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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 -
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 -
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 -
Proceedings of the National Academy of... Feb 2013Is the sense of fairness uniquely human? Human reactions to reward division are often studied by means of the ultimatum game, in which both partners need to agree on a...
Is the sense of fairness uniquely human? Human reactions to reward division are often studied by means of the ultimatum game, in which both partners need to agree on a distribution for both to receive rewards. Humans typically offer generous portions of the reward to their partner, a tendency our close primate relatives have thus far failed to show in experiments. Here we tested chimpanzees (Pan troglodytes) and human children on a modified ultimatum game. One individual chose between two tokens that, with their partner's cooperation, could be exchanged for rewards. One token offered equal rewards to both players, whereas the other token favored the chooser. Both apes and children responded like humans typically do. If their partner's cooperation was required, they split the rewards equally. However, with passive partners--a situation akin to the so-called dictator game--they preferred the selfish option. Thus, humans and chimpanzees show similar preferences regarding reward division, suggesting a long evolutionary history to the human sense of fairness.
Topics: Animals; Biological Evolution; Child; Choice Behavior; Cooperative Behavior; Game Theory; Humans; Pan troglodytes; Play and Playthings; Reward; Social Behavior
PubMed: 23319633
DOI: 10.1073/pnas.1220806110 -
Scientific Reports Jul 2018In wild animal conservation, knowing the age of an individual animal is extremely beneficial. However, estimating the age is difficult for many species. Recently,...
In wild animal conservation, knowing the age of an individual animal is extremely beneficial. However, estimating the age is difficult for many species. Recently, epigenetics-based methods of estimating age have been reported. These studies were predominantly on humans with few reports on other animals, especially wild animals. In the present study, a chimpanzee (Pan troglodytes) age prediction model was developed based on the ELOVL2, CCDC102B, and ZNF423 genes that may also have application in human age prediction. Pyrosequencing was used to measure methylation in 20 chimpanzee blood samples and correlation between age and methylation status was calculated. Age and methylation of sites in ELOVL2 and CCDC102B were significantly correlated and an age prediction model was created using these genes. In the regression equation using only ELOVL2, the highest correlation coefficient was 0.741, with a mean absolute deviation (MAD) of 5.41, compared with the combination of ELOVL2 and CCDC102B, where the highest correlation coefficient was 0.742 and the MAD was 5.41. Although larger MADs were observed in chimpanzees than in humans based on these genes, the results indicate the feasibility of estimating chimpanzee age using DNA methylation, and can have implications in understanding the ecology of chimpanzees and chimpanzee conservation.
Topics: Age Factors; Animals; CpG Islands; DNA Methylation; Epigenesis, Genetic; Epigenomics; Forecasting; Forensic Genetics; Pan troglodytes; Sequence Analysis, DNA
PubMed: 29968770
DOI: 10.1038/s41598-018-28318-9 -
Proceedings of the National Academy of... Dec 2014
Topics: Animals; Animals, Wild; Behavior, Animal; Female; Male; Pan troglodytes; Social Behavior
PubMed: 25512536
DOI: 10.1073/pnas.1421559112