Use of Number by Fish
2009

Fish Can Use Numbers

Sample size: 14 publication 10 minutes Evidence: high

Author Information

Author(s): Christian Agrillo, Marco Dadda, Giovanna Serena, Angelo Bisazza

Primary Institution: Department of General Psychology, University of Padova, Padova, Italy

Hypothesis

Can mosquitofish learn to discriminate between two and three objects without relying on non-numerical information?

Conclusion

Mosquitofish can learn to discriminate small quantities, even when non-numerical indicators of quantity are unavailable.

Supporting Evidence

  • Fish were able to discriminate between two and three objects even when non-numerical cues were controlled.
  • The study provides the first evidence that fish can use numbers similarly to primates.
  • Fish did not make more errors when non-numerical information was excluded.

Takeaway

Mosquitofish can tell the difference between two and three things, even when they can't see other clues like size or brightness.

Methodology

The study involved training mosquitofish to discriminate between two and three objects while controlling for non-numerical variables.

Limitations

The study only tested discrimination between two specific quantities (2 vs 3).

Participant Demographics

Ten female mosquitofish were used in the first experiment, and fourteen in the second.

Statistical Information

P-Value

p<0.001

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1371/journal.pone.0004786

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