The effects of feature type in operant serial feature-positive discriminations

In two experiments, rats were trained on two operant serial feature positive discriminations in which one feature was a flavored solution and the second feature was a visual or auditory cue. As in a previous study (Goddard & Holland, 1996), transfer of a feature's control to the target of the other discrimination was not observed when the flavor feature and the reinforcer were flavored sucrose solutions (Experiment 1). The performance of comparison groups showed that this lack of transfer was not due to confounded differences in the event contingencies resulting from having similar stimuli serve as feature and reinforcer. By contrast, in Experiment 2, transfer was observed between visual and flavor features when the flavor feature was unsweetened and the reinforcer was plain sucrose. These results suggest that the lack of transfer in Experiment 1 and in Goddard and Holland's (1996) study were related to the biological significance or hedonic properties of the sucrose feature.