Physical Activity Is Positively Associated with Model-Based Decision Making in Pursuit of Reward in Trauma-Exposed Adults.

Purpose: Sequential decision-making often involves a combination of simple trial-and-error learning (i.e., model-free learning), and more sophisticated learning where an abstract representation of the environment is formed, thereby facilitating prospective predictions about likely outcomes based on different choices (i.e., model-based learning). As such, the utilization of a model-based approach is thought to be advantageous in many contexts as it provides a more informed cognitive map. Emerging research suggests that trauma exposure may have a detrimental effect on model-based learning, which suggests that there may be clinical utility in examining pharmacological and/or behavioral approaches that boost model-based behavior. Although greater habitual physical activity (PA) is associated with enhanced cognitive function, no prior studies have examined the specific domain of model-based decision-making. This study aimed to examine whether greater PA is associated with greater model-based decision-making in pursuit of reward among trauma-exposed adults (N = 84).

Methods: Participants (62% women, 55% white, M ± SD age = 28 ± 9 y) completed the International Physical Activity Questionnaire-Short Form and a two-stage Markov task capable of quantifying model-free vs model-based decision-making. Mixed-effects logistic regression models were used to determine if PA volume (quartiles of MET-min/wk) promotes greater engagement in model-based behavioral strategies during the task.

Results: Participants from quartile 2 (β = 0.17, 95%CI = 0.11-0.23), quartile 3 (β = 0.27, 95%CI = 0.21-0.33), and quartile 4 (β = 0.23, 95%CI = 0.17-0.30) exhibited greater model-based decision-making compared to participants from quartile1 (β = 0.08, 95%CI = 0.02-0.14), with participants from quartile 3 exhibiting greater model-based decision-making compared to quartile 2.

Conclusions: PA volume is positively associated with a greater propensity to utilize model-based behavioral strategies during decision-making in pursuit of reward in trauma-exposed adults. Future research is needed to examine whether changes in PA behavior predict subsequent changes in model-based behavior.