Whole Reversal Versus Partial Reversal Advantage Effect on Same-Different Discriminations in Rats

Abstract

The present experiment has examined a whole reversal versus partial reversal advantage effect on same-different discrimination using a whole-partial reversal procedure in rats. This experiment was a limited parameter study of the reinforcer density variable from Phase 1 training to Phase 2 reversal. Rats were trained to criterion on 12 same-different tasks (6 same and 6 different tasks) and then given reversal training on either a whole reversal condition (W), in which all of the 12 tasks were reversed, a partial reversal-10-condition (P-10), in which 5 same and 5 different tasks were reversed, a partial reversal-6-condition (P-6), in which 3 same and 3 different tasks were reversed, or a partial reversal-2-condition (P-2), in which one same and one different task were reversed. Group W reversed faster than the other three partial groups. Group P-2 reversed faster than Group P-6, which in turn reversed faster than Group P-10. These results provided evidence that rats formed functional stimulus classes during initial same-different discrimination training.