A pupillary index of susceptibility to decision biases

Eran Eldar*, Valkyrie Felso, Jonathan D. Cohen, Yael Niv

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Abstract: The demonstration that human decision-making can systematically violate the laws of rationality has had a wide impact on behavioural sciences. In this study, we use a pupillary index to adjudicate between two existing hypotheses about how irrational biases emerge: the hypothesis that biases result from fast, effortless processing and the hypothesis that biases result from more extensive integration. While effortless processing is associated with smaller pupillary responses, more extensive integration is associated with larger pupillary responses. Thus, we tested the relationship between pupil response and choice behaviour on six different foundational decision-making tasks that are classically used to demonstrate irrational biases. Participants demonstrated the expected systematic biases and their pupillary measurements satisfied pre-specified quality checks. Planned analyses returned inconclusive results, but exploratory examination of the data revealed an association between high pupillary responses and biased decisions. The findings provide preliminary support for the hypothesis that biases arise from gradual information integration. Protocol registration: The stage 1 protocol for this Registered Report was accepted in principle on 19 December 2018. The protocol, as accepted by the journal, can be found at https://doi.org/10.6084/m9.figshare.c.4368452.v1.

Original languageAmerican English
Pages (from-to)653-662
Number of pages10
JournalNature Human Behaviour
Issue number5
StatePublished - May 2021

Bibliographical note

Funding Information:
This project was made possible through grants from the Israel Science Foundation (grant No. 1094/20; to E.E.), Army Research Office (grant No. W911NF-14-1-0101; to Y.N.) and Templeton Foundation (to V.F., J.D.C. and Y.N.). The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.

Publisher Copyright:
© 2021, The Author(s), under exclusive licence to Springer Nature Limited.


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