Instrumental performance following saccharin pre-feeding

The effect of pre-feeding rats with a saccharin solution on instrumental performance, established with the same reinforcer, was studied in two experiments. Experiment 1 demonstrated that such pre-feeding depresses subsequent instrumental performance in an extinction test after training on a variable ratio schedule. In contrast, training on a variable interval schedule in Experiment 2 rendered instrumental performance impervious to pre-feeding. The motivational effects of pre-feeding with a non-nutritive substance appear to act through an incentive rather than drive process.