Paradoxical preference for more frequently occurring negative stimuli and for less frequently occurring positive stimuli as a function of amount of training in simultaneous discrimination learning

Development of a preference for more frequently occurring negative stimuli was found in a within-subject design. In this experiment, pigeons learned two simultaneous problems with an unequal number of training trials. At various stages in training, for example, the more-trained negative stimulus was paired with the less-trained negative stimulus for a single preference trial. These probe trials pointed to a swing in stimulus function in negative stimuli which also occurred at an earlier stage in positive (reward-correlated) stimuli. The paradoxical preference for less-trained positive over more-trained positive stimuli was found in this study, confirming the earlier reported phenomenon. The paradoxical preference for more-trained negative stimuli was discussed in terms of a frustration analysis. A symmetrical, albeit positive, emotional factor was discussed with regard to the paradoxical findings with positive probe trials.