Punishment Generalization Gradients with Humans

Abstract

Electric-shock punishment produces stimulus-generalization gradients with animals. The purpose of the present experiments was to determine whether response-cost punishment produces similar gradients with humans. In Experiment 1, psychophysical procedures were used to generate a set of 10 horizontal lines that differ in length such that adjacent lines were indiscriminable, then reinforcement gradients were obtained with those lines to show that gradients can be produced with those stimuli. In Experiment 2, subjects pressed a lever for points exchangeable for money on a VI schedule in the presence of each stimulus, then points were lost immediately after each response in the presence of Stimulus 6 (the middle value). Response rate decreased in the presence of Stimulus 6, but it had a similar increase in the presence of all other stimuli. Those results suggest that point loss and not line length was the discriminative stimulus for further point loss. To minimize stimulus control exerted by immediate point loss, and thus enhance control by line length, in Experiment 3 points were lost only at the end of the component correlated with Stimulus 6, and in Experiment 4 point loss was arranged on VR and VI schedules. Neither delayed nor intermittent point loss produced gradients: Unpunished response rate was similar in the presence of all line lengths. The present results suggest that the technique of reinforcing responding in the presence of several stimuli during baseline then punishing responding in the presence of only one of those stimuli does not produce with humans and response-cost punishment the gradients obtained with pigeons and electric-shock punishment.