Motivational processes contributing to disturbances in women's body image and eating

Reinforcement Sensitivity Theory (RST) provides a neurobiological personality framework for understanding approach and avoidance behavioural patterns. Recent research suggests an association between RST personality traits (reward interest and behavioural inhibition system [BIS]) and women's body image and eating behaviours. The current study aimed to extend this research by testing for indirect relationships between reward interest and BIS and eating disorder symptoms, as mediated through thin ideal internalisation. Adult female participants (N = 354, M = 22.06 years of age, SD = 6.78) completed self-report measures of reward interest, BIS, thin ideal internalisation, and eating disorder symptoms (i.e., restraint, eating concerns, weight and shape concerns). Indirect relationships were tested using bootstrapped mediation analyses. Results showed thin ideal internalisation mediated the pathways between the BIS and restraint, eating concern, and weight and shape concerns. Reward interest was not associated with thin ideal internalisation, or with eating disorder symptoms. Although the application of RST to women's body image is an emerging research area, these novel findings suggest BIS trait sensitivity may increase women's risk of body image concerns and restricted eating, via increased levels of thin ideal internalisation. Overall, these findings provide preliminary support for inclusion of individual differences in BIS sensitivity in risk factor models of body image and eating disturbances. Future research should aim to replicate these findings in more diverse samples, using longitudinal designs.