Appendix 2

Informative Cousins:
A Case Study

MMW Staff

Page Outline

1. Introduction
2. Group Living
3. Reconciliation
4. The Human Picture

Introduction

We are both closely and distantly related to chimpanzees and the very similar bonobos: closely in that they are the living animals most closely genetically similar to us, distantly in that the Last Common Ancestor is lost in the mists of time. It is therefore sometimes instructive and at times misleading to look at chimp anatomy or behavior, compare it with our own, and try to figure out whether what we share may (or may not!) represent our shared genetic heritage.

The temptation to compare ourselves with chimps is always more compelling in studying behavior than in studying anatomy. We have lots of bones from earlier hominoids. And we have some artifacts. We have no behaviors.

In this essay, we examine a specific experiment related to the phenomenon of reconciliation.

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Group Living

Primates are very social mammals, and they generally solve their adaptive problems through social means. Group-living and sociality in primates evolved as a response to ecological and/or predation pressures, particularly for females. The main benefits of group-living are protection from predation, defense of resources, and ready access to mates.

But there are also costs to group-living, including aggressive competition over resources, including food and mates. Since the primate adaptation is primarily social, maintaining the integrity of the social group is essential for primate survival. This means that some mechanism for coping with the costs of conflict is necessary. Primates, like other social mammals, have evolved mechanisms to reconcile conflict and repair damage done to relationships.

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Reconciliation

The primary means by which primates cope with conflict in their social groups is through reconciliation. Reconciliation is friendly contact with a former opponent shortly after the end of a conflict.

Frans de Waal, a primatologist at Emory University and the Yerkes National Primate Center, began studying reconciliation behavior in chimpanzees in the late 1970’s and has become one of the world’s leading experts in conflict management in non-human primates. In his first study of reconciliation in 1979, de Waal and his colleague Angeline van Roosmalen demonstrated that, contrary to popular belief at the time, former opponents did not avoid one another for very long after a fight. In fact, after a fight the chimpanzees often came back together within a few minutes to groom each other. (Grooming is the social cement of many primate relationships, somewhat like hugging and talking in humans.)

De Waal and van Roosmalen also reported some other very interesting results. They found that of the conflicts that were followed by reconciliation, most were between individuals with strong or valuable relationships. That is, individuals were more likely to reconcile conflicts with friends than with other individuals in the group.

De Waal and van Roosmalen also reported that after some conflicts, individuals sought friendly interactions with third-parties, individuals who were not involved in the conflict, and they called this consolation. As already noted, grooming was a very important behavior in reconciliation, but it was not the only one. Individuals also embraced and did mouth to mouth contact (“kissing”).

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The Human Picture

One of the most important similarities between chimps and humans turns out to be the importance of physical contact in reconciliation. After conflicts we are often agitated and feel somewhat anxious; chimpanzees (and other primates) feel that way, too. That feeling is caused by physiological arousal, by the release of a variety of hormones and neurotransmitters like adrenaline that accelerate our heart rate, increase alertness, and prepare us to deal with physical confrontation. (Human conflicts are often verbal rather than physical, but our bodies react in a similar fashion.) When we feel that way physically, combined with the emotional stress that can accompany an argument, we often seek out physical contact with those we trust and care about. That physical contact makes us feel better emotionally and helps us calm down.

This is in part due to the fact that physical contact has a direct effect on physiological arousal; it stimulates the body to release other hormones and neurotransmitters to counter the effects of adrenaline. We share a deep psychological need for physical contact with those closest to us.

However there are also major differences between our reconciliation behavior and that of chimpanzees, the most obvious one being language. Reconciliation in humans often takes place through conversations —apologies, explanations, and verbal reaffirmations of the importance of a relationship. Since chimps do not have that method available to them, they can be expected to put even more emphasis on grooming. In fact, that is what happens.

By understanding the non-verbal reconciliation of chimpanzees and humans, as well as the importance of language in human reconciliation, we can better understand how social organization and social behavior affect what we get in fights over, when we fight, and to whom we can turn in conflict management.

Further Reading & Works Cited:

Aureli, F. and de Waal, F.B.M., eds.

(2000). Natural Conflict Resolution, University of California Press: Berkeley.

de Waal, F.B.M.

(1989). Peacemaking among Primates. Harvard University Press: Cambridge.

de Waal, F.B.M.

(1997). Good Natured: The Origins of Right and Wrong in Humans and Other Animals. Harvard University Press: Cambridge.

de Waal, F.B.M.

(1998). Chimpanzee Politics: Power and Sex among Apes, revised edition. Johns Hopkins University Press, Baltimore.

de Waal, F.B.M. and van Roosmalen, A.

(1979). Reconciliation and consolation among chimpanzees. Behavioural Ecology and Sociobiology, 5:55-66.

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