Effects of Response Requirements and Reinforcement Probability on the Latency to Depress a Foot Treadle

Abstract

Some previous studies have shown response latency to be a relatively sensitive measure of the effects of many experimental manipulations. However, when key pecking is the required response topography, the effects on latency of the independent variable may be confounded by respondent influences. The present study attempts to separate operant from respondent influences on response latency by requiring pigeons to depress a foot treadle, a topography unlikely to have respondent components. Three pigeons responded under a multiple fixed-ratio fixed-ratio schedule of food delivery with a 5-s intertriai interval. For two subjects, the independent variable was the number of responses required in each component. For another subject, the probability of reinforcement associated with each component constituted the independent variable. In general, response latencies were found to be shorter to the stimulus associated with the smaller response requirement or greater probability of reinforcement. However, unlike previous findings, these results were obtained only after quite large differences between response requirements or reinforcement probability were arranged. Further, birds reliably pecked the stimulus key even when this response was not required for reinforcement.