Luminance and chromatic discrimination in the horse (Equus caballus).
Abstract: Equine colour vision was measured under conditions that minimised the possibility of animals using brightness cues to make chromatic discriminations. In a two-stage study, we first obtained luminance discrimination functions for achromatic targets then tested for chromatic discrimination over a range of target luminances. Horses were trained on a two-choice discrimination task. The positive stimulus was varied in luminance and/or colour using neutral density and broad band colour filters. The negative stimulus appeared as a uniform grey. In the brightness discrimination task, the horses performed well at large luminance differences but their percentage of correct responses declined to near chance levels at differences of less than 0.2 log units. In addition, a decrement in performance was noted at luminance differences of less than 0.2 log units for green and yellow chromatic discrimination functions, suggesting that horses cannot easily discriminate yellow and green from grey. However, the chromatic discrimination functions for red and blue showed that animals performed very well across the full range of target luminances. These results suggest that horses are at least dichromats.
Publication Date: 1999-03-01 PubMed ID: 24897231DOI: 10.1016/s0376-6357(98)00039-4Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
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.
This research paper explores the ability of horses to distinguish different colours and brightness levels, with evidence suggesting horses are at least dichromats – capable of distinguishing two colors.
Methodology
- The study was carried out in two stages. First, the researchers obtained luminance discrimination functions using targets of varying brightness but without any color information. They then tested for chromatic discrimination across a range of target brightness.
- The horses were trained on a two-choice discrimination task. This involved presenting the horses with two stimuli, one positive and one negative.
- The positive stimulus varied in brightness and/or color, which was achieved by using neutral density and broad band color filters.
- The negative stimulus appeared as a uniform grey to the horses. The study then recording the horse’s responses to each stimulus.
Findings
- In the brightness discrimination task, the results showed that horses performed well at large brightness differences. However, their accuracy dropped considerably when the brightness difference was less than 0.2 log units.
- The study also observed deterioration in performance as the brightness differences reduced to less than 0.2 log units in green and yellow color discrimination tasks. This suggests that horses have difficulty distinguishing yellow and green from grey.
- Contrarily, the horses showed excellent performance across the entire range of target brightness in the red and blue color discrimination tasks. Therefore, horses seem to have better chromatic perception for red and blue than for green and yellow.
- The findings overall suggest that horses are at least dichromats. This means they are capable of distinguishing two chromatic (color) dimensions.
Implications
- This research could have practical implications for items designed for horses such as feeders, blankets, and other equipment. Designing these items in colors that horses can easily distinguish might enhance their usability for horses.
- Horse training methods could also benefit from considering horses’ color perception, potentially making training procedures more efficient.
Cite This Article
APA
Macuda T, Timney B.
(1999).
Luminance and chromatic discrimination in the horse (Equus caballus).
Behav Processes, 44(3), 301-307.
https://doi.org/10.1016/s0376-6357(98)00039-4 Publication
Researcher Affiliations
- Department of Psychology, University of Western Ontario, London, Ontario, Canada N6A 5C2.
Citations
This article has been cited 5 times.- Ragonese G, Baragli P, Mariti C, Gazzano A, Lanatà A, Ferlazzo A, Fazio E, Cravana C. Interspecific two-dimensional visual discrimination of faces in horses (Equus caballus).. PLoS One 2021;16(2):e0247310.
- Rørvang MV, Nielsen BL, McLean AN. Sensory Abilities of Horses and Their Importance for Equitation Science.. Front Vet Sci 2020;7:633.
- Paul SC, Stevens M. Horse vision and obstacle visibility in horseracing.. Appl Anim Behav Sci 2020 Jan;222:104882.
- Roth LS, Balkenius A, Kelber A. The absolute threshold of colour vision in the horse.. PLoS One 2008;3(11):e3711.
- Detto T. The fiddler crab Uca mjoebergi uses colour vision in mate choice.. Proc Biol Sci 2007 Nov 22;274(1627):2785-90.
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
