Uncertainty alters the balance between incremental learning and episodic memory
Abstract
A key question in decision making is how humans arbitrate between competing learning and memory systems to maximize reward. We address this question by probing the balance between the effects, on choice, of incremental trial-and-error learning versus episodic memories of individual events. Although a rich literature has studied incremental learning in isolation, the role of episodic memory in decision making has only recently drawn focus, and little research disentangles their separate contributions. We hypothesized that the brain arbitrates rationally between these two systems, relying on each in circumstances to which it is most suited, as indicated by uncertainty. We tested this hypothesis by directly contrasting contributions of episodic and incremental influence to decisions, while manipulating the relative uncertainty of incremental learning using a well-established manipulation of reward volatility. Across two large, independent samples of young adults, participants traded these influences off rationally, depending more on episodic information when incremental summaries were more uncertain. These results support the proposal that the brain optimizes the balance between different forms of learning and memory according to their relative uncertainties and elucidate the circumstances under which episodic memory informs decisions.
Data availability
All code, data, and software needed to reproduce the manuscript can be found here: https://codeocean.com/capsule/2024716/tree/v1; DOI: https://doi.org/10.24433/CO.1266819.v1
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Uncertainty alters the balance between incremental learning and episodic memoryCode Ocean, https://doi.org/10.24433/CO.1266819.v1.
Article and author information
Author details
Funding
National Science Foundation (1644869)
- Jonathan Nicholas
National Science Foundation (1822619)
- Nathaniel D Daw
National Science Foundation (1822619)
- Daphna Shohamy
National Institutes of Health (MH121093)
- Nathaniel D Daw
National Institutes of Health (MH121093)
- Daphna Shohamy
John Templeton Foundation (60844)
- Daphna Shohamy
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Human subjects: Informed consent was obtained online with approval from the Columbia University Institutional Review Board (IRB #1488)
Copyright
© 2022, Nicholas 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.
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