MAINTENANCE AND SUPPRESSION OF RESPONDING UNDER SCHEDULES OF ELECTRIC SHOCK PRESENTATION¹

Abstract

In squirrel monkeys previously trained under a continuous avoidance schedule, characteristic patterns of responding were maintained under a 3-min variable-interval schedule of shock presentation (response-produced shock). Responding in the presence of a periodically presented stimulus, the termination of which coincided with the delivery of a response-independent electric shock (Estes-Skinner procedure), was not reliably affected. When shocks followed every response during certain signalled portions of the session, and were presented under the variable-interval schedule during the rest of the session (multiple 1-response fixed-ratio, 3-min variable-interval schedule of shock presentation), responding was suppressed during the fixed-ratio component and maintained during the variable-interval component. Environmental consequences do not have immutable properties, and may either support or suppress behavior, depending on the schedule of presentation.

An Interresponse‐time Analysis of Responding Maintained by Schedules of Response‐produced Electric Shock

“…With few exceptions, however, reports have described only responding maintained by interval schedules of shock presentation. The result usually obtained when ratio schedules of shock presentation are studied is decreased responding or suppression, rather than maintenance, of responding (Branch & Dworkin, 1981;Kelleher & Morse, 1969;McKearney, 1972).…”

THE EFFECT OF TIMEOUT ON PERFORMANCE ON A VARIABLE‐INTERVAL SCHEDULE OF ELECTRIC‐SHOCK PRESENTATION1

“…After Phases I and II, Monkeys BB and HB were retrained under a continuous shock-avoidance schedule (Sidman, 1953) of S-S 10, R-S 30 for 10 sessions. Subsequently, the animals were exposed to a training sequence resembling McKearney's (1972): concuirrent avoidance, fixed-time (FT) 10-min shock; FT 10-min shock alone; concurrent avoidance, VI 3-min response-produced shock; VI 3-min response-produced shock alone. Intervals comprising the VI schedule were identical to those used by McKearney (1972).…”

“…Subsequently, the animals were exposed to a training sequence resembling McKearney's (1972): concuirrent avoidance, fixed-time (FT) 10-min shock; FT 10-min shock alone; concurrent avoidance, VI 3-min response-produced shock; VI 3-min response-produced shock alone. Intervals comprising the VI schedule were identical to those used by McKearney (1972). Shock intensity (5.0 mA) and duration (30 msec) were held constant throughout this sequence.…”

“…Response rate decreased when timeout duration was decreased, and responding ceased wheni timeout was eliminated. These results in(licate that under certain conditions, a shock-free period following each response-produced shock is necessary to maintain responding.Recent studies have demonstrated that animals with specific types of behavioral hiistories will continue to respond when the only consequence of responding is the occasional presentation of a brief, intense electric shock (Byrd, 1969(Byrd, , 1972Kelleher and Morse, 1968;McKearney, 1968McKearney, , 1969McKearney, , 1970McKearney, , 1972Morse, Mead, and Kelleher, 1967;Stretch, Orloff, and Dalrymple, 1968; Stretclh, Orloff, and Gerber, 1970 ation of the traditional distinction between "positive" and "negative" reinforcers, i.e., between events such as food, whose onset normally acts as a reinforcer, and electric shock, whose offset normally acts as a reinforcer.In some studies that have demonstrated maintained responding on schedules of response-produced shock, both shock and a period of time relatively free from shock were contingent on responding: the typical, periodic (fixed-interval) schedules generated discontinuous response rates, with the animals pausing for about half the fixed-interval before responding resumed. This pause may be taken as an indicator of a "functional timeout".…”

“…Recent studies have demonstrated that animals with specific types of behavioral hiistories will continue to respond when the only consequence of responding is the occasional presentation of a brief, intense electric shock (Byrd, 1969(Byrd, , 1972Kelleher and Morse, 1968;McKearney, 1968McKearney, , 1969McKearney, , 1970McKearney, , 1972Morse, Mead, and Kelleher, 1967;Stretch, Orloff, and Dalrymple, 1968; Stretclh, Orloff, and Gerber, 1970 ation of the traditional distinction between "positive" and "negative" reinforcers, i.e., between events such as food, whose onset normally acts as a reinforcer, and electric shock, whose offset normally acts as a reinforcer.…”