Asymmetrical effects of posttraining outcome revaluation on outcome-selective Pavlovian-to-instrumental transfer of control in human adults

In outcome-selective Pavlovian-to-instrumental transfer (PIT), stimuli that are predictive of particular outcomes prime instrumental responses that are associated with these outcomes. Previous experiments with humans obtained evidence that a strong posttraining devaluation of the associated outcome abolishes outcome-selective PIT. The present study extends this research to an upvaluation of outcomes. Adults learned in a stock market paradigm to relate particular stimuli and responses with particular monetary outcomes. Participants preferred responses associated with the same outcome as that predicted by the Pavlovian cue in a first transfer test. Before a second test, one currency was devalued, while the value of another currency was increased. In two experiments, outcome devaluation reduced specific PIT, while the upvaluation had no effect. Thus, a downward shift in the reward value was more effective than an equidistant upward shift for a change of PIT.