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Delval I, Fernández-Bolaños M, Izar P. Towards an Integrated Concept of Personality in Human and Nonhuman Animals. Integr Psychol Behav Sci 2024; 58:271-302. [PMID: 37059965 PMCID: PMC10104772 DOI: 10.1007/s12124-023-09759-y] [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] [Accepted: 03/21/2023] [Indexed: 04/16/2023]
Abstract
Every individual has an idiosyncratic way of feeling, thinking and behaving, which is relatively stable across time and situations. Usually known as Personality, today this phenomenon is recognized in many species, including arthropods, fish, avian or mammals. From an evolutionary perspective, research has shown that personality differences are manifest in distinctive forms of dealing with selective pressures, with consequences for fitness. Despite these facts, the study of personality in animals other than humans is relatively new. Only two decades ago, consistent behavioral individual differences were considered 'noise' around an optimal strategy for behavioral ecologists. Also, psychologists were not interested in animal personality as a consequence of the fear of anthropomorphization and the erroneous belief that humans are unique in nature. Fortunately, this misconception seems already overcome but there are still conceptual issues preventing a unified concept of personality. Throughout this review, we first explore the etymological origins of personality and other terminological issues. We further revise the historical course of the study of personality in humans and other animals, from the perspectives of Psychology and Behavioral Ecology, on the basis of the most used approach, the trait theory. We present the study of nonhuman primates as a paradigmatic example in between both frameworks. Finally, we discuss about the necessity of a unified science of personality.
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Affiliation(s)
- Irene Delval
- Department of Experimental Psychology, Institute of Psychology, University of São Paulo (IP-USP). Av. Prof. Mello Moraes 1721, São Paulo, SP, CEP 05508-030, Brazil.
| | - Marcelo Fernández-Bolaños
- Department of Experimental Psychology, Institute of Psychology, University of São Paulo (IP-USP). Av. Prof. Mello Moraes 1721, São Paulo, SP, CEP 05508-030, Brazil
| | - Patrícia Izar
- Department of Experimental Psychology, Institute of Psychology, University of São Paulo (IP-USP). Av. Prof. Mello Moraes 1721, São Paulo, SP, CEP 05508-030, Brazil
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Omena J, Izar P. Ontogenesis of sociability of wild immature capuchin monkeys (Sapajus libidinosus): Sex more than personality explains interindividual variation. Am J Primatol 2023; 85:e23533. [PMID: 37394768 DOI: 10.1002/ajp.23533] [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: 09/11/2022] [Revised: 06/16/2023] [Accepted: 06/19/2023] [Indexed: 07/04/2023]
Abstract
Sociability is a fundamental trait that social animals need to survive and reproduce in societies. Sociability predicts how an individual can consistently interact with its conspecifics across time and situations. By studying capuchin monkeys (Sapajus libidinosus), a neotropical primate with complex social behavior and high cognitive capacity, our research aims to analyze the development of the social axis of personality of immature individuals, from birth to the third year of life. We studied wild monkeys belonging to a group with infants, juveniles, and adults of both sexes that inhabits northeastern Brazil. We analyzed the behavior of 12 immature capuchins (6 males and 6 females) in 94 h of videos recorded weekly from birth until 36 months, through daily focal sampling. We verified whether there was intraindividual consistency throughout development by fitting regression models for the effect of age on initiating affiliative social behaviors, controlling for monkey identity and sex. Our results indicate that the individuals of this study exhibit high variation in the initiation of behaviors at the beginning of infancy; there was low repeatability and high intra-individual variation during the first 3 years of life of these individuals, indicating that the social personality is not consolidated in this period. Immature females were more sociable than immature males. Therefore, differences in sociability in early life of bearded capuchin monkeys are best explained by sex rather than personality. We suggest that the high initial behavioral variation in the social axis of personality allows for plasticity influenced by the environment throughout development. The high sociability of females in infancy may be related to female philopatry and their high sociability in adulthood.
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Affiliation(s)
- Julia Omena
- Institute of Psychology, University of São Paulo, São Paulo, Brazil
| | - Patrícia Izar
- Institute of Psychology, University of São Paulo, São Paulo, Brazil
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Masilkova M, Šlipogor V, Lima Marques Silva GH, Hadová M, Lhota S, Bugnyar T, Konečná M. Age, but not hand preference, is related to personality traits in common marmosets ( Callithrix jacchus). ROYAL SOCIETY OPEN SCIENCE 2022; 9:220797. [PMID: 36300134 PMCID: PMC9579762 DOI: 10.1098/rsos.220797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 09/29/2022] [Indexed: 06/16/2023]
Abstract
The proximate mechanisms underlying animal personalities, i.e. consistent inter-individual differences in behaviour, are a matter of discussion. Brain lateralization, expressed as the preferred use of the contralateral limb, has been suggested as one of these mechanisms. In this study, we measured a proxy of brain lateralization in captive common marmosets (N = 28) by testing hand preference in a simple food-reaching task and evaluated personality by coding a wide range of behaviours observed in daily situations. We explored the links between personality and both direction and strength of hand preference, as well as age and sex, using linear models. Principal component analysis revealed that the stable behavioural variables were organized in three personality dimensions: Agreeableness, Extraversion and Neuroticism. Regarding hand preference, 14 individuals were left-handed, seven were right-handed and seven were ambilateral. Contrary to our predictions, we did not find any relationship between personality scores and hand preference or sex. Instead, age was a significant predictor of personality scores, with older individuals being more agreeable and less extraverted. The link between brain lateralization and personality seems to be equivocal and dependent on personality and brain lateralization assessment methods. Further examinations of other proximate mechanisms, such as physiology or (epi)genetics, may elucidate what drives personality variation in common marmosets.
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Affiliation(s)
- Michaela Masilkova
- Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Prague, Czech Republic
- Department of Zoology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Vedrana Šlipogor
- Department of Zoology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | | | - Magdaléna Hadová
- Department of Zoology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
- Bratislava Zoo, Bratislava, Slovakia
| | - Stanislav Lhota
- Department of Animal Science and Food Processing, Faculty of Tropical AgriSciences, Czech University of Life Sciences, Prague, Czech Republic
- Ústí nad Labem Zoo, Ústí nad Labem, Czech Republic
| | - Thomas Bugnyar
- Department of Behavioral and Cognitive Biology, Faculty of Life Sciences, University of Vienna, Vienna, Austria
| | - Martina Konečná
- Department of Zoology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
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Charles A, Henaut Y, Saint Jalme M, Mulot B, Lecu A, Delfour F. Studying Antillean manatees’ (Trichechus manatus manatus) temperament in zoological parks: exploration of boldness, sociality and reactivity to humans. Appl Anim Behav Sci 2022. [DOI: 10.1016/j.applanim.2021.105512] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Norman M, Rowden LJ, Cowlishaw G. Potential applications of personality assessments to the management of non-human primates: a review of 10 years of study. PeerJ 2021; 9:e12044. [PMID: 34589296 PMCID: PMC8432321 DOI: 10.7717/peerj.12044] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 08/02/2021] [Indexed: 12/19/2022] Open
Abstract
Studies of primate personality have become increasingly common over the past three decades. Recently, studies have begun to focus on the health, welfare and conservation implications of personality, and the potential applications of incorporating quantitative personality assessments into animal management programmes. However, this literature is dispersed across a multitude of settings and scientific disciplines. We conducted a review of nonhuman primate personality studies relevant to these issues published since 2010, following on from an earlier review. The databases ScienceDirect, PubMed and Web of Science were used to identify relevant articles. After eliminating irrelevant or duplicate papers, 69 studies were selected. Our review reveals that, while primate personality research is carried out on a range of species, there is strong taxonomic bias. While 28 species appeared within the reviewed literature, 52% of studies were carried out on just five species. Further, the most common research focus (43%) was validating new assessment methods or describing personality in different species, rather than exploring the links between personality and animal welfare using existing validated methods. However, among the remaining studies that did explore the role of animal personality in husbandry, health, and welfare, we identified progression towards integrating personality data into various aspects of animal management. Evidence suggests the assessment of personality may benefit social group management, enrichment practices, training protocols, health and welfare monitoring, and conservation planning for endangered species. We argue that further research which develops our understanding of primate personality and its influence in these areas will provide a valuable tool to inform animal management practices.
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Affiliation(s)
- Max Norman
- Royal Veterinary College, London, United Kingdom.,Institute of Zoology, Zoological Society of London, London, United Kingdom
| | | | - Guy Cowlishaw
- Institute of Zoology, Zoological Society of London, London, United Kingdom
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Šlipogor V, Massen JJM, Schiel N, Souto A, Bugnyar T. Temporal consistency and ecological validity of personality structure in common marmosets (Callithrix jacchus): A unifying field and laboratory approach. Am J Primatol 2021; 83:e23229. [PMID: 33464603 PMCID: PMC7900989 DOI: 10.1002/ajp.23229] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 11/19/2020] [Accepted: 12/21/2020] [Indexed: 12/28/2022]
Abstract
Personality in animals has been extensively researched in recent decades. Temporal consistency of behaviors is almost always part of the personality definition and is usually explored in several different testing sessions or observation periods. However, it is still unclear whether the obtained personality constructs are stable across several years, which might be especially important for long-living animals, such as primates. Further, little is known on whether the personality structures obtained in the laboratory reflect the structures obtained under ecologically relevant conditions in the wild. Therefore, we conducted a battery of personality tests on common marmosets (Callithrix jacchus) (N = 27), compared it with a test battery conducted 4 years beforehand on a subset of animals in captivity (N = 13) and ran an adapted version under field conditions at Baracuhy Biological Field Station, Brazil (N = 18). Under captive conditions, we found a remarkably similar personality structure across 4 testing years. Further, we found high long-term temporal consistency in the first two personality components, Boldness and Exploration; however, monkeys that changed their social (i.e., breeding) status between the two testing periods showed a significant increase in Boldness scores. Under field conditions, we found a somewhat similar personality structure as compared to the laboratory, which to some extent corroborates ecological validity of our personality test design. Nevertheless, whether the structure in the wild is suppressed or expanded in comparison to captivity, and in which way the social setting influences personality structure, should be further explored. Taken together, our results contribute to the discussion about the reliability and ecological validity of personality structures in nonhuman primates.
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Affiliation(s)
- Vedrana Šlipogor
- Department of Behavioral and Cognitive BiologyUniversity of ViennaViennaAustria
- Department of BiologyFederal Rural University of PernambucoRecifeBrazil
- Department of ZoologyFederal University of PernambucoRecifeBrazil
| | - Jorg J. M. Massen
- Department of Behavioral and Cognitive BiologyUniversity of ViennaViennaAustria
- Animal Ecology Group, Institute of Environmental Biology, Department of BiologyUtrecht UniversityUtrechtThe Netherlands
| | - Nicola Schiel
- Department of BiologyFederal Rural University of PernambucoRecifeBrazil
| | - Antonio Souto
- Department of ZoologyFederal University of PernambucoRecifeBrazil
| | - Thomas Bugnyar
- Department of Behavioral and Cognitive BiologyUniversity of ViennaViennaAustria
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Delval I, Fernández-Bolaños M, Izar P. A longitudinal assessment of behavioral development in wild capuchins: Personality is not established in the first 3 years. Am J Primatol 2020; 82:e23116. [PMID: 32096276 DOI: 10.1002/ajp.23116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 02/01/2020] [Accepted: 02/09/2020] [Indexed: 12/25/2022]
Abstract
Animal personality is defined as consistent individual differences across time and situations, but little is known about how or when those differences are established during development. Likewise, several studies described the personality structure of adult capuchin monkeys, without assessing the ontogeny of these personality traits. We analyzed the behavioral repertoire of 12 wild infants (9 males, 3 females) yellow-breasted capuchin monkeys (Sapajus xanthosternos), in Una Biological Reserve (Bahia, Brazil). Each infant was observed and filmed weekly from birth until 36 months, through daily focal sampling. We analyzed the behavior of each individual in 10 developmental points. By means of component reduction (principal component analysis), we obtained four behavioral traits: Sociability, Anxiety, Openness, and Activity. We investigated whether there were developmental effects on those traits by fitting regression models for the effect of time on behavioral traits, controlling for monkey identity, sex, and cohort. Sociability (decreasing) and Anxiety (increasing) changed significantly along development. By means of repeatability analysis, we did not find intra-individual consistency across time in those traits, so we cannot discriminate stable personality traits in early ontogeny. Our results show that the personality structure of capuchin monkeys is not established during early development, in agreement with the literature on human personality.
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Affiliation(s)
- Irene Delval
- Department of Experimental Psychology, Institute of Psychology, University of São Paulo (IP-USP), São Paulo, SP, Brazil
| | - Marcelo Fernández-Bolaños
- Department of Experimental Psychology, Institute of Psychology, University of São Paulo (IP-USP), São Paulo, SP, Brazil
| | - Patrícia Izar
- Department of Experimental Psychology, Institute of Psychology, University of São Paulo (IP-USP), São Paulo, SP, Brazil
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