Impaired Goal-Directed Planning in Transdiagnostic Compulsivity Is Explained by Uncertainty About Learned Task...

Diminished use of goal-directed (model-based) decision making is a hallmark of transdiagnostic compulsivity, promoting an overreliance on inflexible and habitual behaviors. However, the origin of this impairment remains unclear. Here, we tested the hypothesis that these impairments arise due to uncertainty within the internal world model that subserves goal-directed decision making.

We adapted a validated gamified decision-making task to characterize how individuals build an internal model of an environment, pairing these data with computational modeling to uncover the exact mechanisms underpinning behavior and quantify individual differences. Two samples of participants (a discovery sample and a preregistered replication sample, n = 551 and 1322, respectively) performed the task, and we also acquired longitudinal data over 2-week and 3-month periods to assess task reliability and stability of behavior over time.

In the discovery and replication samples, we found that individuals higher in compulsivity and intrusive thought learned more slowly and formed a less certain representation of the task's structure. This uncertainty mediated the link between compulsive symptoms and use of goal-directed behavior. Behavior in the task was relatively stable over a 3-month (n = 385) and 1-year (n = 326) period and did not predict changes in symptoms.

Our results suggest that reliance on habitual behaviors seen in individuals with high levels of compulsive symptoms result from a tendency to form less certain internal models of the external world. Given the stability of this behavior and its links to symptoms, this may represent a trait-level vulnerability for this symptom dimension.