Weapons of mass consumption: The psychological mechanisms driving over indulgence

Excess-consumption in the general population, whether economic, dietary, or substance-oriented, presents numerous health and social challenges. Psychoactive substances, energy dense food, and certain media and retail products tend to provide immediate and exaggerated reinforcement, in turn promoting excessive consumption that contributes to individual and societal harms. These stimuli may be understood to be ‘supernormal’ in that they activate reward pathways and approach behaviour more so than naturally occurring stimuli for which these pathways were intended. This thesis investigated the issue of unhealthy excess consumption in the Australian general population, with a key focus to define, measure, and predict individual differences and preferences contributing to excessive consumption. These objectives were addressed through six studies involving a face to face interview study, a series of cross-sectional online surveys, and a reaction time task. Key findings were: 1) Shared variance amongst several types of rewarding stimuli; including fast food, salt, caffeine, television, gambling products, and illicit drugs; can be explained by an underlying individual difference factor; 2) People tend to systematically vary in their preference toward reward from artificial modern day consumer products (i.e., supernormal stimuli) over natural forms of reward, which I have termed “supernormal preference”; 3) Reward drive (RD) and rash impulsivity (RI) uniquely and differentially predict the above-average consumption of a variety of consumer products and activities as well as a preference towards supernormal over natural reward; and lastly, 4) supernormal preference, RD, and RI are positively related to the latent factor reflecting the consumption of several types of hedonic, modern day consumer products. These finding are discussed in terms of the neurological and evolutionary underpinnings of reinforcement processes and the impact that a preference for super normal reward, and/or a rash impulsive disposition, might have on individuals, health interventions, and future research.