The conditioned reinforcing strength of redundant stimuli

In a test of the uncertainty reduction and conditioned reinforcement hypotheses, the effects of three procedures on right keypecking (observing) behavior of pigeons were compared in Experiment 1. In Experiment 2, a test of the delay-reduction hypothesis under the Redundant S super(+) and S super(-): Correlated procedure (from Experiment 1) was performed. In this case, a righ keypeck produced the "redundant" stimulus change only during the last 5 s of any component; at other times the right key remained white. The results of both experiments support the view that, of several copresent stimuli, the stimulus that is both nonredundant and correlated with positive reinforcement is the stronger conditioned reinforcer.