Evidence map›Paper›PMID 42389374›Full record

ArticleEvolutionary human sciences2026

Gaze in context: non-human eyes can be more salient under ecologically relevant conditions.

Juan Olvido Perea García, Fumihiro Kano, Marta Sibierska, Vojtěch Fiala, Marta K Skrok, Dariusz P Danel, Ewa Katarzyna Ratajczak, Przemyslaw Zywiczynski, Slawomir Wacewicz

Abstract read
In one paragraph

Article in Evolutionary human sciences, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

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.

2 · The registry

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.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

9 authors.

Juan Olvido Perea GarcíaCenter for Language Evolution Studies, Nicolaus Copernicus University, Toruń, Poland.ORCID https://orcid.org/0000-0001-6559-0652
Fumihiro KanoCenter for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany.
Marta SibierskaCenter for Language Evolution Studies, Nicolaus Copernicus University, Toruń, Poland.
Vojtěch FialaCenter for Language Evolution Studies, Nicolaus Copernicus University, Toruń, Poland.ORCID https://orcid.org/0000-0002-0148-5092
Marta K SkrokInstitute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń, Toruń, Poland.
Dariusz P DanelDepartment of Anthropology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland.
Ewa Katarzyna RatajczakInstitute of Advanced Studies, Nicolaus Copernicus University in Toruń, Toruń, Poland.
Przemyslaw ZywiczynskiCenter for Language Evolution Studies, Nicolaus Copernicus University, Toruń, Poland.
Slawomir WacewiczCenter for Language Evolution Studies, Nicolaus Copernicus University, Toruń, Poland.ORCID https://orcid.org/0000-0003-1488-6220

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Primate eyes vary strikingly in pigmentation, yet the drivers of said variation are strongly debated. Recent revisions of the cooperative eye hypothesis propose that the human eye's sclera evolved to enhance gaze communication specifically under challenging conditions of visibility. We tested this idea under ecologically realistic conditions by presenting observers with a live model wearing contact lenses that simulated either a human-like or a chimpanzee-like eye. At a university lab, observers judged gaze direction at different viewing distances and lighting levels. We found no overall difference in efficacy of different eye types. Contrary to expectations, chimpanzee-like eyes outperformed human-like eyes in dim lighting and close-viewing conditions. Human-like eyes yielded the highest accuracy under bright, far-viewing conditions, consistent with a long-distance signalling advantage. Our results demonstrate that ecological visual constraints shape the potential informativeness of distinct ocular configurations. We hypothesize that species-typical eye appearances may be tuned to their species-typical visual ecology.

Indexed as

colourationcommunicationeye-gazeirissclera

Identifiers

PMID42389374
PMCPMC13319479

What Socratic holds

Textmetadata
LicenceCC BY
Read underepoch 390

Registered trials

None linked

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 Socratic graph.