1. Neuroscience
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Archerfish number discrimination

  1. Davide Potrich  Is a corresponding author
  2. Mirko Zanon
  3. Giorgio Vallortigara  Is a corresponding author
  1. University of Trento, Italy
Research Article
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Cite this article as: eLife 2022;11:e74057 doi: 10.7554/eLife.74057


Debates have arisen as to whether non-human animals actually can learn abstract non-symbolic numerousness or whether they always rely on some continuous physical aspect of the stimuli, covarying with number. Here we investigated archerfish (Toxotes jaculatrix) non-symbolic numerical discrimination with accurate control for co-varying continuous physical stimulus attributes. Archerfish were trained to select one of two groups of black dots (Exp. 1: 3 vs. 6 elements; Exp. 2: 2 vs. 3 elements); these were controlled for several combinations of physical variables (elements’ size, overall area, overall perimeter, density and sparsity), ensuring that only numerical information was available. Generalization tests with novel numerical comparisons (2 vs. 3, 5 vs. 8 and 6 vs. 9 in Exp. 1; 3 vs. 4, 3 vs. 6 in Exp. 2) revealed choice for the largest or smallest numerical group according to the relative number that was rewarded at training. None of the continuous physical variables, including spatial frequency, were affecting archerfish performance. Results provide evidence that archerfish spontaneously use abstract relative numerical information for both small and large numbers when only numerical cues are available.

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All data generated or analysed during this study have been deposited in Dryad.

The following data sets were generated

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Author details

  1. Davide Potrich

    Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy
    For correspondence
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-0928-628X
  2. Mirko Zanon

    Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-4062-1496
  3. Giorgio Vallortigara

    Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy
    For correspondence
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-8192-9062


H2020 European Research Council (833504)

  • Giorgio Vallortigara

Progetti di Rilevante Interesse Nazionale (2017PSRHPZ)

  • Giorgio Vallortigara

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


Animal experimentation: The present research was carried out at the Animal Cognition and Neuroscience Laboratory (ACN Lab) of the CIMeC (Center for Mind/Brain Sciences), at the University of Trento (Italy). All husbandry and experimental procedures complied with European Legislation for the Protection of Animals used for Scientific Purposes (Directive 2010/63/EU) and were approved by the Scientific Committee on Animal Health and Animal Welfare (Organismo Preposto al Benessere Animale, OPBA) of the University of Trento and by the Italian Ministry of Health (Protocol n. 932/2020-PR).

Reviewing Editor

  1. Andreas Nieder, University of Tübingen, Germany

Publication history

  1. Received: September 20, 2021
  2. Accepted: January 7, 2022
  3. Accepted Manuscript published: January 10, 2022 (version 1)


© 2022, Potrich 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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