Sensory reinforcement using paired stimuli from different modalities

Abstract
The effects of the concurrent presentation of two sensory changes contingent upon a bar pressing response of rats were investigated. Initially, a performance asymptote was established with one sensory reinforcer after which a second sensory reinforcer was added. When an asymptotic performance level was reached with the paired sensory reinforcers, one was deleted. The addition of a second sensory change initially produced a marked increase in the response rate. This rate declined to a new and only marginally elevated asymptote in subsequent trials. It was suggested that an early summation in the reinforcing effectiveness of two combined sensory changes gives way to a later interaction in their reinforcing effectiveness.