Distinct computational mechanisms underlying cognitive flexibility deficits in impulsivity and compulsivity

Abstract Cognitive flexibility, the ability to quickly adapt to changing environmental demands, is a hallmark of human behaviour, and is impaired across multiple psychiatric disorders. Especially compulsivity and impulsivity disorders have been linked to impaired adaptive learning and flexibility. Initial computational investigations suggested these distinct psychiatric dimensions suffer from the same underlying neurocognitive impairments, related to stochasticity during choice. However, a recent advance in computational neuroscience has demonstrated that imprecision in the learning process itself can account for a large portion of behavioural variability traditionally attributed to choice-stochasticity. Here, in a series of large-scale experiments using both lab-designed and gamified citizen-science tasks, we show that distinct computational markers are affected in compulsivity and impulsivity. Whilst impulsivity is tied to an imprecision in learning across valence domains, (hygiene-related) compulsivity is linked to choice-stochasticity. This double-dissociation demonstrates that distinct neurocomputational mechanisms can drive seemingly similar behavioural deficits, only dissociable using targeted computational approaches.