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Frontiers in veterinary science2021; 8; 676888; doi: 10.3389/fvets.2021.676888

Using the Judgment Bias Task to Identify Behavioral Indicators of Affective State: Do Eye Wrinkles in Horses Reflect Mood?

Abstract: Identifying and validating behavioral indicators of mood are important for the assessment of animal welfare. Here, we investigated whether horses' eye wrinkle expression in a presumably neutral situation is a measure of mood as assessed in a cognitive judgment bias task (JBT). To this end, we scored pictures of the left and right eyes of 16 stallions for different aspects of eye wrinkle expression and tested the same individuals on a spatial JBT with active trial initiation. Eye wrinkle expressions were assessed by a qualitative assessment, i.e., the overall assessment of how "worried" horses look, the number of wrinkles, and the angle measured at the intersection of lines drawn through the eyeball and the topmost wrinkle. Correlations between the three eye wrinkle measures and the optimism index as a measure of horses' decisions in the JBT were not statistically significant, but with increasing optimism index, horses tended to be scored as looking less worried (qualitative assessment). We discuss our findings from different perspectives and make suggestions for future research, e.g., by calling for experimental induction of mood and thus greater variation within and/or between individuals and by investigating the interplay between shorter-lasting emotional and longer-lasting mood states to further explore the potential use of the JBT to validate eye wrinkles and other facial or body expressions as indicators of mood.
Copyright © 2021 Hintze and Schanz.
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Publication Date: 2021-07-08 PubMed ID: 34307525PubMed Central: PMC8295722DOI: 10.3389/fvets.2021.676888Google 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 article focuses on whether horses’ eye wrinkles expression in a neutral condition can serve as an indicator of its mood, as evaluated through a cognitive judgement bias task (JBT). The authors found that while there was no significant correlation between the two, horses with a higher optimism index tended to look less worried.

Experimental Process

  • The experiment involved the analysis of photos of left and right eyes of 16 stallions, assessing various aspects of eye wrinkle expression.
  • This process was followed up with cognitive judgement bias tasks (JBTs) involving the same horses.
  • The eye wrinkle expressions were evaluated based on a qualitative measure of how “worried” the horses appeared, the number of wrinkles, and the angular values at the intersection of lines passing through the eyeball and the uppermost wrinkle.
  • The link between the three measurements of eye wrinkle expressions and the optimism index was examined. The optimism index was used as a measure of horses’ behaviours in the JBT.

Results

  • Statistical analysis revealed no significant correlations between the three eye wrinkle measures and the optimism index.
  • However, the results reveal a tendency for horses with an increasing optimism index to be scored as looking less “worried”.

Suggestions for Future Research

  • Authors discussed the results from various perspectives and have proposed suggestions for future investigations.
  • One key recommendation is to experimentally induce mood variations, which would increase variations within and/or among individual horses.
  • The authors also suggest investigating the relationship between transient emotional states and longer-lasting mood states. The aim of this would be to better understand the potential use of the JBT as a validation tool for facial indicators of mood, such as eye wrinkles.

Cite This Article

APA
Hintze S, Schanz L. (2021). Using the Judgment Bias Task to Identify Behavioral Indicators of Affective State: Do Eye Wrinkles in Horses Reflect Mood? Front Vet Sci, 8, 676888. https://doi.org/10.3389/fvets.2021.676888

Publication

Frontiers in veterinary science
ISSN: 2297-1769
NlmUniqueID: 101666658
Country: Switzerland
Language: English
Volume: 8
Pages: 676888
PII: 676888

Researcher Affiliations

Hintze, Sara
  • Division of Livestock Sciences, Department of Sustainable Agricultural Systems, University of Natural Resources and Life Sciences, Vienna, Austria.
Schanz, Lisa
  • Division of Livestock Sciences, Department of Sustainable Agricultural Systems, University of Natural Resources and Life Sciences, Vienna, Austria.

Conflict of Interest Statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer MS declared a past co-authorship with one of the authors SH to the handling editor.

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Citations

This article has been cited 4 times.
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