Working memory capacity influences decision making for healthy and unhealthy foods
Carr, Katelyn A.
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Working memory is an important component of executive function processes that allows one to maintain and manipulate mental information, in addition to controlling attention and directing cognitive resources. Working memory is related to decision-making processes, especially for decisions between reinforcers that offer immediate versus delayed gratification. The goal of this dissertation is to examine how working memory capacity contributes to failures in decision making, in the context of healthy and unhealthy foods. This is an ideal choice scenario to study the role of working memory in a dual systems decision model, due to food being a motivating reinforcer and the ability to measure changes in motivation to obtain food within the context of food choices using a substitution paradigm borrowed from behavioral economics. In this dissertation, we provide evidence that working memory plays a role in the reinforcing efficacy of food by demonstrating a moderation effect of working memory and attentional bias to food on monetary choices for unhealthy foods (Study 1). We then extended this research to examine how manipulating working memory influences foods choices and substitution (Study 2 & 3). When decreasing working memory using a letter load, we found that individuals with low working memory capacity were more likely to substitute healthy for unhealthy foods, and this effect was moderated by the available working memory resource manipulation (Study 2). Finally, we attempted to increase working memory resources using an executive function training program, but were unable to improve working memory sufficiently (Study 3). The research presented here offers an initial step in how to study substitutability between foods, in addition to cognitive components in substitution decision making. Future research has a variety of directions that include components to strengthen substitution of healthy foods for clinical applications and studying the theoretical dual-systems model and its applications to food choice.