Shahar, N;
Moran, R;
Hauser, TU;
Kievit, RA;
McNamee, D;
Moutoussis, M;
NSPN Consortium, .;
(2019)
Credit assignment to state-independent task representations and its relationship with model-based decision making.
Proceedings of the National Academy of Sciences
10.1073/pnas.1821647116.
(In press).
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Abstract
Model-free learning enables an agent to make better decisions based on prior experience while representing only minimal knowledge about an environment’s structure. It is generally assumed that model-free state representations are based on outcome-relevant features of the environment. Here, we challenge this assumption by providing evidence that a putative model-free system assigns credit to task representations that are irrelevant to an outcome. We examined data from 769 individuals performing a well-described 2-step reward decision task where stimulus identity but not spatial-motor aspects of the task predicted reward. We show that participants assigned value to spatial-motor representations despite it being outcome irrelevant. Strikingly, spatial-motor value associations affected behavior across all outcome-relevant features and stages of the task, consistent with credit assignment to low-level state-independent task representations. Individual difference analyses suggested that the impact of spatial-motor value formation was attenuated for individuals who showed greater deployment of goal-directed (model-based) strategies. Our findings highlight a need for a reconsideration of how model-free representations are formed and regulated according to the structure of the environment.
| Type: | Article |
|---|---|
| Title: | Credit assignment to state-independent task representations and its relationship with model-based decision making |
| Location: | United States |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1073/pnas.1821647116 |
| Publisher version: | https://doi.org/10.1073/pnas.1821647116 |
| Language: | English |
| Additional information: | © 2019 the Author(s). Published by PNAS. This open access article is distributed under Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/). |
| Keywords: | decision making, motor learning, reinforcement learning |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology > Imaging Neuroscience |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10078943 |
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