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Zeiträg C, Jensen TR, Osvath M. Gaze following: A socio-cognitive skill rooted in deep time. Front Psychol 2022; 13:950935. [PMID: 36533020 PMCID: PMC9756811 DOI: 10.3389/fpsyg.2022.950935] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 10/07/2022] [Indexed: 11/07/2023] Open
Abstract
Social gaze has received much attention in social cognition research in both human and non-human animals. Gaze following appears to be a central skill for acquiring social information, such as the location of food and predators, but can also draw attention to important social interactions, which in turn promotes the evolution of more complex socio-cognitive processes such as theory of mind and social learning. In the past decades, a large number of studies has been conducted in this field introducing differing methodologies. Thereby, various factors influencing the results of gaze following experiments have been identified. This review provides an overview of the advances in the study of gaze following, but also highlights some limitations within the research area. The majority of gaze following studies on animals have focused on primates and canids, which limits evolutionary interpretations to only a few and closely related evolutionary lineages. This review incorporates new insights gained from previously understudied taxa, such as fishes, reptiles, and birds, but it will also provide a brief outline of mammal studies. We propose that the foundations of gaze following emerged early in evolutionary history. Basic, reflexive co-orienting responses might have already evolved in fishes, which would explain the ubiquity of gaze following seen in the amniotes. More complex skills, such as geometrical gaze following and the ability to form social predictions based on gaze, seem to have evolved separately at least two times and appear to be correlated with growing complexity in brain anatomy such as increased numbers of brain neurons. However, more studies on different taxa in key phylogenetic positions are needed to better understand the evolutionary history of this fundamental socio-cognitive skill.
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Affiliation(s)
- Claudia Zeiträg
- Department of Philosophy and Cognitive Science, Lund University, Lund, Sweden
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Caspar KR, Biggemann M, Geissmann T, Begall S. Ocular pigmentation in humans, great apes, and gibbons is not suggestive of communicative functions. Sci Rep 2021; 11:12994. [PMID: 34155285 PMCID: PMC8217224 DOI: 10.1038/s41598-021-92348-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 06/09/2021] [Indexed: 11/23/2022] Open
Abstract
Pigmentation patterns of the visible part of the eyeball, encompassing the iris and portions of the sclera, have been discussed to be linked to social cognition in primates. The cooperative eye hypothesis suggests the white sclera of humans to be a derived adaptive trait that enhances eye-mediated communication. Here, we provide a comparative analysis of ocular pigmentation patterns in 15 species of hominoids (humans, great apes & gibbons) that show marked differences in social cognition and quantify scleral exposure at the genus level. Our data reveals a continuum of eye pigmentation traits in hominoids which does not align with the complexity of gaze-mediated communication in the studied taxa. Gibbons display darker eyes than great apes and expose less sclera. Iridoscleral contrasts in orangutans and gorillas approach the human condition but differ between congeneric species. Contrary to recent discussions, we found chimpanzee eyes to exhibit a cryptic coloration scheme that resembles gibbons more than other apes. We reevaluate the evidence for links between social cognition and eye pigmentation in primates, concluding that the cooperative eye hypothesis cannot explain the patterns observed. Differences in scleral pigmentation between great apes and humans are gradual and might have arisen via genetic drift and sexual selection.
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Affiliation(s)
- Kai R Caspar
- Department of General Zoology, University of Duisburg-Essen, Universitaetsstraße 5, 45141, Essen, Germany.
| | - Marco Biggemann
- Department of General Zoology, University of Duisburg-Essen, Universitaetsstraße 5, 45141, Essen, Germany
| | - Thomas Geissmann
- Anthropological Institute, University Zurich-Irchel, Winterthurerstraße 190, 8057, Zurich, Switzerland
| | - Sabine Begall
- Department of General Zoology, University of Duisburg-Essen, Universitaetsstraße 5, 45141, Essen, Germany
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Sánchez-Amaro A, Ball R, Rossano F. Gibbon strategies in a food competition task. Sci Rep 2021; 11:9312. [PMID: 33927301 PMCID: PMC8085081 DOI: 10.1038/s41598-021-88804-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 04/14/2021] [Indexed: 02/03/2023] Open
Abstract
Social primates face conflicts of interest with other partners when their individual and collective interests collide. Despite living in small, primarily bonded, groups compared to other social primates, gibbons are not exempt from these conflicts in their everyday lives. In the current task, we asked whether dyads of gibbons would solve a conflict of interest over food rewards. We presented dyads of gibbons with a situation in which they could decide whether to take an active role and pull a handle to release food rewards at a distance or take a passive role and avoid action. In this situation, the passive partner could take an advantageous position to obtain the rewards over the active partner. Gibbons participated in three conditions: a control condition with no food rewards, a test condition with indirect food rewards and a test condition with direct food rewards. In both test conditions, five rewards were released at a distance from the handle. In addition, the active individual could obtain one extra food reward from the handle in the direct food condition. We found that gibbons acted more often in the two conditions involving food rewards, and waited longer in the indirect compared to the direct food condition, thus suggesting that they understood the task contingencies. Surprisingly, we found that in a majority of dyads, individuals in the active role obtained most of the payoff compared to individuals in the passive role in both food conditions. Furthermore, in some occasions individuals in the active role did not approach the location where the food was released. These results suggest that while gibbons may strategize to maximize benefits in a competitive food task, they often allowed their partners to obtain better rewards. Our results highlight the importance of social tolerance and motivation as drivers promoting cooperation in these species.
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Affiliation(s)
- Alejandro Sánchez-Amaro
- grid.266100.30000 0001 2107 4242Department of Cognitive Science, University of California San Diego, La Jolla, USA ,grid.419518.00000 0001 2159 1813Department of Comparative Cultural Psychology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Robert Ball
- grid.266100.30000 0001 2107 4242Department of Cognitive Science, University of California San Diego, La Jolla, USA ,grid.212340.60000000122985718The Graduate Center, City University of New York, New York, USA
| | - Federico Rossano
- grid.266100.30000 0001 2107 4242Department of Cognitive Science, University of California San Diego, La Jolla, USA
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Castellano-Navarro A, Macanás-Martínez E, Xu Z, Guillén-Salazar F, MacIntosh AJJ, Amici F, Albiach-Serrano A. Japanese Macaques' (Macaca fuscata) sensitivity to human gaze and visual perspective in contexts of threat, cooperation, and competition. Sci Rep 2021; 11:5264. [PMID: 33664316 PMCID: PMC7933183 DOI: 10.1038/s41598-021-84250-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 02/10/2021] [Indexed: 11/26/2022] Open
Abstract
Gaze sensitivity allows us to interpret the visual perspective of others, inferring their intentions and attentional states. In order to clarify the evolutionary history of this ability, we assessed the response of free-ranging Japanese macaques (Macaca fuscata) to human gaze in three contexts: threat (Experiment 1), cooperation (Experiment 2), and competition (Experiment 3). Subjects interpreted the direct gaze of an approaching human as a sign of threat, showing a greater flight initiation distance and more threats towards the human in this condition than when the human gazed in another direction. Subjects also adapted their behavior to the attentional cues of a human who gave them food, by for example moving into his visual field. However, the macaques did not seem to take the visual perspective of a human competing with them over food, as they failed to first retrieve the food that was not visible to the human (i.e., located behind an opaque barrier). Our results support the idea that Japanese macaques can respond to a human’s gaze flexibly depending on the context. Moreover, they highlight the importance of studying animal behavior across different species and contexts to better understand the selective pressures that might have led to its evolution.
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Affiliation(s)
- Alba Castellano-Navarro
- Ethology and Animal Welfare Section, Universidad Cardenal Herrera-CEU, CEU Universities, Tirant lo Blanc 7, 46115, Alfara del Patriarca, Valencia, Spain.
| | - Emilio Macanás-Martínez
- Ethology and Animal Welfare Section, Universidad Cardenal Herrera-CEU, CEU Universities, Tirant lo Blanc 7, 46115, Alfara del Patriarca, Valencia, Spain
| | - Zhihong Xu
- Primate Research Institute, Kyoto University, Kanrin 41-2, Inuyama, Aichi, 484-8506, Japan
| | - Federico Guillén-Salazar
- Ethology and Animal Welfare Section, Universidad Cardenal Herrera-CEU, CEU Universities, Tirant lo Blanc 7, 46115, Alfara del Patriarca, Valencia, Spain
| | - Andrew J J MacIntosh
- Primate Research Institute, Kyoto University, Kanrin 41-2, Inuyama, Aichi, 484-8506, Japan
| | - Federica Amici
- Research Group Primate Behavioral Ecology, Department of Human Behavior, Ecology and Culture, Max-Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103, Leipzig, Germany.,Behavioral Ecology Research Group, Institute of Biology, Faculty of Life Science, University of Leipzig, Talstraße 33, 04103, Leipzig, Germany
| | - Anna Albiach-Serrano
- Ethology and Animal Welfare Section, Universidad Cardenal Herrera-CEU, CEU Universities, Tirant lo Blanc 7, 46115, Alfara del Patriarca, Valencia, Spain
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