Author: Joshua McGreen
McGreen, Joshua, 2024 The roles of cognitive biases, cravings, and inhibitory control in unhealthy beverage and food consumption, Flinders University, College of Education, Psychology and Social Work
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Excessive consumption of sugar-based soft drinks and unhealthy foods high in sugar, fat, and salt, has been recognized as a major public health concern and a significant factor contributing to the increasing prevalence of obesity globally. Current strategies to reduce soft drink consumption include soft drink taxation and promoting sugar-free alternatives. For unhealthy foods, public health initiatives have focused on their removal from environments such as schools, universities, and hospitals, as well as curbing the marketing of unhealthy foods, especially to children. However, these strategies have not been altogether successful. Notably, none of these strategies address the underlying mechanisms driving soft drink and unhealthy food consumption. Therefore, there is a need to explore alternative interventions that target such mechanisms, which may be more effective methods for reducing such consumption. Thus, the overarching aim of this thesis was to investigate the underlying mechanisms associated with soft drink and unhealthy food consumption and to assess the effectiveness of interventions targeting these mechanisms in reducing such consumption. Craving, the strong desire to consume a specific substance like drugs, alcohol, or food, was explored as one such mechanism. Furthermore, as dual-process models propose that behaviours are impacted by a combination of automatic (fast and unconscious) and controlled (slow and conscious) processes, cognitive biases and inhibitory (or self-regulatory) control were examined as potential predictors of appetitive consumption. Cognitive biases (automatic processing) refer to automatic inclinations that lead individuals to deviate from rational or objective thinking, whereas inhibitory control (controlled processing) refers to the ability to regulate behaviour or restrain impulsive actions. These mechanisms were the focus of investigation across a series of five studies.
Study 1 (Chapter 2), a cross-sectional study, investigated the roles of cognitive biases (evaluative, attentional, and approach biases) and inhibitory control in soft drink consumption. The results showed that evaluative bias, the automatic positive judgement of soft drinks, was the only cognitive bias associated with soft drink consumption. Lower inhibitory control was also associated with greater consumption, but only for men. Overall, Study 1 demonstrated that both automatic (evaluative bias) and controlled processes (inhibitory control) independently predict soft drink consumption.
Study 2 (Chapter 3), a second cross-sectional study, aimed to provide a thorough investigation of cravings for non-alcoholic beverages and their link to consumption. Participants reported cravings for a variety of non-alcoholic beverages, with coffee, soft drink, and water by far the most frequently craved. Unlike water cravings, which were primarily driven by thirst, coffee cravings were most often triggered by tiredness, while soft drink cravings were predominantly driven by external environmental cues. Across all beverages, as well as individually for soft drinks, stronger cravings were associated with a higher likelihood of drinking and consuming more of the craved beverage. In addition, the number of cravings for coffee and soft drink each uniquely predicted how much of these beverages was drunk over the course of a week.
Study 3 (Chapter 4), a meta-analysis, sought to determine whether inhibitory control, as measured by the Go/No-Go and Stop-Signal tasks, is associated with food consumption. Overall, there was a small association between inhibitory control and food choice or consumption. This association remained significant when inhibitory control was measured using the Stop-Signal Task. However, when measured with the Go/No-Go Task, this association was only significant in children and when food choice or consumption was measured objectively.
Study 4 (Chapter 5), a second meta-analysis, investigated how parameter differences in Go/No-Go and Stop-Signal inhibitory control interventions impact the effectiveness of such tasks in reducing food consumption. Overall, inhibitory control training was found to reduce food choices or consumption, but this effect was separately significant only for training protocols using the Go/No-Go Task. Among Go/No-Go protocols, a single training session led to greater reductions in food choices or consumption compared to multiple sessions. Furthermore, the effectiveness of Go/No-Go protocols in reducing food choices or consumption was found to be robust across various demographic groups.
Study 5 (Chapter 6), an experimental study, investigated the individual and combined effects of evaluative conditioning and Go/No-Go inhibitory control interventions in reducing soft drink choices and consumption. Neither intervention successfully altered its respective targeted mechanism (evaluative bias and motor responses to soft drink cues, respectively). Additionally, neither intervention, whether used alone or together, reduced soft drink choices or consumption. However, there was a trend (although not statistically significant) indicating that inhibitory control training may reduce soft drink choices among men. Thus, it was concluded that Go/No-Go inhibitory control training may be particularly effective for men in reducing soft drink choices or consumption.
Overall, the present thesis provides evidence for the relationships between underlying mechanisms and the consumption of soft drinks and unhealthy foods. Specifically, it identifies key targets for potentially reducing such consumption, namely evaluative bias towards soft drink cues, inhibitory control, and cravings for soft drinks. Thus, this thesis offers a valuable and unique contribution to understanding and potentially addressing a significant public health concern, namely soft drink and unhealthy food consumption.
Keywords: evaluative bias, evaluative conditioning, inhibitory control, devaluation, go/no-go task, stop-signal task, dual-process models, craving, soft drink consumption, soft drink choice, beverage consumption, food consumption, food choice
Subject: Psychology thesis
Thesis type: Doctor of Philosophy
Completed: 2024
School: College of Education, Psychology and Social Work
Supervisor: Eva Kemps