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Roth TS, Samara I, Perea-Garcia JO, Kret ME. No immediate attentional bias towards or choice bias for male secondary sexual characteristics in Bornean orang-utans (Pongo pygmaeus). Sci Rep 2024; 14:12095. [PMID: 38802458 PMCID: PMC11130206 DOI: 10.1038/s41598-024-62187-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 05/14/2024] [Indexed: 05/29/2024] Open
Abstract
Primate faces provide information about a range of variant and invariant traits, including some that are relevant for mate choice. For example, faces of males may convey information about their health or genetic quality through symmetry or facial masculinity. Because perceiving and processing such information may have bearing on the reproductive success of an individual, cognitive systems are expected to be sensitive to facial cues of mate quality. However, few studies have investigated this topic in non-human primate species. Orang-utans are an interesting species to test mate-relevant cognitive biases, because they are characterised by male bimaturism: some adult males are fully developed and bear conspicuous flanges on the side of their face, while other males look relatively similar to females. Here, we describe two non-invasive computerised experiments with Bornean orang-utans (Pongo pygmaeus), testing (i) immediate attention towards large flanges and symmetrical faces using a dot-probe task (N = 3 individuals; 2F) and (ii) choice bias for pictures of flanged males over unflanged males using a preference test (N = 6 individuals; 4F). In contrast with our expectations, we found no immediate attentional bias towards either large flanges or symmetrical faces. In addition, individuals did not show a choice bias for stimuli of flanged males. We did find exploratory evidence for a colour bias and energy efficiency trade-offs in the preference task. We discuss our null results and exploratory results in the context of the evolutionary history of Bornean orang-utans, and provide suggestions for a more biocentric approach to the study of orang-utan cognition.
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Affiliation(s)
- Tom S Roth
- Cognitive Psychology Unit, Institute of Psychology, The Faculty of Social and Behavioral Sciences, Leiden University, Wassenaarseweg 52, 2333 AK, Leiden, The Netherlands.
- Apenheul Primate Park, J.CWilslaan 21, 7313 HK, Apeldoorn, The Netherlands.
- Animal Behaviour & Cognition, Department of Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
| | - Iliana Samara
- Cognitive Psychology Unit, Institute of Psychology, The Faculty of Social and Behavioral Sciences, Leiden University, Wassenaarseweg 52, 2333 AK, Leiden, The Netherlands
- Leiden Institute of Brain and Cognition (LIBC), Leiden, The Netherlands
| | - Juan Olvido Perea-Garcia
- Cognitive Psychology Unit, Institute of Psychology, The Faculty of Social and Behavioral Sciences, Leiden University, Wassenaarseweg 52, 2333 AK, Leiden, The Netherlands
| | - Mariska E Kret
- Cognitive Psychology Unit, Institute of Psychology, The Faculty of Social and Behavioral Sciences, Leiden University, Wassenaarseweg 52, 2333 AK, Leiden, The Netherlands
- Leiden Institute of Brain and Cognition (LIBC), Leiden, The Netherlands
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Kret ME. Gaze into social bonds: Unlocking great ape emotions through eye-tracking. Proc Natl Acad Sci U S A 2024; 121:e2319953121. [PMID: 38147565 PMCID: PMC10769836 DOI: 10.1073/pnas.2319953121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2023] Open
Affiliation(s)
- Mariska E. Kret
- Cognitive Psychology Unit, Institute of Psychology, Faculty of Social Sciences, Leiden University, Leiden2333 AK, Netherlands
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Rogers FD, Bales KL. Introduction to Special Issue on Affective Science in Animals: Toward a Greater Understanding of Affective Processes in Non-Human Animals. AFFECTIVE SCIENCE 2022; 3:697-702. [PMID: 36514490 PMCID: PMC9734565 DOI: 10.1007/s42761-022-00168-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 11/21/2022] [Indexed: 12/04/2022]
Abstract
How should we characterize the affective lives of non-human animals? There is a large body of work studying affective processes in non-human animals, yet this work is frequently overlooked. Ideas about the affective lives of animals have varied across culture and time and are reflected in literature, theology, and philosophy. Our contemporary ideas about animal affect are philosophically important within the discipline of affective science, and these ideas have consequences in several domains, including animal husbandry, conservation, and human and veterinary medicine. The articles contained within this special volume cover several levels of analysis and broad representation of species, from the non-mammalian, to rodents, to primates; but together, these articles are collectively concerned with the topic of affective processes in non-human animals.
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Affiliation(s)
- Forrest D. Rogers
- Princeton Neuroscience Institute, Princeton, NJ USA ,Department of Molecular Biology, Princeton University, Princeton, NJ USA
| | - Karen L. Bales
- Department of Psychology, University of California, Davis, CA USA ,Department of Neurobiology, Physiology, and Behavior, University of California, Davis, CA 95616 USA ,California National Primate Research Center, Davis, CA USA
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