Balance between breadth and depth in human many-alternative decisions
Many everyday life decisions require allocating finite resources, such as attention or time, to examine multiple available options, like choosing an online food supplier. In these cases, our search resources can be spread across many options (breadth) or focused on a few of them (depth). Whilst theoretical work has described how finite resources should be allocated to maximise utility in these problems, evidence about how humans balance breadth and depth is lacking. We introduce a novel experimental paradigm where humans make a many-alternative decision under finite resources. In an imaginary scenario, participants allocate a finite budget to sample amongst multiple apricot suppliers in order to estimate the quality of their fruits, and ultimately choose the best one. We found that at low budget capacity participants sample as many suppliers as possible, and thus prefer breadth, whereas at high capacities participants sample just a few chosen alternatives in depth, and intentionally ignore the rest. The number of alternatives sampled increases with capacity following a power law with an exponent close to 0.75. In richer environments, where good outcomes are more likely, humans further favour depth. Participants deviate from optimality and tend to allocate capacity amongst the selected alternatives more homogeneously than it would be optimal, but the impact on the outcome is small. Overall, our results undercover a rich phenomenology of close-to-optimal behaviour and biases in complex choices.
The data and analysis scripts have been deposited in an OSF repository available herehttps://osf.io/kdbqs/?view_only=386d3bde49394e6bb88d247adc52b9ad
Article and author information
Howard Hughes Medical Institute (55008742)
- Ruben Moreno Bote
Institució Catalana de Recerca i Estudis Avançats (2016)
- Ruben Moreno Bote
Ministerio de Ciencia e Innovación (PID2019-108531GB-I00 AEI/FEDER)
- Salvador Soto-Faraco
European Regional Development Fund (Operative Programme for Catalunya 2014-2020)
- Salvador Soto-Faraco
Agència de Gestió d'Ajuts Universitaris i de Recerca (2019FI_B 00302)
- Alice Vidal
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Human subjects: Before starting the experiment, participants had to give their informed consent. This study was part of the project 'IMC: INTEGRACIÓN MULTISENSORIAL Y CONFLICTO' (PID2019-108531GB-I00) for which an ethical approval was obtained.
- Valentin Wyart, École normale supérieure, PSL University, INSERM, France
- Preprint posted: November 10, 2021 (view preprint)
- Received: January 11, 2022
- Accepted: September 12, 2022
- Accepted Manuscript published: September 15, 2022 (version 1)
- Version of Record published: October 17, 2022 (version 2)
© 2022, Vidal 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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