Uncertainty alters the balance between incremental learning and episodic memory

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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

The following data sets were generated

(2022) Uncertainty alters the balance between incremental learning and episodic memory
Code Ocean, https://doi.org/10.24433/CO.1266819.v1.

https://codeocean.com/capsule/2024716/tree/v1

Article and author information

Author details

Jonathan Nicholas

Columbia University, New York, United States

For correspondence
jonathan.nicholas@columbia.edu

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0002-2314-0765
Nathaniel D Daw

Department of Psychology, Princeton University, Princeton, United States

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0001-5029-1430
Daphna Shohamy

Columbia University, New York, United States

Competing interests
The authors declare that no competing interests exist.

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

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.