The influence of dietary patterns on outcomes in a Bayesian choice task

Previous research has investigated the impact of diet on cognition, but the focus has often been on general cognition. This paper reports on a preregistered cross-sectional study aimed at testing for specific executive function differences across individuals who self-reported one of four distinct dietary patterns: No Diet, No Sugar, Vegetarian, or Mediterranean Diet pattern. Our hypotheses were aimed at testing whether adherence to a specialty diet improved decision making relative to those who reported following No Diet.

We administered an incentivized Bayesian choice task to all participants. The task involved multiple components of information-existing information (base rate odds) as well as new information (sample draw evidence)-to allow a test of how these information components were used in making probability assessments, and how this may differ by self-reported dietary pattern. Sample size, hypotheses, and analysis plans were all determined ex ante and registered on the Open Science Framework. Multi-variate linear and non-linear estimation methods were used to analyze the data.

Our data failed to support our pre-registered hypotheses. In fact, we found some evidence that self-reported adherence to a specialty No Sugar Diet was associated with a reduced decision accuracy and was connected to an increased imbalance in how the participant weighted the two available sources of information when making choices.

Our results suggest that decision making is nuanced among dietary groups, but that short-term incentivized decisions in an ecologically valid field setting are likely not improved solely by following promoted dietary patterns such as the Mediterranean or Vegetarian diets.