Food-deprived pigeons were given a series of trials in which half ended with response- independent food presentation and half without it. During a trial, pecking the key could change its color from white to green (S+) or red (S-), depending on whether food was programmed or not. In baseline conditions, pecks produced both stimuli (colors) on a 15-s variable-interval schedule. In two different conditions, tandem VI DRH was applied to produce either S+ or S-. Results showed that the tandem contingency resulted in a general decrease in the discriminative stimulus production, markedly to S+, but not to S-. The findings are consistent with the uncertainty-reduction model of conditioned reinforcement.
Observing Response; Conditioned Reinforcement; Delay-reduction Model; Uncertainty-reduction Model; Pigeons
