Adrenal and thymus weight loss in the food-deprived rat produced by random ratio punishment schedules.

Abstract

After initial regular reinforcement of a lever-pressing response with milk, 6 groups of food-deprived rats were exposed to a concurrent random ratio punishment procedure wherein each group continued to be rewarded but had a different probability of receiving a brief electric foot shock for each response. Response suppression increased with punishment probability, with marked drop in responding at the highest shock probabilities. After 22 hr. of exposure to these "conflict" schedules, autopsies revealed (a) that adrenal and thymus weights had decreased under intermediate levels of punishment probability, and (b) that no gastric ulceration occurred in any S. A second experiment confirmed these findings and also traced the time course of these effects.

An Interresponse Time Analysis of Variable‐ratio Punishment

“…In addition, the mean postshock IRT was greater than subsequent IRTs, even in cases where the response rate was greater than the previously unpunished baseline. A similar result was reported by Snapper, Schoenfeld, and Locke (1966). Further, the postshock IRT was directly related to shock intensity but not shock frequency.…”

“…For those subjects, the overall response rate increased over the previously unpunished baseline for one or more shock intensity conditions. This response-rate facilitation has previously been observed during intermittently scheduled response-contingent shock, when the shock schedule was fixed-interval (Appel, 1968), variable-interval (Filby & Appel, 1966), fixedratio (Sandler, 1964), or random-ratio (Snapper et al, 1966), and especially for relatively low shock intensities. In order to more closely evaluate response rate facilitation in the pres- ent experiment, consider first the overall IRT distributions during VRIO punishment.…”

“…Intermittent schedules of punishment occasionally result in rates of reinforced responding that are greater than the previously unpunished baseline rate (Appel, 1968;Filby & Appel, 1966;Sandler, 1964;Snapper, Schoenfeld & Locke, 1966). When electric shock is used as the punishing stimulus, response rate facilitation generally occurs at relatively low shock intensities.…”

Response suppression and recovery under some temporally defined schedules of intermittent punishment.

“…Certain considerations might have led one also to expect that the amount of response suppression would have been a direct function of punishment probability. The first consideration is the data of Snapper, Schoenfeld, and Locke (1966), which indicate that amount of suppression increases with increases in probability of punishment. However, Snapper et al delivered punishments according to random-ratio punishment schedules so that there was a covariation of frequency and probability of punishment.…”

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

“…Given a constant overall rate of shock presentation, the probability of shock per response is inversely related to the overall rate of responding: the higher the response rate, the less probable a particular response will be followed by shock. Research on punishment has demonstrated the degree of response suppression to be inversely related to punishment probability (e. g., Azrin, Holz, & Hake, 1963;Snapper, Schoenfeld, & Locke, 1966). To the extent Lag = 0 suppresses pressing to a lesser degree when implemented in the presence of a moderate rate of responding than in the presence of a lower rate, the relative efficacy of the IRT-punishment relation may be greater in the former than in the latter case.…”