The influence of associative reward learning on motor inhibition.

Stimuli that predict a rewarding outcome can cause difficulties to inhibit unfavourable behaviour. Research suggests that this is also the case for stimuli with a history of reward extending these effects on action control to situations, where reward is no longer accessible. We expand this line of research by investigating if previously reward-predictive stimuli promote behavioural activation and impair motor inhibition in a second unrelated task. In two experiments participants were trained to associate colours with a monetary reward or neutral feedback. Afterwards participants performed a cued go/no-go task, where cues appeared in the colours previously associated with feedback during training. In both experiments training resulted in faster responses in rewarded trials providing evidence of a value-driven response bias as long as reward was accessible. However, stimuli with a history of reward did not interfere with goal-directed action and inhibition in a subsequent task after removal of the reward incentives. While the first experiment was not conclusive regarding an impact of reward-associated cues on response inhibition, the second experiment, validated by Bayesian statistics, clearly questioned an effect of reward history on inhibitory control. This stands in contrast to earlier findings suggesting that the effect of reward history on subsequent action control is not as consistent as previously assumed. Our results show that participants are able to overcome influences from Pavlovian learning in a simple inhibition task. We discuss our findings with respect to features of the experimental design which may help or complicate overcoming behavioural biases induced by reward history.