ArticleScientific reports2022
Ecological factors are likely drivers of eye shape and colour pattern variations across anthropoid primates.
Article in Scientific reports, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 12 papers.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
12 citing papers in PubMed, 22 citations in OpenAlex.
- Rhesus monkeys use both eye and head gaze to reallocate covert spatial attention facilitating visual perception.Cognitive, affective & behavioral neuroscience · 2026Article
- Gaze in context: non-human eyes can be more salient under ecologically relevant conditions.Evolutionary human sciences · 2026Article
- Ultraviolet association with vernal keratoconjunctivitis with perilimbal pigmentation.International journal of ophthalmology · 2026Review
- Scleral exposure influences social judgments of trustworthiness, attractiveness, sociability, and social rank in White faces.PloS one · 2026Article
- Look past the cooperative eye hypothesis: reconsidering the evolution of human eye appearance.Biological reviews of the Cambridge Philosophical Society · 2025Review
- Photoregulatory functions drive variation in eye coloration across macaque species.Scientific reports · 2024Article
- Preliminary evidence that eye appearance in parrots (Psittaciformes) co-varies with latitude and altitude.Scientific reports · 2024Article
- Are dark-eyed dogs favoured by humans? Domestication as a potential driver of iris colour difference between dogs and wolves.Royal Society open science · 2023Article
- Scleral appearance is not a correlate of domestication in mammals.Zoological letters · 2023Article
- White sclera is present in chimpanzees and other mammals.Journal of human evolution · 2023Article
- Is there no beauty in sexually dimorphic eyes? Facial attractiveness and White Europeans ocular morphology-Brief communication.PloS one · 2023Article
- The adaptive significance of human scleral brightness: an experimental study.Scientific reports · 2022Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
5 authors at 5 institutions in 3 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
External eye appearance across primate species is diverse in shape and colouration, yet we still lack an explanation for the drivers of such diversity. Here we quantify substantial interspecific variation in eye shape and colouration across 77 primate species representing all extant genera of anthropoid primates. We reassess a series of hypotheses aiming to explain ocular variation in horizontal elongation and in colouration across species. Heavier body weight and terrestrial locomotion are associated with elongated eye outlines. Species living closer to the equator present more pigmented conjunctivae, suggesting photoprotective functions. Irises become bluer in species living further away from the equator, adding to existing literature supporting a circadian clock function for bluer irises. These results shift the current focus from communicative, to ecological factors in driving variation in external eye appearance in anthropoid primates. They also highlight the possibility that similar ecological factors contributed to selection for blue eyes in ancestral human populations living in northern latitudes.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.