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Philosophical Transactions of the Royal... 2013Female chimpanzees exhibit exceptionally slow rates of reproduction and raise their offspring without direct paternal care. Therefore, their reproductive success depends... (Review)
Review
Female chimpanzees exhibit exceptionally slow rates of reproduction and raise their offspring without direct paternal care. Therefore, their reproductive success depends critically on long-term access to high-quality food resources over a long lifespan. Chimpanzee communities contain multiple adult males, multiple adult females and their offspring. Because males are philopatric and jointly defend the community range while most females transfer to new communities before breeding, adult females are typically surrounded by unrelated competitors. Communities are fission-fusion societies in which individuals spend time alone or in fluid subgroups, whose size depends mostly on the abundance and distribution of food. To varying extents in different populations, females avoid direct competition by foraging alone or in small groups in distinct, but overlapping core areas within the community range to which they show high fidelity. Although rates of aggression are low, females compete for space and access to food. High rank correlates with high reproductive success, and high-ranking females win direct contests for food and gain preferential access to resource-rich sites. Females are aggressive to immigrant females and even kill the newborn infants of community members. The intensity of such aggression correlates with population density. These patterns are compared to those in other species, including humans.
Topics: Animals; Animals, Newborn; Behavior, Animal; Competitive Behavior; Female; Food Supply; Humans; Male; Pan troglodytes; Reproduction
PubMed: 24167307
DOI: 10.1098/rstb.2013.0077 -
PeerJ 2022Social play is ubiquitous in the development of many animal species and involves players adapting actions flexibly to their own previous actions and partner responses....
Social play is ubiquitous in the development of many animal species and involves players adapting actions flexibly to their own previous actions and partner responses. Play differs from other behavioural contexts for which fine-scale analyses of action sequences are available, such as tool use and communication, in that its form is not defined by its function, making it potentially more unpredictable. In humans, play is often organised in games, where players know context-appropriate actions but string them together unpredictably. Here, we use the sequential nature of play elements to explore whether play elements in chimpanzees are structured hierarchically and follow predictable game-like patterns. Based on 5,711 play elements from 143 bouts, we extracted individual-level play sequences of 11 Western chimpanzees () of different ages from the Bossou community. We detected transition probabilities between play elements that exceeded expected levels and show that play elements form hierarchically clustered and interchangeable groups, indicative of at least six games that can be identified from transition networks, some with different roles for different players. We also show that increased information about preceding play elements improved predictability of subsequent elements, further indicating that play elements are not strung together randomly but that flexible action rules underlie their usage. Thus, chimpanzee play is hierarchically structured in short games which limit acceptable play elements and allow players to predict and adapt to partners' actions. This "grammar of action" approach to social interactions can be valuable in understanding cognitive and communicative abilities within and across species.
Topics: Animals; Humans; Pan troglodytes; Feeding Behavior; Social Interaction; Communication
PubMed: 36411837
DOI: 10.7717/peerj.14294 -
Current Biology : CB Oct 2021Humans reason not only about actual events (what is), but also about possible events (what could be). Many key operations of human cognition involve the representation...
Humans reason not only about actual events (what is), but also about possible events (what could be). Many key operations of human cognition involve the representation of possibilities, including moral judgment, future planning, and causal understanding. But little is known about the evolutionary roots of this kind of thought. Humans' closest relatives, chimpanzees, possess several cognitive abilities that are closely related to reasoning about alternatives: they plan for the future, evaluate other's actions, and reason causally. However, in the first direct test of the ability to consider alternatives, Redshaw and Suddendorf claim that chimpanzees are not able to represent alternative possibilities. Here, using a novel method, we challenge this conclusion: our results suggest that, like human cognition, chimpanzee thought is not limited to what is, but also involves reasoning about what could be the case.
Topics: Animals; Cognition; Humans; Judgment; Morals; Pan troglodytes; Problem Solving
PubMed: 34699798
DOI: 10.1016/j.cub.2021.09.012 -
Proceedings. Biological Sciences Dec 2017Various non-human animal species have been shown to exhibit behavioural traditions. Importantly, this research has been guided by what we know of human culture, and the... (Review)
Review
Various non-human animal species have been shown to exhibit behavioural traditions. Importantly, this research has been guided by what we know of human culture, and the question of whether animal cultures may be homologous or analogous to our own culture. In this paper, we assess whether models of human cultural transmission are relevant to understanding biological fundamentals by investigating whether accounts of human payoff-biased social learning are relevant to chimpanzees (). We submitted 4- and 5-year-old children ( = 90) and captive chimpanzees ( = 69) to a token-reward exchange task. The results revealed different forms of payoff-biased learning across species and contexts. Specifically, following personal and social exposure to different tokens, children's exchange behaviour was consistent with proportional imitation, where choice is affected by both prior personally acquired and socially demonstrated token-reward information. However, when the socially derived information regarding token value was novel, children's behaviour was consistent with proportional observation; paying attention to socially derived information and ignoring their prior personal experience. By contrast, chimpanzees' token choice was governed by their own prior experience only, with no effect of social demonstration on token choice, conforming to proportional reservation. We also find evidence for individual- and group-level differences in behaviour in both species. Despite the difference in payoff strategies used, both chimpanzees and children adopted beneficial traits when available. However, the strategies of the children are expected to be the most beneficial in promoting flexible behaviour by enabling existing behaviours to be updated or replaced with new and often superior ones.
Topics: Animals; Child, Preschool; Choice Behavior; Female; Humans; Male; Pan troglodytes; Reward; Social Learning
PubMed: 29187629
DOI: 10.1098/rspb.2017.1751 -
Current Biology : CB Jan 2016The identification and recruitment of trustworthy partners represents an important adaptive challenge for any species that relies heavily on cooperation [1, 2]. From an...
The identification and recruitment of trustworthy partners represents an important adaptive challenge for any species that relies heavily on cooperation [1, 2]. From an evolutionary perspective, trust is difficult to account for as it involves, by definition, a risk of non-reciprocation and defection by cheaters [3, 4]. One solution for this problem is to form close emotional bonds, i.e., friendships, which enable trust even in contexts where cheating would be profitable [5]. Little is known about the evolutionary origins of the human tendency to form close social bonds to overcome the trust problem. Studying chimpanzees (Pan troglodytes), one of our closest living relatives, is one way of identifying these origins. While a growing body of research indicates that at least some of the properties of close human relationships find parallels in the social bonds of chimpanzees [6-10] and that chimpanzees extend favors preferentially toward selected individuals [11-14], it is unclear whether such interactions are based on trust. To fill this gap in knowledge, we observed the social interactions of a group of chimpanzees and established dyadic friendship relations. We then presented chimpanzees with a modified, non-verbal version of the human trust game and found that chimpanzees trust their friends significantly more frequently than their non-friends. These results suggest that trust within closely bonded dyads is not unique to humans but rather has its evolutionary roots in the social relationships of our closest primate relatives.
Topics: Animals; Behavior, Animal; Biological Evolution; Friends; Interpersonal Relations; Pan troglodytes; Social Behavior; Trust
PubMed: 26776735
DOI: 10.1016/j.cub.2015.11.037 -
Psychological Science Mar 2023Risk preference impacts how people make key life decisions related to health, wealth, and well-being. Systematic variations in risk-taking behavior can be the result of...
Risk preference impacts how people make key life decisions related to health, wealth, and well-being. Systematic variations in risk-taking behavior can be the result of differences in fitness expectations, as predicted by life-history theory. Yet the evolutionary roots of human risk-taking behavior remain poorly understood. Here, we studied risk preferences of chimpanzees (86 ; 47 females; age = 2-40 years) using a multimethod approach that combined observer ratings with behavioral choice experiments. We found that chimpanzees' willingness to take risks shared structural similarities with that of humans. First, chimpanzees' risk preference manifested as a traitlike preference that was consistent across domains and measurements. Second, chimpanzees were ambiguity averse. Third, males were more risk prone than females. Fourth, the appetite for risk showed an inverted-U-shaped relation to age and peaked in young adulthood. Our findings suggest that key dimensions of risk preference appear to emerge independently of the influence of human cultural evolution.
Topics: Animals; Female; Humans; Male; Pan troglodytes; Risk-Taking; Biological Evolution
PubMed: 36595467
DOI: 10.1177/09567976221140326 -
Proceedings of the National Academy of... Aug 2022
Topics: Aggression; Animals; Hostility; Pan paniscus; Pan troglodytes; Territoriality
PubMed: 35881798
DOI: 10.1073/pnas.2208865119 -
Current Biology : CB Jul 2014The role that genes play in human intelligence or IQ has remained a point of significant scientific debate dating back to the time of Galton [1]. It has now become...
The role that genes play in human intelligence or IQ has remained a point of significant scientific debate dating back to the time of Galton [1]. It has now become increasingly clear that IQ is heritable in humans, but these effects can be modified by nongenetic mechanisms [2-4]. In contrast to human IQ, until recently, views of learning and cognition in animals have largely been dominated by the behaviorist school of thought, originally championed by Watson [5] and Skinner [6]. A large body of accumulated research now demonstrates a variety of cognitive abilities in nonhuman animals and challenges traditional behaviorist interpretations of performance [7, 8]. This, in turn, has led to a renewed interest in the role that social and biological factors might play in explaining individual and phylogenetic differences in cognition [9]. Specifically, aside from early attempts to selectively breed for learning skills in rodents [10-12], studies examining the role that genetic factors might play in individual variation in cognitive abilities in nonhuman animals, particularly nonhuman primates, are scarce. Here, we utilized a modified Primate Cognitive Test Battery [13] in conjunction with quantitative genetic analyses to examine whether cognitive performance is heritable in chimpanzees. We found that some but not all cognitive traits were significantly heritable in chimpanzees. We further found significant genetic correlations between different dimensions of cognitive functioning, suggesting that the genes that explain the variability of one cognitive trait might also explain that of other cognitive traits.
Topics: Animals; Cognition; Female; Intelligence; Intelligence Tests; Learning; Male; Pan troglodytes; Principal Component Analysis
PubMed: 25017206
DOI: 10.1016/j.cub.2014.05.076 -
American Journal of Primatology Dec 2009The two species of Pan, bonobos and common chimpanzees, have been reported to have different social organization, cognitive and linguistic abilities and motor skill,... (Comparative Study)
Comparative Study
The two species of Pan, bonobos and common chimpanzees, have been reported to have different social organization, cognitive and linguistic abilities and motor skill, despite their close biological relationship. Here, we examined whether bonobos and chimpanzee differ in selected brain regions that may map to these different social and cognitive abilities. Eight chimpanzees and eight bonobos matched on age, sex and rearing experiences were magnetic resonance images scanned and volumetric measures were obtained for the whole brain, cerebellum, striatum, motor-hand area, hippocampus, inferior frontal gyrus and planum temporale. Chimpanzees had significantly larger cerebellum and borderline significantly larger hippocampus and putamen, after adjusting for brain size, compared with bonobos. Bonobos showed greater leftward asymmetries in the striatum and motor-hand area compared with chimpanzees. No significant differences in either the volume or lateralization for the so-called language homologs were found between species. The results suggest that the two species of Pan are quite similar neurologically, though some volumetric and lateralized differences may reflect inherent differences in social organization, cognition and motor skills.
Topics: Animal Communication; Animals; Brain; Female; Magnetic Resonance Imaging; Male; Motor Skills; Organ Size; Pan paniscus; Pan troglodytes; Social Behavior
PubMed: 19760676
DOI: 10.1002/ajp.20741 -
Current Biology : CB Feb 2018For humans, there appears to be a clear link between general intelligence and self-control behavior, such as sustained delay of gratification [1-9]. Chimpanzees also...
For humans, there appears to be a clear link between general intelligence and self-control behavior, such as sustained delay of gratification [1-9]. Chimpanzees also delay gratification [10-12] and can be given tests of general intelligence (g) [13-15], but these two constructs have never been compared within the same sample of nonhuman animals. We presented 40 chimpanzees with the hybrid delay task (HDT) [16, 17], which measures inter-temporal choices and the capacity for sustained delay of gratification, and the primate cognitive test battery (PCTB), which measures g in chimpanzees [13-15]. Importantly, none of the sub-tasks in the PCTB directly assesses self-control or other forms of behavioral inhibition. Rather, they assess areas of physical cognition (e.g., quantity discrimination) or social cognition (e.g., gaze following). In three phases of testing, we consistently found that the strongest relation was between chimpanzee g scores and efficiency in the HDT. Chimpanzee g was not most closely related to the proportion of trials the chimpanzees chose to try to wait for delayed rewards, but rather most closely related to how good they were at waiting for those rewards when they chose to do so. We also found the same strong relation between HDT efficiency and those factors in the PCTB that loaded most strongly on chimpanzee g. These results highlight that, as with humans, there is a strong relation between chimpanzees' self-control and overall intelligence-a relation that likely reflects the role of successful inhibitory control during cognitive processing of information and intelligent decision-making.
Topics: Animals; Choice Behavior; Female; Intelligence; Male; Pan troglodytes; Reward; Self-Control; Social Behavior
PubMed: 29429613
DOI: 10.1016/j.cub.2017.12.043