Human complex exploration strategies are enriched by noradrenaline-modulated heuristics
Abstract
An exploration-exploitation trade-off, the arbitration between sampling a lesser-known against a known rich option, is thought to be solved using computationally demanding exploration algorithms. Given known limitations in human cognitive resources, we hypothesised the presence of additional cheaper strategies. We examined for such heuristics in choice behaviour where we show this involves a value-free random exploration, that ignores all prior knowledge, and a novelty exploration that targets novel options alone. In a double-blind, placebo-controlled drug study, assessing contributions of dopamine (400mg amisulpride) and noradrenaline (40mg propranolol), we show that value-free random exploration is attenuated under the influence of propranolol, but not under amisulpride. Our findings demonstrate that humans deploy distinct computationally cheap exploration strategies and where value-free random exploration is under noradrenergic control.
Data availability
All necessary resources are publicly available at: https://github.com/MagDub.
Article and author information
Author details
Funding
Max-Planck-Gesellschaft
- Magda Dubois
Wellcome Sir Hendry Dale Fellowship (211155/Z/18/Z)
- Tobias U Hauser
Jacobs Foundation (2017-1261-04)
- Tobias U Hauser
Wellcome Trust Investigator Award (098362/Z/12/Z)
- Raymond J Dolan
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- Thorsten Kahnt, Northwestern University, United States
Ethics
Human subjects: The study was approved by the UCL research committee (REC No 6218/002) and all subjects provided written informed consent
Version history
- Received: June 12, 2020
- Accepted: January 3, 2021
- Accepted Manuscript published: January 4, 2021 (version 1)
- Version of Record published: January 19, 2021 (version 2)
Copyright
© 2021, Dubois 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.
Metrics
-
- 2,951
- views
-
- 358
- downloads
-
- 32
- citations
Views, downloads and citations are aggregated across all versions of this paper published by eLife.
Download links
Downloads (link to download the article as PDF)
Open citations (links to open the citations from this article in various online reference manager services)
Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)
Further reading
-
- Genetics and Genomics
- Neuroscience
Single-cell RNA sequencing reveals the extent to which marmosets carry genetically distinct cells from their siblings.
-
- Neuroscience
We are unresponsive during slow-wave sleep but continue monitoring external events for survival. Our brain wakens us when danger is imminent. If events are non-threatening, our brain might store them for later consideration to improve decision-making. To test this hypothesis, we examined whether novel vocabulary consisting of simultaneously played pseudowords and translation words are encoded/stored during sleep, and which neural-electrical events facilitate encoding/storage. An algorithm for brain-state-dependent stimulation selectively targeted word pairs to slow-wave peaks or troughs. Retrieval tests were given 12 and 36 hr later. These tests required decisions regarding the semantic category of previously sleep-played pseudowords. The sleep-played vocabulary influenced awake decision-making 36 hr later, if targeted to troughs. The words’ linguistic processing raised neural complexity. The words’ semantic-associative encoding was supported by increased theta power during the ensuing peak. Fast-spindle power ramped up during a second peak likely aiding consolidation. Hence, new vocabulary played during slow-wave sleep was stored and influenced decision-making days later.