Characteristics and response-displacement effects of shock-generated responding during negative reinforcement procedures: pre-shock responding and post-shock aggressive responding.
Shock produces both escape and aggression, but extra response options can steer the animal toward the safer one.
01Research in Context
What this study did
Hake et al. (1972) worked with pigeons on a fixed-interval schedule. Shock came every 60 seconds unless the bird pecked a key. The setup gave two side keys as well. One key produced food, one let the bird attack a fake target, and the center key turned off shock.
The team wanted to see which responses shock pulled out on its own. They watched birds before and after each shock. They also looked at whether having extra keys changed where the birds directed their behavior.
What they found
Shock created two clear response chunks. Just before shock, birds pecked the escape key hard. Right after shock, they bit the attack target. When the attack key was there, biting stayed high. When it was gone, birds switched to pecking the food or escape key.
The study showed shock itself drives both escape and aggression. Giving other topographies let the birds swap one for the other.
How this fits with other research
Vukelich et al. (1971) found the same lab one year earlier. They showed low-intensity frequent shock cut biting, while high-intensity rare shock raised it. Hake et al. (1972) add the twist: simply adding a non-aggressive key pulls responses away from biting even when shock is strong.
Azrin (1970) used punishment to stop shock-elicited biting. Hake et al. (1972) reach a similar end without extra punishment; they just give the bird something else to do. The two papers sit side-by-side: one suppresses aggression by consequence, the other by displacement.
Last et al. (1984) came twelve years later. They showed shock can maintain its own responding through interresponse-time contingencies. Hake et al. (1972) set the stage by proving shock generates multiple response classes; G et al. show one of those classes can be kept alive by the shock itself.
Why it matters
When you run escape or avoidance programs, watch for shock- or timeout-elicited side behavior. Give your client two or three clear, easy responses. If problem behavior pops out right after the aversive event, try adding a functional alternative before you increase punishment. The 1972 birds teach us that topography is fluid; arrange the environment so the response you want is also the response that is easiest to emit.
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02At a glance
03Original abstract
Bar-pressing (Experiment I) or key-pressing (Experiments II and III) responses of monkeys were reinforced according to a fixed-interval schedule of negative reinforcement: the first response after a fixed interval of time terminated regularly spaced shocks for a fixed time designated as the reinforcement period. During extinction, shocks continued during the reinforcement period. That there were two types of responding generated by shock alone was indicated by (1) the level of responding maintained during extinction relative to conditions without shock, (2) the stability of two between-shock response patterns across reinforcement and extinction conditions, and (3) the development of these two between-shock patterns without a history of reinforcement. Subjects developed either a pre-shock or a post-shock response pattern when only the bar was available. However, when both a bite tube, an operandum requiring an aggressive topography, and a recessed key, an operandum that did not require an aggressive topography, were provided, the post-shock pattern was observed in tube biting and the pre-shock pattern was observed in key pressing. Removal of the bite tube produced post-shock key responding similar to that observed when only the bar was available. The displacement of post-shock, aggression-motivated responding confirmed the confounding effect of shock-generated responding in negative reinforcement procedures, and suggests that the use of concurrent response alternatives would reduce such confounding.
Journal of the experimental analysis of behavior, 1972 · doi:10.1901/jeab.1972.17-303