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Evolutionary Anthropology Nov 2018Property is a key feature of modern human society; however, identifying the origin of this multifaceted behavior poses a formidable challenge. Here, we explore the... (Review)
Review
Property is a key feature of modern human society; however, identifying the origin of this multifaceted behavior poses a formidable challenge. Here, we explore the methodologies for researching the origin of property. We discuss how an interdisciplinary approach can shed light on how our human ancestors shifted behaviorally from possessing an object to having exclusive property control over it. Possession occurs when social group members only respect an individual's claim to have exclusive access to an object when the individual has physical control over the object. Property occurs when an individual can claim exclusive access to an object, without challenge, regardless of whether the object is in their physical control or not. Researchers across different disciplines have asked what, if anything, distinguishes human property behavior from the behavior of other animals? Further, when and how did this behavior evolve in our lineage? Due to the considerable methodological challenges posed by researching this topic, few studies have been able to directly address these questions. In this review, we explore the challenges involved in defining property and possession and suggest a two-step approach to interdisciplinary definitions. Next, we evaluate four core approaches to the study of property behavior: evolutionary game theory, ethology, comparative cognition, and developmental psychology. Finally, we propose an empirical study, using an ethological approach to test the presence of property and possessive behavior in a natural setting, using our closest living relative, the chimpanzee (Pan troglodytes). Overall, we argue that this field of research is at a turning point, where the novel integration of various methods may provide an explanation to the origin of property.
Topics: Animals; Anthropology, Physical; Behavior, Animal; Biological Evolution; Ethology; Models, Biological; Ownership; Pan troglodytes
PubMed: 30290031
DOI: 10.1002/evan.21748 -
Proceedings. Biological Sciences Apr 2022In zoos, primates experience markedly different interactions with familiar humans, such as the zookeepers who care for them, compared with those with unfamiliar humans,...
In zoos, primates experience markedly different interactions with familiar humans, such as the zookeepers who care for them, compared with those with unfamiliar humans, such as the large volume of zoo visitors to whom they are regularly exposed. While the behaviour of zoo-housed primates in the presence of unfamiliar, and to a lesser extent familiar, humans has received considerable attention, if and how they spontaneously distinguish familiar from unfamiliar people, and the cognitive mechanisms underlying the relationships they form with familiar and unfamiliar humans, remain poorly understood. Using a dot-probe paradigm, we assessed whether primates (chimpanzees and gorillas) show an attentional bias toward the faces of familiar humans, with whom the apes presumably had a positive relationship. Contrary to our predictions, all subjects showed a significant attentional bias toward unfamiliar people's faces compared with familiar people's faces when the faces showed a neutral expression, both with and without a surgical face mask on, but no significant attentional bias when the faces showed a surprised expression. These results demonstrate that apes can spontaneously categorize humans based on familiarity and we argue that the attentional biases the apes showed for unfamiliar human faces reflect a novelty effect.
Topics: Animals; Attention; Attentional Bias; Hominidae; Humans; Pan troglodytes; Recognition, Psychology
PubMed: 35473378
DOI: 10.1098/rspb.2021.2599 -
American Journal of Primatology Feb 2022Chimpanzees (Pan troglodytes) have a complex mating system in which both sexes use multiple tactics. Most copulations occur in group contexts, and high-ranking males can...
Chimpanzees (Pan troglodytes) have a complex mating system in which both sexes use multiple tactics. Most copulations occur in group contexts, and high-ranking males can gain high mating and reproductive success, but females typically mate with multiple males and the potential for sperm competition is high. Also, male-female dyads sometimes form temporary exclusive mating associations (consortships). Male aggression to receptive females is common. Several studies have supported the hypothesis that this is sexual coercion, but debate exists regarding the importance of coercion relative to that of female choice. The number of adult males in a community can influence the balance between these processes. In the large Ngogo community, male dominance ranks and rates of aggression to fully-swollen females were positively related to mating success as estimated by copulation rates and by proportions of copulations achieved. Aggression rates were higher than at other sites, overall and per male, especially during periovulatory periods, and increased with the number of males associating with a female. Aggression impaired female foraging efficiency. Males initiated most copulations and females rarely refused mating attempts. Male-to-female grooming was positively associated with male mating success and with the proportion of copulations that females initiated, but the amount of grooming was typically small and whether grooming-for-mating trading occurs is uncertain. These results are consistent with the hypothesis that sexual coercion is an important component of male chimpanzee mating strategies in many sociodemographic circumstances, but also show that male tactics vary both in response to and independently of those circumstances.
Topics: Animals; Coercion; Copulation; Female; Male; Pan troglodytes; Reproduction; Sexual Behavior, Animal
PubMed: 35029301
DOI: 10.1002/ajp.23361 -
Heredity Aug 2020Populations of the common chimpanzee (Pan troglodytes) are in an impending risk of going extinct in the wild as a consequence of damaging anthropogenic impact on their...
Populations of the common chimpanzee (Pan troglodytes) are in an impending risk of going extinct in the wild as a consequence of damaging anthropogenic impact on their natural habitat and illegal pet and bushmeat trade. Conservation management programmes for the chimpanzee have been established outside their natural range (ex situ), and chimpanzees from these programmes could potentially be used to supplement future conservation initiatives in the wild (in situ). However, these programmes have often suffered from inadequate information about the geographical origin and subspecies ancestry of the founders. Here, we present a newly designed capture array with ~60,000 ancestry informative markers used to infer ancestry of individual chimpanzees in ex situ populations and determine geographical origin of confiscated sanctuary individuals. From a test panel of 167 chimpanzees with unknown origins or subspecies labels, we identify 90 suitable non-admixed individuals in the European Association of Zoos and Aquaria (EAZA) Ex situ Programme (EEP). Equally important, another 46 individuals have been identified with admixed subspecies ancestries, which therefore over time, should be naturally phased out of the breeding populations. With potential for future re-introduction to the wild, we determine the geographical origin of 31 individuals that were confiscated from the illegal trade and demonstrate the promises of using non-invasive sampling in future conservation action plans. Collectively, our genomic approach provides an exemplar for ex situ management of endangered species and offers an efficient tool in future in situ efforts to combat the illegal wildlife trade.
Topics: Animals; Conservation of Natural Resources; Ecosystem; Endangered Species; Pan troglodytes
PubMed: 32346130
DOI: 10.1038/s41437-020-0313-0 -
Primates; Journal of Primatology Mar 2021In a captive environment, it is challenging to ensure the highest level of social and psychological well-being for species with naturally complex social organizations...
In a captive environment, it is challenging to ensure the highest level of social and psychological well-being for species with naturally complex social organizations and structures. There is a growing need to meet the social requirements for individuals of these species, especially chimpanzees, housed in zoos, sanctuaries, rehabilitation centers, and laboratories. Complex social interactions and broader social structures can be aptly described via social network analysis. We expand on the literature regarding captive chimpanzee social networks, but uniquely consider their human caregivers as potential social partners. We observed the social interactions between one group of seven chimpanzees (Pan troglodytes) and their caregivers in six behavioral contexts (nearest neighbor, play, aggression, grooming, grooming solicitation, and social vigilance) at Chimpanzee Sanctuary Northwest (USA). By constructing multiple chimpanzee and chimpanzee-caregiver social networks, our results indicate that caregivers are integrated partners in this group's social structure. Additionally, we observed that the type and strength of chimpanzee-caregiver relationships varied between the chimpanzees. These results support the notion that caregivers offer additional opportunities (i.e., beyond those with conspecifics) for captive chimpanzees to construct and maintain meaningful social relationships. Our results show that considerations of captive primate social dynamics should include caregivers as potentially important social partners. Our results also highlight the importance of evaluating individual chimpanzee characteristics when developing philosophies of care and adopting husbandry practices that offer fulfilling social niches. Our findings bear influence on contemporary discussions of interspecies social relationships, captive welfare, health, translocation, and husbandry protocols for captive chimpanzees and other nonhuman primates.
Topics: Animal Husbandry; Animal Welfare; Animals; Behavior, Animal; Female; Human-Animal Interaction; Humans; Male; Pan troglodytes; Social Behavior
PubMed: 33034790
DOI: 10.1007/s10329-020-00867-6 -
Neuroscience and Biobehavioral Reviews Mar 2022In this article we review publications relevant to addressing widely reported claims in both the academic and popular press that chimpanzees working memory (WM) is... (Review)
Review
In this article we review publications relevant to addressing widely reported claims in both the academic and popular press that chimpanzees working memory (WM) is comparable to, if not exceeding, that of humans. WM is a complex multidimensional construct with strong parallels in humans to prefrontal cortex and cognitive development. These parallels occur in chimpanzees, but to a lesser degree. We review empirical evidence and conclude that the size of WM in chimpanzees is 2 ± 1 versus Miller's famous 7 ± 2 in humans. Comparable differences occur in experiments on chimpanzees relating to strategic and attentional WM subsystems. Regardless of the domain, chimpanzee WM performance is comparable to that of humans around the age of 4 or 5. Next, we review evidence showing parallels among the evolution of WM capacity in hominins ancestral to Homo sapiens, the phylogenetic evolution of hominins leading to Homo sapiens, and evolution in the complexity of stone tool technology over this time period.
Topics: Animals; Biological Evolution; Hominidae; Humans; Memory, Short-Term; Pan troglodytes; Phylogeny
PubMed: 34919985
DOI: 10.1016/j.neubiorev.2021.12.019 -
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 -
Anatomical Record (Hoboken, N.J. : 2007) May 2017Elucidating the pelvic morphology of the Pan-Homo last common ancestor (LCA) is crucial for understanding ape and human evolution. The pelvis of Ardipithecus ramidus has...
Elucidating the pelvic morphology of the Pan-Homo last common ancestor (LCA) is crucial for understanding ape and human evolution. The pelvis of Ardipithecus ramidus has been the basis of controversial interpretations of the LCA pelvis. In particular, it was proposed that the lower ilium became elongate independently in the orangutan and chimpanzee clades, making these taxa poor analogues for the pelvis of the LCA. This study examines the variation in relative lower ilium height between and within living and fossil hominoid species (and other anthropoids), and models its evolution using available fossil hominoids as calibration points. We find nuanced differences in relative lower ilium height among living hominoids, particularly in regards to gorillas, which do not have elongate lower ilia (because they are likely to represent the plesiomorphic hominoid condition for this trait). We also show that differences in relative lower ilium height among hominoid taxa are not readily explained by differences in size between species. Our maximum likelihood ancestral state reconstructions support inferences that chimpanzees (Pan troglodytes in particular) and orangutans evolved their elongate lower ilia independently. We also find that the predicted lower ilium height of the Pan-Homo LCA is shorter than all great apes except gorillas. This study adds to a growing body of evidence that finds different regions of the body show different evolutionary histories in different hominoids, and underscores that the unique combinations of morphologies of each modern and fossil hominoid species should be considered when reconstructing the mosaic nature of the Pan-Homo LCA. Anat Rec, 300:828-844, 2017. © 2017 Wiley Periodicals, Inc.
Topics: Animals; Biological Evolution; Fossils; Hominidae; Ilium; Pan troglodytes; Phylogeny
PubMed: 28406561
DOI: 10.1002/ar.23545 -
Journal of Comparative Psychology... Aug 2020Eye gaze is widespread in nonhuman primate taxa and important for social cognition and communicative signaling. Bonobos and chimpanzees, two closely related primate...
Eye gaze is widespread in nonhuman primate taxa and important for social cognition and communicative signaling. Bonobos and chimpanzees, two closely related primate species, differ in social organization, behavior, and cognition. Chimpanzees' eye gaze and gaze following has been studied extensively, whereas less is known about bonobos' eye gaze. To examine species differences using a more ecologically relevant measure than videos or pictures, the current study compared bonobo and chimpanzee mutual eye gaze with a human observer. A multivariate analysis of variance revealed significant species differences in frequency and total duration, but not bout length, of mutual eye gaze ( < .001). Specifically, bonobos engage in mutual eye gaze more frequently and for longer total duration than chimpanzees. These results are likely related to species differences in social behavior and temperament and are consistent with eye-tracking studies in which bonobos looked at the eye region of conspecifics (in pictures and videos) longer than chimpanzees. Future research should examine the relationship between mutual eye gaze and gaze following, as well as examine its genetic and neurological correlates. (PsycInfo Database Record (c) 2020 APA, all rights reserved).
Topics: Animals; Behavior, Animal; Female; Fixation, Ocular; Humans; Pan paniscus; Pan troglodytes; Social Behavior; Species Specificity
PubMed: 32804530
DOI: 10.1037/com0000247