Chimpanzees (Pan troglodytes) show subtle signs of uncertainty when choices are more difficult.
Ontology highlight
ABSTRACT:
SUBMITTER: Allritz M
PROVIDER: S-EPMC8346948 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Social risk is a domain of risk in which the costs, benefits, and uncertainty of an action depend on the behavior of another individual. Humans overvalue the costs of a socially risky decision when compared with that of purely economic risk. Here, we played a trust game with 8 female captive chimpanzees ( Pan troglodytes) to determine whether this bias exists in one of our closest living relatives. A correlation between an individual's social- and nonsocial-risk attitudes indicated stable individual variation, yet the chimpanzees were more averse to social than nonsocial risk. This indicates differences between social and economic decision making and emotional factors in social risk taking. In another experiment using the same paradigm, subjects played with several partners with whom they had varying relationships. Preexisting relationships did not impact the subjects' choices. Instead, the apes used a tit-for-tat strategy and were influenced by the outcome of early interactions with a partner.
| S-EPMC6794651 | biostudies-literature
Project description:The isolation effect (or von Restorff effect) occurs when one item in a to-be-remembered list is distinctive from all remaining items, and memory for that item is enhanced. Four chimpanzees were presented with a serial list of four photographs. In the homogeneous condition, all list items were from the same semantic category (e.g., four fruits). In the isolate condition, three items were from the same category, but the fourth item (the isolate) was from a different category (e.g., three fruits and one toy). Then, two photographs were presented, and the chimpanzees had to select the one that was from the list. Two of four chimpanzees were significantly more likely to select a correct isolate item than an item from the same list position in the homogeneous condition for at least some list positions. This facilitation in performance was for isolate items only, as presenting an isolate item in a list did not facilitate greater recognition of other list items compared to the homogeneous condition. These results indicated that some chimpanzees perceived the semantic categories of the photographs, and categorization of photographs led to the isolation effect. Thus, chimpanzees may share with humans some aspects of memory organization that involve spontaneously categorizing visual stimuli and recognizing categorically unique stimuli.
| S-EPMC3193283 | biostudies-literature
Project description:Bodies are important social cues for animals. Body recognition in humans is deteriorated by inversion. This inversion effect suggests the configural processing of bodies, which is different from the processing used for other objects. However, it is not known if this type of body processing exists in non-human primates. We tested seven chimpanzees using upright and inverted chimpanzee body stimuli and other stimuli in matching-to-sample tasks to examine the body inversion effect and the body parts that invoke it. Our results reflected the body inversion effect for intact chimpanzee bodies, bodies with complete body contours, and bodies with clear faces but not for the objects and other conditions that did not present complete body contours and clear faces. The results show that chimpanzees share configural body processing with humans and that bodies are special to them compared with other objects. The results also revealed the functions of faces and body contours in configural processing by chimpanzees.
| S-EPMC6169876 | biostudies-literature
Project description:Comparative thanatology encompasses the study of death-related responses in non-human animals and aspires to elucidate the evolutionary origins of human behavior in the context of death. Many reports have revealed that humans are not the only species affected by the death of group members. Non-human primates in particular show behaviors such as congregating around the deceased, carrying the corpse for prolonged periods of time (predominantly mothers carrying dead infants), and inspecting the corpse for signs of life. Here, we extend the focus on death-related responses in non-human animals by exploring whether chimpanzees are inclined to console the bereaved: the individual(s) most closely associated with the deceased. We report a case in which a chimpanzee (Pan troglodytes) mother experienced the loss of her fully developed infant (presumed stillborn). Using observational data to compare the group members' behavior before and after the death, we found that a substantial number of group members selectively increased their affiliative expressions toward the bereaved mother. Moreover, on the day of the death, we observed heightened expressions of species-typical reassurance behaviors toward the bereaved mother. After ruling out several alternative explanations, we propose that many of the chimpanzees consoled the bereaved mother by means of affiliative and selective empathetic expressions.
| S-EPMC6971188 | biostudies-literature
Project description:Chimpanzees (Pan troglodytes), one of humankinds' closest living relatives, are known to hunt and consume the meat of various animal taxa. Although some researchers have presented indirect evidence that chimpanzees may also prey on tortoises, until now, direct observations of this behaviour did not exist. Here, we provide systematic descriptions of the first observations of chimpanzee predation on tortoises (Kinixys erosa). We made these unprecedented observations on newly habituated chimpanzees (Pan troglodytes troglodytes) of the Rekambo community, living in the Loango National Park, Gabon. The behaviour qualified as customary, that is occurring in most or all adult males, involved a distinct smashing technique, and resulted frequently in food sharing with other group members. Our observations shed new light on the hitherto little understood percussive technology of chimpanzees, and expand our current knowledge on chimpanzees' dietary and predatory repertoires with respect to reptiles. We also report a case of food storage and discuss it in the context of future-oriented cognition. Our findings suggest the need for more nuanced interpretations of chimpanzees' cognitive skills in combination with an in-depth understanding of their unique socio-ecological niches. They further emphasize the importance of nonhuman primate field observations to inform theories of hominin evolution.
| S-EPMC6533303 | biostudies-literature
Project description:The face is quite an important stimulus category for human and nonhuman primates in their social lives. Recent advances in comparative-cognitive research clearly indicate that chimpanzees and humans process faces in a special manner; that is, using holistic or configural processing. Both species exhibit the face-inversion effect in which the inverted presentation of a face deteriorates their perception and recognition. Furthermore, recent studies have shown that humans detect human faces among non-facial objects rapidly. We report that chimpanzees detected chimpanzee faces among non-facial objects quite efficiently. This efficient search was not limited to own-species faces. They also found human adult and baby faces--but not monkey faces--efficiently. Additional testing showed that a front-view face was more readily detected than a profile, suggesting the important role of eye-to-eye contact. Chimpanzees also detected a photograph of a banana as efficiently as a face, but a further examination clearly indicated that the banana was detected mainly due to a low-level feature (i.e., color). Efficient face detection was hampered by an inverted presentation, suggesting that configural processing of faces is a critical element of efficient face detection in both species. This conclusion was supported by a simple simulation experiment using the saliency model.
| S-EPMC4504146 | biostudies-literature
Project description:Chimpanzees confer benefits on group members, both in the wild and in captive populations. Experimental studies of how animals allocate resources can provide useful insights about the motivations underlying prosocial behavior, and understanding the relationship between task design and prosocial behavior provides an important foundation for future research exploring these animals' social preferences. A number of studies have been designed to assess chimpanzees' preferences for outcomes that benefit others (prosocial preferences), but these studies vary greatly in both the results obtained and the methods used, and in most cases employ procedures that reduce critical features of naturalistic social interactions, such as partner choice. The focus of the current study is on understanding the link between experimental methodology and prosocial behavior in captive chimpanzees, rather than on describing these animals' social motivations themselves. We introduce a task design that avoids isolating subjects and allows them to freely decide whether to participate in the experiment. We explore key elements of the methods utilized in previous experiments in an effort to evaluate two possibilities that have been offered to explain why different experimental designs produce different results: (a) chimpanzees are less likely to deliver food to others when they obtain food for themselves, and (b) evidence of prosociality may be obscured by more "complex" experimental apparatuses (e.g., those including more components or alternative choices). Our results suggest that the complexity of laboratory tasks may generate observed variation in prosocial behavior in laboratory experiments, and highlights the need for more naturalistic research designs while also providing one example of such a paradigm.
| S-EPMC4156467 | biostudies-literature
Project description:Social learning is predicted to evolve in socially living animals provided the learning process is not random but biased by certain socio-ecological factors. One bias of particular interest for the emergence of (cumulative) culture is the tendency to forgo personal behaviour in favour of relatively better variants observed in others, also known as the "copy-if-better" strategy. We investigated whether chimpanzees employ copy-if-better in a simple token-exchange paradigm controlling for individual and random social learning. After being trained on one token-type, subjects were confronted with a conspecific demonstrator who either received the same food reward as the subject (control condition) or a higher value food reward than the subject (test condition) for exchanging another token-type. In general, the chimpanzees persisted in exchanging the token-type they were trained on individually, indicating a form of conservatism consistent with previous studies. However, the chimpanzees were more inclined to copy the demonstrator in the test compared to the control condition, indicating a tendency to employ a copy-if-better strategy. We discuss the validity of our results by considering alternative explanations and relate our findings to the emergence of cumulative culture.
| S-EPMC5394136 | biostudies-literature
Project description:Despite their genetic similarity to humans, our understanding of the role of genes on cognitive traits in chimpanzees remains virtually unexplored. Here, we examined the relationship between genetic variation in the arginine vasopressin V1a receptor gene (AVPR1A) and social cognition in chimpanzees. Studies have shown that chimpanzees are polymorphic for a deletion in a sequence in the 5' flanking region of the AVPR1A, DupB, which contains the variable RS3 repetitive element, which has been associated with variation in social behavior in humans. Results revealed that performance on the social cognition task was significantly heritable. Furthermore, males with one DupB(+) allele performed significantly better and were more responsive to socio-communicative cues than males homozygous for the DupB- deletion. Performance on a non-social cognition task was not associated with the AVPR1A genotype. The collective findings show that AVPR1A polymorphisms are associated with individual differences in performance on a receptive joint attention task in chimpanzees.
| S-EPMC3895903 | biostudies-other
Project description:Ranging behavior has been studied extensively in eastern (Pan troglodytes schweinfurthii) and western (P. t. verus) chimpanzees, but relatively little is known regarding home ranges of the other two subspecies (P. t. ellioti; P. t. troglodytes). In this study, we determined the home range size and space use of a habituated community (Rekambo) of central chimpanzees living in a habitat mosaic in Loango National Park, Gabon. Data on travel routes were collected during follows between January 2017 and April 2019 (N = 670,616 relocations, collected over 640 days and 5690 h of observation). We used three methods for calculating home range size (minimum convex polygon, kernel density estimation, and biased random bridges). We compare our estimates to those obtained from prior genetic and camera trap studies of the Rekambo community and contrast them with estimates from other chimpanzee communities of the four chimpanzee subspecies. Depending on the methodology used, the home range size of the Rekambo community ranged between 27.64 and 59.03 km2. The location of the center of the home range remained relatively stable over the last decade, while the overall size decreased. The Rekambo home range is, therefore, one of the largest documented so far for chimpanzees outside savannah-woodland habitats. We discuss several explanations, including the presence of savannah, interspecies competition, and intercommunity interactions.
| S-EPMC8410711 | biostudies-literature