered were those produced by responses under the FI schedule, a pattern of positively accelerated responding developed and was maintained over an extended period. When responses did not produce shocks (extinction), responding decreased. When shocks were again presented under the FI schedule, the previous pattern of responding quickly redeveloped. In general, response rates were directly related to the intensity of the shock presented, and inversely related to the duration of the fixed-interval. These results raise fundamental questions about the traditional classification of stimuli as reinforcers or punishers. The basic similarities among FI schedules of food presentation, shock termination, and shock presentation strengthen the conclusion that the schedule under which an event is presented and the characteristics of the behavior at the time the event is presented, are of overriding importance in determining the effect of that event on behavior.

A test of the Wagner-Rescorla model’s prediction of no response decrement in a nondifferential following a differential schedule of reinforcement

“…When US presentations in extinction retard the rate of response cessation relative to that rate obtained with CS-alone extinction, as has been demonstrated most powerfully for avoidance and escape responses (Coulson, Coulson, & Gardner, 1970;Fowler, 1971;Kelleher, Riddle, & Cook, 1963;McKearney, 1969;Stretch, Orloff, & Dalrymple, 1968) but also for conditioned suppression (Ayres & DeCosta, 1971) and leverpressing (Rescorla & Skucy, 1969) in rats, an explanation in terms of the adventitious temporal contiguity of response and reinforcement (Skinner, 1948) is probably most common. Other investigators have emphasized the discriminative properties of reinforcement (Rescorla & Skucy, 1969;Uhl, 1973;Zeiler, 1968).…”

Interresponse‐time Punishment: A Basis for Shock‐maintained Behavior

“…Following response acquisition under responsecontingent schedules of food presentation (e.g., Kelleher & Morse, 1968), shock postponement (e.g., McKearney, 1969), or response induction by periodic response-independent shock (e.g., Morse, Mead, & Kelleher, 1967; see Hutchinson, 1977, for a review), lever pressing of squirrel monkeys can be maintained by shock presentation under interval schedules, which present shock following the first response after a specified temporal interval (see Morse & Kelleher, 1977, for a review). But when shock is delivered under ratio schedules, that is, following a specified number of responses, pressing typically is suppressed, even when the number of responses per shock is matched to a preceding condition in which responding was maintained under an interval schedule (Branch & Dworkin, 1981).…”

The effects of response-contingent and noncontingent shock on free operant avoidance

“…The superirnposition of response-contingent shock has led to a decrease in response rate when every response was punished (PoweIl & Morris, 1969) and when additional shocks were programmed on fixed-ratio (FR) schedules (Sandler, Davidson, & Holzschuh, 1966; Mclntire et al, 1968), but to an increase in responding when programmed on fixed-interval (FI) schedules (McKearney, 1969).higher shock rate prevailing in this component of the schedule: high shock rate may lead to a decrease in responding but low shock rate to an increase. Using rats, Mclntire et al (1968) found that a FR schedule of response-contingent shock led to a decrease in responding of an avoidance baseline whereas the same rate of noncontingent shock increased responding.…”

“…The superirnposition of response-contingent shock has led to a decrease in response rate when every response was punished (PoweIl & Morris, 1969) and when additional shocks were programmed on fixed-ratio (FR) schedules (Sandler, Davidson, & Holzschuh, 1966; Mclntire et al, 1968), but to an increase in responding when programmed on fixed-interval (FI) schedules (McKearney, 1969).…”

“…The initial findings of Sidman, Herrnstein, & Conrad (1957) that response rate increases when noncontingent shocks are added to an avoidance schedule have been confirmed several times, e.g., Kelleher, Riddle, & Cook (1963), and McIntire, Davis, Cohen, & French (1968). The superirnposition of response-contingent shock has led to a decrease in response rate when every response was punished (PoweIl & Morris, 1969) and when additional shocks were programmed on fixed-ratio (FR) schedules (Sandler, Davidson, & Holzschuh, 1966;Mclntire et al, 1968), but to an increase in responding when programmed on fixed-interval (FI) schedules (McKearney, 1969).…”