@article {4199, title = {Incentives Boost Model-Based Control Across a Range of Severity on Several Psychiatric Constructs}, journal = {Biological Psychiatry}, volume = {85}, year = {2019}, month = {03/2019}, pages = {425 - 433}, abstract = {

Background

Human decision making exhibits a mixture of model-based and model-free control. Recent evidence indicates that arbitration between these two modes of control ({\textquotedblleft}metacontrol{\textquotedblright}) is based on their relative costs and benefits. While model-based control may increase accuracy, it requires greater computational resources, so people invoke model-based control only when potential rewards exceed those of model-free control. We used a sequential decision task, while concurrently manipulating performance incentives, to ask if symptoms and traits of psychopathology decrease or increase model-based control in response to incentives.

Methods

We recruited a nonpatient population of 839 online participants using Amazon Mechanical Turk who completed transdiagnostic self-report measures encompassing symptoms, traits, and factors. We fit a dual-controller reinforcement learning model and obtained a computational measure of model-based control separately for small incentives and large incentives.

Results

None of the constructs were related to a failure of large incentives to boost model-based control. In fact, for the sensation seeking trait and anxious-depression factor, higher scores were associated with a larger incentive effect, whereby greater levels of these constructs were associated with larger increases in model-based control. Many constructs showed decreases in model-based control as a function of severity, but a social withdrawal factor was positively correlated; alcohol use and social anxiety were unrelated to model-based control.

Conclusions

Our results demonstrate that model-based control can reliably be improved independent of construct severity for most measures. This suggests that incentives may be a useful intervention for boosting model-based control across a range of symptom and trait severity.

}, keywords = {Computational psychiatry, Habits and goals Incentives, Model-based control, Psychiatric constructs, reinforcement learning}, issn = {00063223}, doi = {10.1016/j.biopsych.2018.06.018}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0006322318316329}, author = {Patzelt, Edward H. and Kool, Wouter and Millner, Alexander J. and Samuel J Gershman} } @article {4201, title = {The transdiagnostic structure of mental effort avoidance}, journal = {Scientific Reports}, volume = {9}, year = {2019}, month = {02/2019}, abstract = {

The law of least mental effort states that, everything else being equal, the brain tries to minimize mental effort expenditure during task performance by avoiding decisions that require greater cognitive demands. Prior studies have shown associations between disruptions in effort expenditure and specific psychiatric illnesses (e.g., schizophrenia and depression) or clinically-related symptoms and traits (e.g., anhedonia and apathy), yet no research has explored this issue transdiagnostically. Specifically, this research has largely focused on a single diagnostic category, symptom, or trait. However, abnormalities in effort expression could be related to several different psychiatrically-relevant constructs that cut across diagnostic boundaries. Therefore, we examined the relationship between avoidance of mental effort and a diverse set of clinically-related symptoms and traits, and transdiagnostic latent factors in a large sample (n = 811). Only lack of perseverance, a dimension of impulsiveness, was associated with increased avoidance of mental effort. In contrast, several constructs were associated with less mental effort avoidance, including positive urgency, distress intolerance, obsessive-compulsive symptoms, disordered eating, and a factor consisting of compulsive behavior and intrusive thoughts. These findings demonstrate that deviations from normative effort expenditure are associated with a number of constructs that are common to several forms of psychiatric illness.

}, doi = {10.1038/s41598-018-37802-1}, url = {http://www.nature.com/articles/s41598-018-37802-1}, author = {Patzelt, Edward H. and Kool, Wouter and Millner, Alexander J. and Samuel J Gershman} }