Study
Animals remember previous facial expressions that specific humans have exhibited
Proops, Leanne; Grounds, Kate; Smith, Amy Victoria; McComb, Karen
Current Biology, 2018
Horses were shown a photograph of a person wearing either an angry or a happy expression. Hours later, that same person — now with a neutral expression, and unaware which photograph the horse had seen — was presented to the animal, and its behaviour towards them was recorded.
- Studied in
- Equus caballus
- Sample size
- 24 domestic horses
Horses showed more left-eye gaze bias, associated with perceiving threat, and greater wariness towards people whose angry photograph they had previously seen, several hours after the exposure.
What it means
The authors' reading, and ours. Where they differ, that difference is the point.
How the authors put it
Horses form lasting memories linking a specific person’s identity to an emotional expression they previously displayed.
How NatureHQ reads it
The blinding matters here: the person meeting the horse did not know which photograph it had seen, which rules out the obvious route by which such a result could be produced accidentally. The claim is narrower than "horses read emotions" — it is that a remembered facial expression attaches to a remembered individual, which is a statement about memory and identity as much as about emotion.
- Modest sample of domestic horses accustomed to people.
- Left-gaze bias is an indirect measure whose interpretation is debated.
- Does not establish what the horse understands an angry expression to mean.
What this study is used for on NatureHQ
One study can inform several subjects. Here is everywhere this one is cited.
Published by: Cell PressPublished in a Cell Press journal.
doi.org/10.1016/j.cub.2018.03.035
This reference was resolved automatically against Crossref and OpenAlex on 2026-08-11.
NatureHQ summarises research in its own words and does not reproduce published text. Reviewed 2026-08-09.