In uncertain or unstable environments, sometimes the best decision is to change your mind. To shed light on this flexibility, we evaluated how the underlying decision policy adapts when the most rewarding action changes. Human participants performed a dynamic two-armed bandit task that manipulated the certainty in relative reward (conflict) and the reliability of action-outcomes (volatility). Continuous estimates of conflict and volatility contributed to shifts in exploratory states by changing both the rate of evidence accumulation (drift rate) and the amount of evidence needed to make a decision (boundary height), respectively. At the trialwise level, following a switch in the optimal choice, the drift rate plummets and the boundary height weakly spikes, leading to a slow exploratory state. We find that the drift rate drives most of this response, with an unreliable contribution of boundary height across experiments. Surprisingly, we find no evidence that pupillary responses associated with decision policy changes. We conclude that humans show a stereotypical shift in their decision policies in response to environmental changes.
Behavioral data and their computational derivatives are available at https://github.com/kmbond/dynamic_decision_policy_reconfiguration. Code used to generate figures can be found here: https://github.com/kmbond/dynamic_decision_policy_reconfiguration/tree/master/revised_figure_nbs.Raw pupillometry data (DOI: 10.1184/R1/13543133), the features of the task-evoked pupillometry response (DOI: 10.1184/R1/13543067), and the principal components calculated from those features (DOI: 10.1184/R1/13543160) are available at https://kilthub.cmu.edu/projects/Dynamic_decision_policy_reconfiguration_under_outcome_uncertainty/96116.
- Krista Bond
- Timothy Verstynen
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Human subjects: Neurologically healthy adults were recruited from thelocal university population. All procedures were approved by the Carnegie Mellon University Institutional Review Board (Approval Code: 2018_00000195; Funding: Air Force Research Laboratory, Grant Office ID: 180119). All research participants provided informed consent to participate in the study and consent to publish any research findings based on their provided data.
- Redmond G O'Connell, Trinity College Dublin, Ireland
- Received: December 7, 2020
- Accepted: December 23, 2021
- Accepted Manuscript published: December 24, 2021 (version 1)
© 2021, Bond et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.