Background: The objective of the present study was to compare both the acquisition speed and the resistance to extinction of a simple discrimination in pigeons, depending on whether the reinforcing consequence included different conditioned reinforcer stimuli or always the same.
Method: The study was conducted with four experimentally naive female pigeons, which were trained to respond to a “go-no go” procedure in four Skinner boxes with coupled touchscreens. The subjects were divided into two conditions with two subjects each. In the Experimental condition, the reinforcement of correct trials was performed by the presentation of one of four previously trained conditioned reinforcers followed by food, while in the Control condition the conditioned reinforcer stimulus was always the same. After acquiring the discrimination, all the subjects were exposed to the extinction phase.
Results: The subjects of the Experimental condition needed about half of the sessions that the subjects of the Control condition needed to acquire the discrimination. In addition, subjects of the Experimental condition continued responding for more sessions than Control subjects in the extinction phase, although there were no differences in the resistance to extinction.
Conclusions: Acquisition speed is greater when a variety of conditioned reinforcers is applied.