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Ebel SJ, Völter CJ, Sánchez-Amaro A, Helming KA, Herrmann E, Call J. Functional fixedness in chimpanzees. Sci Rep 2024; 14:12155. [PMID: 38802445 PMCID: PMC11130300 DOI: 10.1038/s41598-024-62685-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 05/20/2024] [Indexed: 05/29/2024] Open
Abstract
Differences in the tool use of non-human primates and humans are subject of ongoing debate. In humans, representations of object functions underpin efficient tool use. Yet, representations of object functions can lead to functional fixedness, which describes the fixation on a familiar tool function leading to less efficient problem solving when the problem requires using the tool for a new function. In the current study, we examined whether chimpanzees exhibit functional fixedness. After solving a problem with a tool, chimpanzees were less efficient in solving another problem which required using the same tool with a different function compared to a control group. This fixation effect was still apparent after a period of nine months and when chimpanzees had learned about the function of a tool by observation of a conspecific. These results suggest that functional fixedness in our closest living relatives likely exists and cast doubt on the notion that stable function representations are uniquely human.
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Affiliation(s)
- Sonja J Ebel
- Department of Comparative Cultural Psychology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.
- Human Biology and Primate Cognition, Institute of Biology, Leipzig University, Leipzig, Germany.
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, United Kingdom.
| | - Christoph J Völter
- Department of Comparative Cultural Psychology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- Messerli Research Institute, University of Veterinary Medicine Vienna, Medical University of Vienna, University of Vienna, Vienna, Austria
| | - Alejandro Sánchez-Amaro
- Department of Comparative Cultural Psychology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- Division of Psychology, Faculty of Natural Sciences, University of Stirling, Stirling, United Kingdom
| | | | - Esther Herrmann
- Department of Psychology, University of Portsmouth, Portsmouth, United Kingdom
| | - Josep Call
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, United Kingdom
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Malherbe M, Samuni L, Ebel SJ, Kopp KS, Crockford C, Wittig RM. Protracted development of stick tool use skills extends into adulthood in wild western chimpanzees. PLoS Biol 2024; 22:e3002609. [PMID: 38713644 DOI: 10.1371/journal.pbio.3002609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 03/28/2024] [Indexed: 05/09/2024] Open
Abstract
Tool use is considered a driving force behind the evolution of brain expansion and prolonged juvenile dependency in the hominin lineage. However, it remains rare across animals, possibly due to inherent constraints related to manual dexterity and cognitive abilities. In our study, we investigated the ontogeny of tool use in chimpanzees (Pan troglodytes), a species known for its extensive and flexible tool use behavior. We observed 70 wild chimpanzees across all ages and analyzed 1,460 stick use events filmed in the Taï National Park, Côte d'Ivoire during the chimpanzee attempts to retrieve high-nutrient, but difficult-to-access, foods. We found that chimpanzees increasingly utilized hand grips employing more than 1 independent digit as they matured. Such hand grips emerged at the age of 2, became predominant and fully functional at the age of 6, and ubiquitous at the age of 15, enhancing task accuracy. Adults adjusted their hand grip based on the specific task at hand, favoring power grips for pounding actions and intermediate grips that combine power and precision, for others. Highly protracted development of suitable actions to acquire hidden (i.e., larvae) compared to non-hidden (i.e., nut kernel) food was evident, with adult skill levels achieved only after 15 years, suggesting a pronounced cognitive learning component to task success. The prolonged time required for cognitive assimilation compared to neuromotor control points to selection pressure favoring the retention of learning capacities into adulthood.
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Affiliation(s)
- Mathieu Malherbe
- Ape Social Mind Lab, Institut des Sciences Cognitives Marc Jeannerod, UMR5229 CNRS, Lyon, France
- Department of Human Behavior, Ecology and Culture, MPI for Evolutionary Anthropology, Leipzig, Germany
- Taï Chimpanzee Project, CSRS, Abidjan, Côte d'Ivoire
| | - Liran Samuni
- Taï Chimpanzee Project, CSRS, Abidjan, Côte d'Ivoire
- Cooperative Evolution Lab, German Primate Center, Göttingen, Germany
- Department of Human Evolutionary Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Sonja J Ebel
- Comparative Cultural Psychology, MPI for Evolutionary Anthropology, Leipzig, Germany
- Human Biology & Primate Cognition, Institute of Biology, Leipzig University, Leipzig, Germany
| | - Kathrin S Kopp
- Comparative Cultural Psychology, MPI for Evolutionary Anthropology, Leipzig, Germany
- Human Biology & Primate Cognition, Institute of Biology, Leipzig University, Leipzig, Germany
| | - Catherine Crockford
- Ape Social Mind Lab, Institut des Sciences Cognitives Marc Jeannerod, UMR5229 CNRS, Lyon, France
- Taï Chimpanzee Project, CSRS, Abidjan, Côte d'Ivoire
| | - Roman M Wittig
- Ape Social Mind Lab, Institut des Sciences Cognitives Marc Jeannerod, UMR5229 CNRS, Lyon, France
- Department of Human Behavior, Ecology and Culture, MPI for Evolutionary Anthropology, Leipzig, Germany
- Taï Chimpanzee Project, CSRS, Abidjan, Côte d'Ivoire
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Hayashi M. Introduction to "Evolutionary origins of human language: Hierarchical complexity and communicative signals". Primates 2022; 63:397-401. [PMID: 36006526 DOI: 10.1007/s10329-022-01013-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 08/05/2022] [Indexed: 10/15/2022]
Affiliation(s)
- Misato Hayashi
- Chubu Gakuin University, 30-1 Naka Oida-cho, Kakamigahara, Gifu, 504-0837, Japan. .,Japan Monkey Centre, Inuyama, Aichi, Japan.
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