Decoupling sensory from decisional choice biases in perceptual decision making

  1. Daniel Linares  Is a corresponding author
  2. David Aguilar-Lleyda
  3. Joan López-Moliner
  1. Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Spain
  2. Université Paris 1 Panthéon-Sorbonne, France
  3. Universitat de Barcelona, Spain


The contribution of sensory and decisional processes to perceptual decision making is still unclear, even in simple perceptual tasks. When decision makers need to select an action from a set of balanced alternatives, any tendency to choose one alternative more often—choice bias—is consistent with a bias in the sensory evidence, but also with a preference to select that alternative independently of the sensory evidence. To decouple sensory from decisional biases, here we asked humans to perform a simple perceptual discrimination task with two symmetric alternatives under two different task instructions. The instructions varied the response mapping between perception and the category of the alternatives. We found that from 32 participants, 30 exhibited sensory biases and 15 decisional biases. The decisional biases were consistent with a criterion change in a simple signal detection theory model. Perceptual decision making, thus, even in simple scenarios, is affected by sensory and decisional choice biases.

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The data and the code to do the statistical analysis and create the figures is available at

The following data sets were generated

Article and author information

Author details

  1. Daniel Linares

    Theoretical Neurobiology of Cortical Circuits, Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
    For correspondence
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-7473-4184
  2. David Aguilar-Lleyda

    Centre d'Économie de la Sorbonne, Université Paris 1 Panthéon-Sorbonne, Paris, France
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-6963-4069
  3. Joan López-Moliner

    Department of Cognition, Development and Psychology of Education, Universitat de Barcelona, Barcelona, Spain
    Competing interests
    The authors declare that no competing interests exist.


Departament de Salut of the Generalitat de Catalunya (SLT002/16/00338)

  • Daniel Linares

Catalan Government (2017SGR-48)

  • Joan López-Moliner

Fudación Alicia Koplowitz

  • Daniel Linares

Project AEI/Feder, UE (PSI2017-83493R)

  • Joan López-Moliner

Departament de Salut of the Generalitat de Catalunya (SLT006/17/00362)

  • Daniel Linares

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.


Human subjects: The study was approved by the ethical committee of the University of Barcelona (IRB00003099) and followed the requirements of the Helsinki convention. The participants, who did not know the hypothesis of the experiments, provided written consent to perform the experiments.

Reviewing Editor

  1. Maik C Stüttgen, University Medical Center Mainz, Germany

Publication history

  1. Received: November 28, 2018
  2. Accepted: March 23, 2019
  3. Accepted Manuscript published: March 27, 2019 (version 1)
  4. Version of Record published: April 11, 2019 (version 2)


© 2019, Linares 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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  1. Daniel Linares
  2. David Aguilar-Lleyda
  3. Joan López-Moliner
Decoupling sensory from decisional choice biases in perceptual decision making
eLife 8:e43994.

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