Recovery of responses during mild punishment

Pigeons were punished with mild shock for pecking during one of two components of a multiple schedule. They eventually recovered so that they pecked at the same rate during both components. In one experiment they were extinguished after recovering. When punishment was maintained during extinction, they extinguished faster during the punished, than during the unpunished component. When punishment was stopped during extinction, they extinguished faster during the unpunished than during the previously punished component. In another experiment, punishment was programmed first during neither of the two components, then during one, then during both, and finally during the other component. The extent of recovery decreased with each successive cycle. It is concluded that, if transient emotional states are ignored, reward and punishment are symmetrical in their effects.     

Punishment as a discriminative stimulus and conditioned reinforcer with humans

Mental hospital patients were reinforced for responding in a two-response operant situation. When a noise was used to punish one of the responses, all subjects shifted to the unpunished one. When the noise was then paired with positive reinforcement, the subjects responded to produce the noise. Also, a novel response was reinforced by noise in the absence of other reinforcers. This study with humans extends the findings of previous studies with animals in revealing how a punishing stimulus can acquire discriminative or conditioned reinforcing properties.     

Conditioned reinforcement in second-order schedules

Pigeons responded under a schedule in which food was presented only after a fixed number of fixed-interval components were completed. Two such second-order schedules were studied: under one, 30 consecutive 2-min fixed-interval components were required; under the other, 15 consecutive 4-min fixed-interval components were required. Under both schedules, when a 0.7-sec stimulus light was presented at completion of each fixed interval, positively accelerated responding developed in each component. When no stimulus change occurred at completion of each fixed interval, relatively low and constant rates of responding prevailed in each component; a similar result was obtained when a 0.7-sec stimulus change occurred at completion of each fixed interval except the one which terminated with primary reinforcement. The 0.7-sec stimulus correlated with food delivery was an effective conditioned reinforcer in maintaining patterns of responding in fixed-interval components despite low average frequencies of food reinforcement.