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Home / Equine Research Bank / PLoS One / Interspecific two-dimensional visual discrimination of faces...
PloS one2021; 16(2); e0247310; doi: 10.1371/journal.pone.0247310

Interspecific two-dimensional visual discrimination of faces in horses (Equus caballus).

Abstract: In social animals, recognizing conspecifics and distinguishing them from other animal species is certainly important. We hypothesize, as demonstrated in other species of ungulates, that horses are able to discriminate between the faces of conspecifics and the faces of other domestic species (cattle, sheep, donkeys and pigs). Our hypothesis was tested by studying inter-and intra-specific visual discrimination abilities in horses through a two-way instrumental conditioning task (discrimination and reversal learning), using two-dimensional images of faces as discriminative stimuli and food as a positive reward. Our results indicate that 8 out of 10 horses were able to distinguish between two-dimensional images of the faces of horses and images showing the faces of other species. A similar performance was obtained in the reversal task. The horses' ability to learn by discrimination is therefore comparable to other ungulates. Horses also showed the ability to learn a reversal task. However, these results were obtained regardless of the images the tested horses were exposed to. We therefore conclude that horses can discriminate between two dimensional images of conspecifics and two dimensional images of different species, however in our study, they were not able to make further subcategories within each of the two categories. Despite the fact that two dimensional images of animals could be treated differently from two dimensional images of non-social stimuli, our results beg the question as to whether a two-dimensional image can replace the real animal in cognitive tests.
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Publication Date: 2021-02-19 PubMed ID: 33606816PubMed Central: PMC7894942DOI: 10.1371/journal.pone.0247310Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research study explores the ability of horses to visually distinguish between 2-dimensional images of horse faces and those of other domestic animal species. The study found that most horses could identify the difference, even when the images were reversed, but they struggled to categorize the images any further.

Objective of the Research

  • The main objective of this research was to investigate the ability of horses to visually distinguish between faces of their own species (conspecifics) and those of other domestic animal species, using two-dimensional images.

Research Methodology

  • The researchers used a two-way instrumental conditioning task to test the distinction and reversal learning abilities of the horses. This task involved using two-dimensional images of faces as discriminative stimuli and food as a positive reward.
  • A total of 10 horses participated in the experiment. They were shown images of horse faces and those of other domestic species including cattle, sheep, donkeys and pigs.

Results and Findings

  • The study found that 8 out of the 10 horses were able to successfully distinguish between the 2D images of horse faces and those of other species.
  • The horses’ performance remained similar even when the task was reversed, indicating their ability to learn by discrimination is comparable to other ungulates.
  • Despite this, the horses were unable to make further subcategories within each of the two main categories (horse faces versus other animal faces). This pointed towards a limit in their visual discrimination ability.

Conclusions and Implications

  • The conclusion of this research was that while horses can visually discriminate between 2D images of their own species and other domestic animal species, their ability to categorize these images further is limited.
  • The researchers also questioned the validity of using two-dimensional images as replacements for real animals in cognitive tests. This opens up room for further research on the limitations of 2D images in animal cognition studies.

Cite This Article

APA
(2021). Interspecific two-dimensional visual discrimination of faces in horses (Equus caballus). PLoS One, 16(2), e0247310. https://doi.org/10.1371/journal.pone.0247310

Publication

PloS one
ISSN: 1932-6203
NlmUniqueID: 101285081
Country: United States
Language: English
Volume: 16
Issue: 2
Pages: e0247310
PII: e0247310

Researcher Affiliations

MeSH Terms

  • Animals
  • Animals, Domestic
  • Cattle
  • Discrimination Learning / physiology
  • Discrimination, Psychological
  • Female
  • Horses
  • Male
  • Pattern Recognition, Visual / physiology
  • Recognition, Psychology
  • Visual Perception / physiology

Conflict of Interest Statement

The authors have declared that no competing interests exist.

References

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Citations

This article has been cited 1 times.
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