Response bias and differential outcomes effect in conditional discrimination with rats

Abstract

In order to assess the so called differential outcomes effect, two triads of rats were exposed to a two-choice conditional discrimination procedure. For rats assigned to the experimental group, correct responses after auditory and visual conditional signals were differentially reinforced with food pellets and drops of water, respectively. Food pellets and drops of water randomly reinforced correct responses for rats assigned to the control group. The global percentage of correct responses was higher for the experimental than for the control group, while local percentage of correct responses differed between conditional signals for rats in the experimental group only. Results are discussed in the context of the differential outcomes effect and interbehavioral psychology. It is concluded that under two-choice conditional discrimination procedures correlating signals and reinforcers favors the establishment of simple independent discriminations.