Uncertainty alters the balance between incremental learning and episodic memory
- Columbia University, United States
- Princeton University, United States
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.
Reviewing Editor
- Michael J Frank, Brown University, United States
Ethics
Human subjects: Informed consent was obtained online with approval from the Columbia University Institutional Review Board (IRB #1488)
Version history
- Preprint posted: July 6, 2022 (view preprint)
- Received: July 7, 2022
- Accepted: December 1, 2022
- Accepted Manuscript published: December 2, 2022 (version 1)
- Version of Record published: January 3, 2023 (version 2)
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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Uncertainty alters the balance between incremental learning and episodic memory
eLife 11:e81679.
https://doi.org/10.7554/eLife.81679
Further reading
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Asymmetries in the size of structures deep below the cortex explain how alpha oscillations in the brain respond to shifts in attention.
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Evidence suggests that subcortical structures play a role in high-level cognitive functions such as the allocation of spatial attention. While there is abundant evidence in humans for posterior alpha band oscillations being modulated by spatial attention, little is known about how subcortical regions contribute to these oscillatory modulations, particularly under varying conditions of cognitive challenge. In this study, we combined MEG and structural MRI data to investigate the role of subcortical structures in controlling the allocation of attentional resources by employing a cued spatial attention paradigm with varying levels of perceptual load. We asked whether hemispheric lateralization of volumetric measures of the thalamus and basal ganglia predicted the hemispheric modulation of alpha-band power. Lateral asymmetry of the globus pallidus, caudate nucleus, and thalamus predicted attention-related modulations of posterior alpha oscillations. When the perceptual load was applied to the target and the distractor was salient caudate nucleus asymmetry predicted alpha-band modulations. Globus pallidus was predictive of alpha-band modulations when either the target had a high load, or the distractor was salient, but not both. Finally, the asymmetry of the thalamus predicted alpha band modulation when neither component of the task was perceptually demanding. In addition to delivering new insight into the subcortical circuity controlling alpha oscillations with spatial attention, our finding might also have clinical applications. We provide a framework that could be followed for detecting how structural changes in subcortical regions that are associated with neurological disorders can be reflected in the modulation of oscillatory brain activity.
