'Don't stop believing': The role of training beliefs in cognitive bias modification paradigms.

Cognitive Bias Modification (CBM) paradigms have previously been applied to target appetite (craving, hunger) and food intake, and are hypothesised to reduce unhealthy food consumption. However, inconsistencies in relation to training outcomes raise questions regarding the efficacy of CBM as a standalone intervention. Furthermore, individual level factors (such as belief in the intervention efficacy) may influence expectations of behaviour change following training. Across two pre-registered studies, our aim was to investigate how directly manipulating beliefs in relation to training purpose and effectiveness influenced food value and choice across two popular CBM paradigms (Inhibitory Control Training (ICT: Study 1) and Evaluative Conditioning (EC: Study 2)). In online studies, participants were presented with a paragraph describing the CBM technique positively (or an unrelated control message) prior to completing either active or control CBM training. Across both studies, the results revealed that active CBM training resulted in a reduction to unhealthy food value (relative to pre-training), but only when paired with a positive manipulation message. Participants who received a control message displayed no significant changes to food value, even where active CBM training was provided. These results suggest that participant beliefs and expectancies have important consequences for CBM effectiveness. Future research should further investigate these factors within CBM contexts to identify their role within successful behaviour change interventions.