Bonobos respond prosocially toward members of other groups
https://www.nature.com/articles/s41598-017-15320-w
>Modern humans live in an “exploded” network with unusually large circles of trust that form due to prosociality toward unfamiliar people (i.e. xenophilia). In a set of experiments we demonstrate that semi-free ranging bonobos (Pan paniscus) – both juveniles and young adults – also show spontaneous responses consistent with xenophilia. Bonobos voluntarily aided an unfamiliar, non-group member in obtaining food even when he/she did not make overt requests for help. Bonobos also showed evidence for involuntary, contagious yawning in response to videos of yawning conspecifics who were complete strangers. These experiments reveal that xenophilia in bonobos can be unselfish, proactive and automatic. They support the first impression hypothesis that suggests xenophilia can evolve through individual selection in social species whenever the benefits of building new bonds outweigh the costs. Xenophilia likely evolved in bonobos as the risk of intergroup aggression dissipated and the benefits of bonding between immigrating members increased. Our findings also mean the human potential for xenophilia is either evolutionarily shared or convergent with bonobos and not unique to our species as previously proposed.
Bonobos Share with Strangers
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0051922
>Humans are thought to possess a unique proclivity to share with others – including strangers. This puzzling phenomenon has led many to suggest that sharing with strangers originates from human-unique language, social norms, warfare and/or cooperative breeding. However, bonobos, our closest living relative, are highly tolerant and, in the wild, are capable of having affiliative interactions with strangers. In four experiments, we therefore examined whether bonobos will voluntarily donate food to strangers. We show that bonobos will forego their own food for the benefit of interacting with a stranger. Their prosociality is in part driven by unselfish motivation, because bonobos will even help strangers acquire out-of-reach food when no desirable social interaction is possible. However, this prosociality has its limitations because bonobos will not donate food in their possession when a social interaction is not possible. These results indicate that other-regarding preferences toward strangers are not uniquely human. Moreover, language, social norms, warfare and cooperative breeding are unnecessary for the evolution of xenophilic sharing. Instead, we propose that prosociality toward strangers initially evolves due to selection for social tolerance, allowing the expansion of individual social networks. Human social norms and language may subsequently extend this ape-like social preference to the most costly contexts.
Bonobos Respond to Distress in Others: Consolation across the Age Spectrum
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0055206
>How animals respond to conflict provides key insights into the evolution of socio-cognitive and emotional capacities. Evidence from apes has shown that, after social conflicts, bystanders approach victims of aggression to offer stress-alleviating contact behavior, a phenomenon known as consolation. This other-orientated behavior depends on sensitivity to the other's emotional state, whereby the consoler acts to ameliorate the other's situation. We examined post-conflict interactions in bonobos (Pan paniscus) to identify the determinants of consolation and reconciliation. Thirty-six semi-free bonobos of all ages were observed at the Lola ya Bonobo Sanctuary, DR Congo, using standardized Post-conflict/Matched Control methods. Across age and sex classes, bonobos consoled victims and reconciled after conflicts using a suite of affiliative and socio-sexual behaviors including embracing, touching, and mounting. Juveniles were more likely to console than adults, challenging the assumption that comfort-giving rests on advanced cognitive mechanisms that emerge only with age. Mother-reared individuals were more likely to console than orphans, highlighting the role of rearing in emotional development. Consistent with previous studies, bystanders were more likely to console relatives or closely bonded partners. Effects of kinship, affiliation and rearing were similarly indicated in patterns of reconciliation. Nearby bystanders were significantly more likely to contact victims than more distal ones, and consolation was more likely in non-food contexts than during feeding. The results did not provide convincing evidence that bystander contacts served for self-protection or as substitutes for reconciliation. Overall, results indicate that a suite of social, developmental and contextual factors underlie consolation and reconciliation in bonobos and that a sensitivity to the emotions of others and the ability to provide appropriate consolatory behaviors emerges early in development.
Bonobos (Pan paniscus) show an attentional bias toward conspecifics’ emotions
http://www.pnas.org/content/113/14/3761
>Applying well-established psychological paradigms to our closest relatives represents a promising approach for providing insight into similarities and differences between humans and apes. Numerous articles have been published on the dot-probe task, showing that humans have an attentional bias toward emotions, especially when threatening. For social species like primates, efficiently responding to others’ emotions has great survival value. Observational research has shown that, compared with humans and chimpanzees, bonobos excel in regulating their own and others’ emotions, thereby preventing conflicts from escalating. The present study is an initial effort to apply a psychological test to the bonobo, and demonstrates that they, like humans, have heightened attention to emotional—compared with neutral—conspecifics, but are mostly drawn toward protective and affiliative emotions.
>In social animals, the fast detection of group members’ emotional expressions promotes swift and adequate responses, which is crucial for the maintenance of social bonds and ultimately for group survival. The dot-probe task is a well-established paradigm in psychology, measuring emotional attention through reaction times. Humans tend to be biased toward emotional images, especially when the emotion is of a threatening nature. Bonobos have rich, social emotional lives and are known for their soft and friendly character. In the present study, we investigated (i) whether bonobos, similar to humans, have an attentional bias toward emotional scenes compared with conspecifics showing a neutral expression, and (ii) which emotional behaviors attract their attention the most. As predicted, results consistently showed that bonobos’ attention was biased toward the location of the emotional versus neutral scene. Interestingly, their attention was grabbed most by images showing conspecifics such as sexual behavior, yawning, or grooming, and not as much—as is often observed in humans—by signs of distress or aggression. The results suggest that protective and affiliative behaviors are pivotal in bonobo society and therefore attract immediate attention in this species.
Bonobos help strangers without being asked
https://today.duke.edu/2017/11/bonobos-help-strangers-without-being-asked
>In one experiment, they found that bonobos will help a stranger get food even when there is no immediate payback.
Sixteen bonobos were led one at a time into one of two adjacent rooms separated by a fence. The researchers hung a piece of apple from a rope just above the empty room, visible but out of reach. The apes couldn’t access the fruit or the rope. But if they climbed the fence they could reach a wooden pin holding the rope to the ceiling and release the dangling fruit, causing it to drop within reach of any bonobo that entered the next room. The bonobos released the fruit roughly four times more often when an unfamiliar bonobo was in the adjacent room than when the room was empty.
>What’s more, the bonobos didn’t wait to be asked for help, they just offered it. The researchers changed the size of the mesh surrounding the stranger’s room so that in some trials they were able to stick their arms through the openings in the screen to beg for the treat, and in other trials they were not. The bonobos helped just as often whether the stranger gestured for help or not.
>Bonobos’ impulse to feel for strangers isn’t entirely under conscious control, the researchers also found. In another experiment, they had 21 bonobos watch a series of short videos. In some videos, the apes saw a familiar group member either yawning or making a neutral expression. In other videos they watched complete strangers from the Columbus Zoo in the U.S. behaving the same way.
>Just as watching another person yawn can make you yawn, yawning is contagious in bonobos too. Previous studies suggest the phenomenon is linked to a basic form of empathy called “emotional contagion,” when one person’s mood triggers similar emotions in others around them.
>The researchers found that stranger yawns were just as contagious as those of groupmates.
https://www.nature.com/articles/s41598-017-15320-w
>Modern humans live in an “exploded” network with unusually large circles of trust that form due to prosociality toward unfamiliar people (i.e. xenophilia). In a set of experiments we demonstrate that semi-free ranging bonobos (Pan paniscus) – both juveniles and young adults – also show spontaneous responses consistent with xenophilia. Bonobos voluntarily aided an unfamiliar, non-group member in obtaining food even when he/she did not make overt requests for help. Bonobos also showed evidence for involuntary, contagious yawning in response to videos of yawning conspecifics who were complete strangers. These experiments reveal that xenophilia in bonobos can be unselfish, proactive and automatic. They support the first impression hypothesis that suggests xenophilia can evolve through individual selection in social species whenever the benefits of building new bonds outweigh the costs. Xenophilia likely evolved in bonobos as the risk of intergroup aggression dissipated and the benefits of bonding between immigrating members increased. Our findings also mean the human potential for xenophilia is either evolutionarily shared or convergent with bonobos and not unique to our species as previously proposed.
Bonobos Share with Strangers
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0051922
>Humans are thought to possess a unique proclivity to share with others – including strangers. This puzzling phenomenon has led many to suggest that sharing with strangers originates from human-unique language, social norms, warfare and/or cooperative breeding. However, bonobos, our closest living relative, are highly tolerant and, in the wild, are capable of having affiliative interactions with strangers. In four experiments, we therefore examined whether bonobos will voluntarily donate food to strangers. We show that bonobos will forego their own food for the benefit of interacting with a stranger. Their prosociality is in part driven by unselfish motivation, because bonobos will even help strangers acquire out-of-reach food when no desirable social interaction is possible. However, this prosociality has its limitations because bonobos will not donate food in their possession when a social interaction is not possible. These results indicate that other-regarding preferences toward strangers are not uniquely human. Moreover, language, social norms, warfare and cooperative breeding are unnecessary for the evolution of xenophilic sharing. Instead, we propose that prosociality toward strangers initially evolves due to selection for social tolerance, allowing the expansion of individual social networks. Human social norms and language may subsequently extend this ape-like social preference to the most costly contexts.
Bonobos Respond to Distress in Others: Consolation across the Age Spectrum
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0055206
>How animals respond to conflict provides key insights into the evolution of socio-cognitive and emotional capacities. Evidence from apes has shown that, after social conflicts, bystanders approach victims of aggression to offer stress-alleviating contact behavior, a phenomenon known as consolation. This other-orientated behavior depends on sensitivity to the other's emotional state, whereby the consoler acts to ameliorate the other's situation. We examined post-conflict interactions in bonobos (Pan paniscus) to identify the determinants of consolation and reconciliation. Thirty-six semi-free bonobos of all ages were observed at the Lola ya Bonobo Sanctuary, DR Congo, using standardized Post-conflict/Matched Control methods. Across age and sex classes, bonobos consoled victims and reconciled after conflicts using a suite of affiliative and socio-sexual behaviors including embracing, touching, and mounting. Juveniles were more likely to console than adults, challenging the assumption that comfort-giving rests on advanced cognitive mechanisms that emerge only with age. Mother-reared individuals were more likely to console than orphans, highlighting the role of rearing in emotional development. Consistent with previous studies, bystanders were more likely to console relatives or closely bonded partners. Effects of kinship, affiliation and rearing were similarly indicated in patterns of reconciliation. Nearby bystanders were significantly more likely to contact victims than more distal ones, and consolation was more likely in non-food contexts than during feeding. The results did not provide convincing evidence that bystander contacts served for self-protection or as substitutes for reconciliation. Overall, results indicate that a suite of social, developmental and contextual factors underlie consolation and reconciliation in bonobos and that a sensitivity to the emotions of others and the ability to provide appropriate consolatory behaviors emerges early in development.
Bonobos (Pan paniscus) show an attentional bias toward conspecifics’ emotions
http://www.pnas.org/content/113/14/3761
>Applying well-established psychological paradigms to our closest relatives represents a promising approach for providing insight into similarities and differences between humans and apes. Numerous articles have been published on the dot-probe task, showing that humans have an attentional bias toward emotions, especially when threatening. For social species like primates, efficiently responding to others’ emotions has great survival value. Observational research has shown that, compared with humans and chimpanzees, bonobos excel in regulating their own and others’ emotions, thereby preventing conflicts from escalating. The present study is an initial effort to apply a psychological test to the bonobo, and demonstrates that they, like humans, have heightened attention to emotional—compared with neutral—conspecifics, but are mostly drawn toward protective and affiliative emotions.
>In social animals, the fast detection of group members’ emotional expressions promotes swift and adequate responses, which is crucial for the maintenance of social bonds and ultimately for group survival. The dot-probe task is a well-established paradigm in psychology, measuring emotional attention through reaction times. Humans tend to be biased toward emotional images, especially when the emotion is of a threatening nature. Bonobos have rich, social emotional lives and are known for their soft and friendly character. In the present study, we investigated (i) whether bonobos, similar to humans, have an attentional bias toward emotional scenes compared with conspecifics showing a neutral expression, and (ii) which emotional behaviors attract their attention the most. As predicted, results consistently showed that bonobos’ attention was biased toward the location of the emotional versus neutral scene. Interestingly, their attention was grabbed most by images showing conspecifics such as sexual behavior, yawning, or grooming, and not as much—as is often observed in humans—by signs of distress or aggression. The results suggest that protective and affiliative behaviors are pivotal in bonobo society and therefore attract immediate attention in this species.
Bonobos help strangers without being asked
https://today.duke.edu/2017/11/bonobos-help-strangers-without-being-asked
>In one experiment, they found that bonobos will help a stranger get food even when there is no immediate payback.
Sixteen bonobos were led one at a time into one of two adjacent rooms separated by a fence. The researchers hung a piece of apple from a rope just above the empty room, visible but out of reach. The apes couldn’t access the fruit or the rope. But if they climbed the fence they could reach a wooden pin holding the rope to the ceiling and release the dangling fruit, causing it to drop within reach of any bonobo that entered the next room. The bonobos released the fruit roughly four times more often when an unfamiliar bonobo was in the adjacent room than when the room was empty.
>What’s more, the bonobos didn’t wait to be asked for help, they just offered it. The researchers changed the size of the mesh surrounding the stranger’s room so that in some trials they were able to stick their arms through the openings in the screen to beg for the treat, and in other trials they were not. The bonobos helped just as often whether the stranger gestured for help or not.
>Bonobos’ impulse to feel for strangers isn’t entirely under conscious control, the researchers also found. In another experiment, they had 21 bonobos watch a series of short videos. In some videos, the apes saw a familiar group member either yawning or making a neutral expression. In other videos they watched complete strangers from the Columbus Zoo in the U.S. behaving the same way.
>Just as watching another person yawn can make you yawn, yawning is contagious in bonobos too. Previous studies suggest the phenomenon is linked to a basic form of empathy called “emotional contagion,” when one person’s mood triggers similar emotions in others around them.
>The researchers found that stranger yawns were just as contagious as those of groupmates.
