Single-response appetitive Pavlovian to instrumental transfer is suppressed by aversive counter-conditioning

Environmental stimuli, when paired with reward, can influence behaviour in maladaptive ways, for example, by encouraging overeating or addiction. Such behaviour can be sensitive to reward value manipulations, under circumscribed conditions, but whether reward-seeking is also sensitive to stimulus value manipulations remains unclear. Thus, the current experiment investigated whether reducing the hedonic value of a reward-paired stimulus would reduce reward-seeking behaviour. In total, 36 participants successfully completed a single-response Pavlovian-instrumental transfer (PIT) task with a counter-conditioning procedure. The Pavlovian phase associated three conditioned stimuli (CSs) with money at 100%, 50%, or 0% contingency. Counter-conditioning then followed for the experimental group, who saw the 100% CS paired with unpleasant pictures, while the control group saw only neutral images. Instrumental training required participants to learn a button-pressing response to win money. The transfer phase contrasted instrumental responding during baseline and CS presentation. Both experimental and control groups liked the 100% CS more than the other CSs after Pavlovian training, but counter-conditioning reduced this 100% CS liking. In transfer, the experimental group showed an abolition of appetitive PIT, while the control group showed maintenance of appetitive PIT. However, this group difference was only evident in response vigour, not response initiation. In summary, CS hedonic value influences cue-potentiated instrumental responding. More specifically, hedonic value of a reward-paired cue influences the vigour of instrumental responses, but not the decision to initiate a response. These data may have relevance to smoking cessation policies, where the introduction of health warnings may be viewed as a real-world example of counter conditioning.