Interspecific two-dimensional visual discrimination of faces in horses (Equus caballus).
Authors: Ragonese Giulia, Baragli Paolo, Mariti Chiara, Gazzano Angelo, Lanatà Antonio, Ferlazzo Adriana, Fazio Esterina, Cravana Cristina
Journal: PloS one
Summary
# Editorial Summary: Visual Face Discrimination in Horses Horses possess the cognitive ability to distinguish between two-dimensional images of equine faces and those of other domestic species (cattle, sheep, donkeys and pigs), a capacity that aligns with documented visual discrimination skills in other ungulates. Researchers trained ten horses using instrumental conditioning, presenting facial images as visual cues with food rewards, and measured their performance in both discrimination and reversal learning tasks; eight of the ten horses successfully differentiated between horse and non-horse faces, with comparable success in the reversal phase. Notably, horses demonstrated this discriminatory ability regardless of which specific images they were trained on, suggesting they recognise broader categorical differences rather than memorising individual features. The practical implications for equine professionals centre on understanding that horses process visual information about conspecifics and other animals at a categorical level, which may inform handling strategies, social housing decisions, and stable design—though the researchers appropriately raise questions about whether flat, two-dimensional imagery fully captures how horses process real-world animal recognition. This finding warrants further investigation into three-dimensional visual discrimination and natural behavioural contexts, as current results may underestimate the sophistication of equine visual cognition in practical settings.
Read the full abstract on PubMed
Practical Takeaways
- •Horses can visually distinguish conspecifics from other domestic species, supporting their natural ability to recognize herd members during mixed-species grazing or handling situations
- •This cognitive ability may explain how horses adjust their behaviour and communication when in proximity to different species on farms or in mixed pastures
- •Two-dimensional images may not fully represent real-world visual recognition; behaviour testing should consider whether 2D stimuli adequately reflect how horses process faces in practical settings
Key Findings
- •8 out of 10 horses successfully discriminated between 2D images of horse faces and faces of other species (cattle, sheep, donkeys, pigs)
- •Horses demonstrated comparable discrimination learning ability to other ungulates tested in similar paradigms
- •Horses successfully completed reversal learning tasks at similar performance levels
- •Horses did not differentiate between individual faces within each species category despite overall interspecific discrimination success