Abstract

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.

Data availability

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

The following data sets were generated

Article and author information

Author details

  1. Davide Potrich

    Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy
    For correspondence
    davide.potrich@unitn.it
    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
    giorgio.vallortigara@unitn.it
    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

Funding

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.

Reviewing Editor

  1. Andreas Nieder, University of Tübingen, Germany

Ethics

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).

Version history

  1. Received: September 20, 2021
  2. Preprint posted: October 5, 2021 (view preprint)
  3. Accepted: January 7, 2022
  4. Accepted Manuscript published: January 10, 2022 (version 1)
  5. Version of Record published: January 24, 2022 (version 2)

Copyright

© 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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  1. Davide Potrich
  2. Mirko Zanon
  3. Giorgio Vallortigara
(2022)
Archerfish number discrimination
eLife 11:e74057.
https://doi.org/10.7554/eLife.74057

Share this article

https://doi.org/10.7554/eLife.74057

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