Long-term observational studies in a number of animal species suggest that exchange patterns of social acts depend on long-term emotional bonds. Therefore, it is expected that the frequency of ...prosocial behavior will depend on the strength of such a bond. In this study we tested whether variation in relationship quality among unrelated individuals, i.e., “friends” and “nonfriends,” is predictive of the prosocial behavior of long-tailed macaques in two experiments. First, we related relationship quality to prosociality in a dyadic prosociality test, and second, we gave subjects the choice to give to either a friend or a nonfriend in a triadic choice test. We show that prosocial behavior of long-tailed macaques in the dyadic test is not related to relationship quality. When given the choice to give to either a friend or a nonfriend in the triadic test, there is a minor indication that long-tailed macaques show a preference to give to their friends, yet this indication is neither significant nor consistent. In contrast, subordinate long-tailed macaques make a more “competitive” choice and avoid giving to the individual closest in rank. Therefore, in the short-term situation of experimental tests, prosocial behavior of long-tailed macaques seems unaffected by the relationship quality of the dyad/triad tested, and the relative dominance position of these dyads/triads seems to have a much stronger effect on their prosocial behavior.
Prosocial behaviour (i.e., voluntary behaviour intended to benefit another) seems to be fully developed in children by the age of 6 years. However, questions about which factors modify prosocial ...behaviour at that age remain understudied. Here we used a resource allocation paradigm to test prosocial behaviour in 6-9-year-old school children. They could decide between a "selfish" (i.e., one sticker for themselves) and a "prosocial" option (i.e., one sticker for themselves and one for the receiver) and we tested whether friendship, social status and prenatal androgen exposure (approximated by the 2nd to 4th digit ratio; 2D:4D) influenced children's prosocial choices. We found that children behaved prosocially, and that their prosocial tendencies were negatively correlated with prenatal androgen exposure; i.e., children with high 2D:4D ratios (reflecting low prenatal androgen exposure) acted more prosocially than children with low 2D:4D ratios. Further, their social status in the classroom influenced their choices: children with fewer interaction partners chose the "prosocial" option more often than more 'popular' children. However, they did so irrespectively of whether they were paired with a recipient or not. Our results highlight the importance of considering social, as well as physiological factors when investigating prosocial behaviour in children.
Many social species maintain differentiated relationships with their group members. These social bonds may reflect short-term interactions satisfying immediate needs. Alternatively, individuals of ...some species may entertain stable and valuable bonds that last much longer than opportunistic interactions would predict. This claim is supported by recent research that revealed clear fitness benefits for long-lasting social bonds. Here, we investigated the stability and equitability of social relationships in captive rhesus macaques, measured using their proximity and grooming patterns over a 3-yr period. We show that, in general, proximity patterns of the whole group were stable over 3 yr. More specifically, each individual’s top two nonkin within and between sex relationships based on proximity were relatively stable and some of these relationships lasted the full 3 yr. Female grooming relationships within and between sex were also stable over 3 yr. Moreover, strong social bonds in females were not based on age similarity and were not sex specific, suggesting that a general underlying mechanism of social bonding in female rhesus macaques. In contrast, patterns of male grooming of other males and of females were relatively unstable and male social bonds were less equitable than those of females. The differences in stability of the relationships between the sexes may reflect the dispersal pattern of rhesus macaques, although we have limited data on non-natal males in our study. With these data we add to a growing body of literature describing the value and durability of relationships among primates and other species.
Male mating success in a multimale–multifemale group can depend on several variables: body condition, dominance, coalitions, “friendship,” or an exchange of services for mating access. Exchange ...patterns may also be determined by market effects or social relationships. We studied the mating tactics of males in a captive, multimale–multifemale group of rhesus macaques and the resulting patterns of mating and paternity to determine the influence of dominance rank, mating markets, and relationship quality on their mating tactics. Male rank was positively related to the total number of copulations and the number of mating partners, but did not explain male mating distribution completely. Moreover, male fertilization success was not related to male rank. Males did not exchange grooming for mating access on the same day and neither the supply nor the rank (as a proxy for quality) of receptive females affected the amount of male grooming, suggesting that market effects did not explain male mating access. However, there was a positive correlation between long-term grooming patterns of both males and females and mating access, indicating that social relationships were important for male mating access. Paternity data revealed that these social relationships were also important for male reproductive success. We conclude that both male rank and male–female “friendship” determined male mating access in these rhesus macaques, but that “friendship” was more important in determining paternity, emphasizing the importance of intersex social bonds in male mating success in multimale primate societies.
Prosociality in a despotic society Bhattacharjee, Debottam; Cousin, Eythan; Pflüger, Lena S. ...
iScience,
05/2023, Letnik:
26, Številka:
5
Journal Article
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Prosociality is the intent to improve others’ well-being. Existing hypotheses postulate that enhanced social tolerance and inter-individual dependence may facilitate prosocial preferences, which may ...favor the evolution of altruism. While most studies are restricted to “tolerant” (cooperatively breeding and self-domesticated) species, despotic societies provide an alternative opportunity to investigate prosociality due to nepotism and ample inter-individual dependencies. Japanese macaques live in hierarchical matrilineal societies, with strong kin bonds. Besides, tolerance among non-kin may persist through reciprocity. Using a group service food-provision paradigm, we found prosocial preferences in a semi free-ranging group of Japanese macaques. The extent of provisioning was at levels comparable to tolerant species. Dyadic tolerance predicted the likelihood and magnitude of provisioning, while kinship predicted the magnitude. We emphasize the role of a complex socio-ecology fostering individual prosocial tendencies through kinship and tolerance. These findings necessitate a framework including different forms of interdependence beyond the generally tolerant species.
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•Conventionally, research on prosociality is restricted to tolerant societies•We show despotic semi free-ranging Japanese macaques have prosocial preferences too•Dyadic social tolerance and kinship positively predict prosocial provisioning•Selective prosocial preferences may be maintained by inter-individual dependencies
Biological sciences; Zoology; Evolutionary biology
The extent to which humans help each other is extraordinary in itself, and difficult to explain from an evolutionary perspective. Therefore, there has been a recent surge in studies investigating the ...evolution of prosocial behavior using a comparative approach. Nevertheless, most of these studies have focused on primates only, and little is known about other animal orders. In a previous study, common ravens (Corvus corax) have been shown to be indifferent to the gains of conspecifics. However, this may have been due to the experimental set-up, as many studies that use different set-ups report conflicting results within the same species. We therefore tested ravens' prosocial tendencies in a different set-up; i.e., we tested whether sub-adult ravens would transfer a token to a partner and, thereby, provide the partner with the opportunity to exchange a token for a reward. To control and test for effects of partner identity, we tested eight individuals both in a dyadic and in a group setting. Our results show that in general the ravens in our experiment did not show other-regarding preferences. However, some acts of helping did occur spontaneously. We discuss what could be the causes for those sporadic instances, and why in general prosocial tendencies were found to be almost lacking among the ravens in this set-up.
Social animals may employ evolved implicit rules to maintain a balance between cooperation and competition. Inequity aversion (IA), the aversive reaction to an unequal distribution of resources, is ...considered such a rule to avoid exploitation between cooperating individuals. Recent studies have revealed the presence of IA in several nonhuman species. In addition, it has been shown that an effort is crucial for this behavior to occur in animals. Moreover, IA may well depend on the partner's identity. Although dominant individuals typically monopolize food, subordinate individuals obtain less preferred food and usually do not protest. Furthermore, “friends” may pay less attention to equity than “nonfriends.” We tested whether long‐tailed macaques show IA with different cost–benefit ratios. In addition, we determined whether IA depends on relationship quality (RQ). Dominant subjects expressed IA only when a small effort was required. At a very large effort, however, long‐tailed macaques did not show IA, possibly owing to bottom effects on the number of rewards they aim to receive. Moreover, and contrary to our predictions, an individual's inequity response was similar when tested with a “friend” or a “nonfriend.” Therefore, we conclude that long‐tailed macaques show IA only in conditions of moderate effort, yet that IA seems independent of RQ. Furthermore, IA may not be domain specific. Altogether, IA may be a trait present in all species that habitually cooperate, independent of their social organization.
In recent years, there has been considerable research effort to determine whether other species exhibit prosocial motivations parallel to those of humans; however, these studies have focused ...primarily on primates, and with mixed results. We presented captive ravens with a modified prosocial choice task which aimed to address several criticisms of previous methods by including a stringent pretraining regime and a set-up that disentangles motivation to provision a conspecific from motivation to feed next to one. In this task six subjects received no rewards for themselves but could choose to deliver food rewards to either a conspecific or an empty, inaccessible compartment. Subjects did not demonstrate any prosocial tendencies (i.e. they did not preferentially choose to reward a conspecific over the empty compartment), and instead often ceased pulling on test trials when they received nothing for themselves (up to 70% of 80 trials with a partner present, up to 83% of 40 trials in a nonsocial control condition). The relationship between the subject and the partner had no influence on the subject's choices; however, subjects were more likely to pull immediately after performing socio-agonistic displays. Our results contribute to a growing body of evidence that despite their sophisticated social cognitive abilities and range of cooperative behaviours exhibited in the wild, unpaired (or unbonded) ravens do not seem to act to benefit conspecifics in the absence of immediate self-gain.
•Most studies of prosociality in nonhuman animals have focused on primates.•We examined whether ravens act to provide food to their group mates.•Ravens were not prosocial towards partners, regardless of their relationship.•Instead, subjects stopped responding on trials when they received no rewards.
The long-term effects of early adverse experiences on later psychosocial functioning are well described in humans, but sparsely documented for chimpanzees. In our earlier studies, we investigated the ...effects of maternal and social deprivation on three groups of ex-laboratory chimpanzees who experienced either an early or later onset of long-term deprivation. Here we expand our research by adding data on subjects that came from two stable zoo groups. The groups comprised of early maternally deprived wild-caught chimpanzees and non-deprived zoo-born chimpanzees. We found that compared to zoo chimpanzees, ex-laboratory chimpanzees were more restricted regarding their association partners in the newly formed groups, but not during their second year of group-life, indicating that social stability has an important influence on the toleration of association partners close-by. Social grooming activity, however, was impaired in early long-term deprived ex-laboratory chimpanzees as well as in early maternally deprived zoo chimpanzees compared to non-deprived zoo chimpanzees. Thus, we conclude that early maternal loss has lifelong effects on the social integration of chimpanzees which becomes evident in their grooming networks. Although the retrospective nature of our study prevents a clear causal explanation, our results are of importance for understanding the development of social competence in chimpanzees.
Behavioral contagion is suggested to promote group coordination that may facilitate activity transitions, increased vigilance, and state matching. Apart from contagious yawning, however, very little ...attention has been given to this phenomenon, and studies on contagious yawning in primates have so far only focused on Old World monkeys and apes. Here we studied behavioral contagion in common marmosets, a species for which group coordination and vigilance are paramount. In particular, we investigated the contagiousness of yawning, stretching, scratching, tongue protrusion, gnawing, and scent-marking. We coded these behaviors from 14 adult marmosets, from two different social groups. During testing sessions, animals were separated into groups of four individuals for 20-min observation periods, across three distinct diurnal time points (morning, midday, and afternoon) to test for circadian patterns. We observed almost no yawning (0.12 yawns/h) and very little stretching behavior. For all other behaviors, which were more common, we found several temporal and inter-individual differences (i.e., sex, age, dominance status) predictive of these responses. Moreover, we found that gnawing and scent-marking, which almost always co-occurred as a fixed-action pattern, were highly temporally clustered within observation sessions. We discuss the relative absence of yawning in marmosets as well as the possible function of contagious scent-marking, and provide suggestions for future research into the proximate and ultimate functions of these behaviors in marmosets.
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