The Influence of Reward Associations in the Facilitation and Impairment of Attention and Conflict Processing

Abstract

The ability to inhibit rewarding impulses to focus on goal-relevant information is a key feature of self-control and is implicated in many psychopathologies and maladaptive behaviours. Focusing on a feature such as the font colour of a word is impaired when the word meaning does not match the font colour (e.g., the word RED in a blue font colour), but even more so when the word meaning is associated with reward (i.e., a potential reward is available when the font colour of the word is red). This phenomenon is referred to as the modulation of interference by the reward association (MIRA) and is contrasted with the improvement of performance when the task-relevant font colour signals a potential reward (reward responsiveness). The present dissertation explores how reward influences Stroop performance, the psychometric properties of these influences, how individuals differ in the influence of reward on their attentional performance, and group-level experimental manipulations that modulate these effects. In study 1, individual differences in behavioural measures of reward processing from the rewarded Stroop task (i.e., MIRA and reward responsiveness) and self-report measures of reward sensitivity and self-control were examined. While individual differences in reward responsiveness were reliable, individual differences in MIRA were not, suggesting that only reward responsiveness should be used to measure individual differences in behaviour. None of the self-report measures were related to behavioural measures suggesting that self-report and behavioural measures of similar constructs cannot be used interchangeably. Finally, there was no indication that reward responsiveness and MIRA were related In study 2, I used group-level manipulations to examine factors that could modulate reward responsiveness and MIRA. Whereas MIRA was relatively unaffected by these manipulations, reward responsiveness was increased for a large versus small reward, especially when colour-outcome instructions were provided. Further, individuals with high reward responsive tendencies responded faster to obtain a large reward but only when they were previously told which colour signals the large reward. Overall, these results highlight the dissociation between how reward can facilitate and impair attentional performance, and that further understanding this dissociation can have implications for our understanding of motivation and undesired reward-driven distraction.