Reconciliation, or peaceful postconflict interaction, can restore the usual pattern of interaction between social partners after open conflict has disrupted it—i.e., it can resolve conflicts. Researchers have documented reconciliation in >20 primate species, but the tendency to reconcile typically varies among dyads and dyad classes. The valuable-relationships hypothesis proposes that differences in the value of social relationships account for much of this variation. Value depends on how likely partners are to act in ways that benefit each other, where the benefits are ultimately direct or indirect increases in fitness. Researchers have responded to studies that have tested predictions of the hypothesis with extensive, if not universal, support. For example, kin show higher conciliatory tendencies than nonkin in many species, and conciliatory tendencies between unrelated females are high in several cercopithecines in which nonkin agonistic support is important for rank acquisition and maintenance. However, most of the support is indirect, because we lack direct evidence on the link between assays of relationship value and fitness. Also, some studies have methodological weaknesses, e.g., analyses based on pooled data and insufficient sample sizes. I review evidence in favor of the hypothesis with special attention to studies that come closest to providing evidence for predicted fitness effects. I also present new data on postconflict interactions between adult male chimpanzees at Ngogo that show how often pairs of males formed coalitions and how much time they spent grooming influenced the likelihood that they would reconcile after conflicts, and that allies were particularly likely to reconcile and to do so by grooming each other. The most important future research direction is to integrate detailed data on conflict management, analyzed at the level of dyads, with long-term data on reproductive success, such as that now available from several study sites, on the same populations.
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REFERENCES
Alberts, S., and Altmann, J. (2004). Patterns of coalition formation by adult female baboons in Amboseli, Kenya. Anim. Behav. 67: 573–582.
Altmann, J., and Alberts, S. (2003). Variation in reproductive success viewed from a life history perspective in baboons. Am. J. Hum. Biol. 15: 401–409.
Arnold, K., and Barton, R. A. (2001). Post-conflict behavior of leaf monkeys (Trachypithecus obscurus). I. Reconciliation. Int. J. Primatol. 22: 243–266.
Arnold, K., and Whiten, A. (2001). Post-conflict behavior of wild chimpanzees (Pan troglodytes schweinfurthii) in the Budongo Forest, Uganda. Behaviour 138: 649–690.
Aureli, F. (1992). Post-conflict behavior among wild long-tailed macaques (Macaca fascicularis). Behav. Ecol. Sociobiol. 31: 329–337.
Aureli, F., Cords, M., and van Schaik, C. P. (2002). Conflict resolution following aggression in gregarious animals: A predictive framework. Anim. Behav. 64: 325–343.
Aureli, F., Das, M., and Veenema, H. C. (1993). Differential kinship effects on reconciliation in three species of macaques (Macaca fascicularis, M. fuscata, and M. sylvanus). J. Comp. Psychol. 11: 91–99.
Aureli, F., van Schaik, C. P., and van Hooff, J. A. R. A. M. (1989). Functional aspects of reconciliation among captive long-tailed macaques (Macaca fascicularis). Am. J. Primatol. 19: 39–51.
Baker, K., and Smuts, B. B. (1994). Social relationships of female chimpanzees: Diversity between captive social groups. In Wrangham, W. W., McGrew, W. C., de Waal, F. B. M., and Heltne, P. G. (eds), Chimpanzee Cultures. Harvard University Press, Cambridge, MA, pp. 227–242.
Barrett, L., and Henzi, S. P. (2001). The utility of grooming in baboon troops. In Noe, R., van Hooff, J. A. R. A. M., and Hammerstein, P. (eds), Economics in Nature: Social Dilemmas, Mate Choice, and Biological Markets. Cambridge University Press, Cambridge, UK, pp. 119–145.
Boesch, C., and Boesch-Achermann, H. (2000). The Chimpanzees of the Tai Forest. Oxford University Press, Oxford.
Butynski, T. (1990). Comparative ecology of blue monkeys (Cercopithecus mitis) in high- and low-density subpopulations. Ecol. Monogr. 60: 126.
Casperd, J. M. (1997). The Evolution of Reconciliation Within the Primate Order. Unpublished Ph.D. Thesis, University of Liverpool.
Castles, D., Aureli, F., and de Waal, F.B.M. (1996). Variation in conciliation tendency and relationship quality across groups of pigtail macaques. TAnim. Behav.T 52: 389--403.
Castles, D., and Whiten, A. (1998). Post-conflict behavior of wild olive baboons. I. Reconciliation, redirection, and consolation. Ethology 104: 126147.
Chapais, B. (1992). The role of alliances in the social inheritance of rank among female primates. In Harcourt, A. H., and de Waal, F. B. M. (eds.), Coalitions and Alliances in Humans and Other Animals. Oxford University Press, Oxford, pp. 29–60.
Chapais, B. (2001). Primate nepotism: what is the explanatory value of kin selection? Int. J. Primatol. 22: 203–229.
Colmenares, F., and Lazaro-Perea, C. (1994). Greeting and grooming grooming during social conflicts in baboons. In Roeder, J. J., Thierry, B., Anderson, J. R., and Herrenschmidt, N. (eds.), Current Primatology, Vol. 2: Social Development, Learning, and Behavior, pp. 165–174. Université Louis Pasteur, Strasbourg.
Cooper, M. A., Bernstein, I. S., and Hemelrijk, C. K. (2005). Reconciliation and relationship quality in Assamese macaques. Am. J. Primatol. 25: 269–282.
Cords, M. (1992). Post-conflict reunions and reconciliation in long-tailed macaques. Anim. Behav. 44: 57–61.
Cords, M. (1997). Friendship, alliances, reciprocity, and repair. In Whiten, A., and Byrne, R. W. (eds.), Machiavellian Intelligence II. Cambridge University Press, Cambridge, pp. 24–49.
Cords, M., and Aureli, F. (1993). Patterns of reconciliation among juvenile long-tailed macaques. In Pereira, M., and Fairbanks, L. A. (eds.), Juvenile Primates. Oxford University Press, Oxford, pp. 271–284.
Cords, M., and Aureli, F. (2000). Reconciliation and relationship qualities. In Aureli, F., and de Waal, F. B. M. (eds.), Natural Conflict Resolution, University of California Press, Berkeley, pp. 177–198.
Cords, M., and Killen, M. (1998). Conflict resolution in human and nonhuman primates. In Langer, J., and Killen, M. (eds.), Piaget, Evolution, and Development. Lawrence Erlbaum, Mahwah, NJ, pp. 193–219.
Cords, M., and Thurnheer, S. (1993). Reconciliation with valuable partners by long-tailed macaques. Ethology 93: 315–325.
Demaria, C., and Thierry, B. (2001). A comparative study of reconciliation in rhesus and Tonkean macaques. Behaviour 138: 397–410.
de Waal, F. B. M. (1982). Chimpanzee Politics. Johns Hopkins University Press, Baltimore.
de Waal, F.B.M. (1986). Integration of dominance and social bonding in primates. Quart. Rev. Biol. 61: 459--479.
de Wall, F.B.M. (2000). The first kiss: Foundations of conflict resolution research in animals. In Aureli, F. and de Waal, F.B.M. (eds.), Natural Conflict Resolution. University of California Press, Berkeley, pp. 15--33.
de Waal, F.B.M. and Aureli, F. (1996). Consolation, reconciliation, and a possible cognitive difference between macaques and chimpanzees. In Russon, A.E., Bard, K.A., and Parker, S.T. (eds.), Reaching Into Thought. Cambridge University Press, Cambridge, pp. 80-110.
de Waal, F. B. M., and Aureli, F. (1997). Conflict resolution and distress alleviation in monkeys and apes. Ann. NY Acad. Sci. 807: 317–328.
de Waal, F. B. M., and van Roosmalen, A. (1979). Reconciliation and consolation among chimpanzees. Behav. Ecol. Sociobiol. 5: 55–66.
de Waal, F. B. M., and Yoshihara, D. (1983). Reconciliation and redirected affection in rhesus monkeys. Behaviour 85: 224–241.
Fuentes, A., Malone, N., Sanz, C., Matheson, M., and Vaughan, L. (2002). Conflict and post-conflict behavior in a small group of chimpanzees. Primates 43: 223–236.
Grinnell, J., Packer, C., and Pusey, A. E. (1995). Cooperation in male lions: Kin selection, reciprocity, or mutualism? Anim. Behav. 49: 95–105.
Gros-Louis, J., Manson, J. H., and Perry, S. (2003). Violent coalitionary attacks and intraspecific killing in wild white-faced capuchin monkeys (Cebus capucinus). Primates 44: 341–346.
Harcourt, A. H. (1987). Dominance and fertility in female primates. J. Zool. Lond. 213: 471–487.
Hemelrijk, C. K. (1990). Models of, and tests for, reciprocity, unidirectionality, and other social interaction patterns at group level. Anim. Behav. 39: 1013-1029.
Hemelrijk, C. K. (1991). A matrix partial correlation test used in correlations of reciprocity and other social interaction patterns at group level. J. Theor. Biol. 143: 405–420.
Henzi, P., and Barrett, L. (2003). Evolutionary ecology, sexual conflict, and behavioral differentiation among baboon populations. Evol. Anthropol. 12: 217–230.
Judge, P. (1991). Dyadic and triadic reconciliation in pigtail macaques (Macaca nemestrina). Am. J. Primatol. 23: 225–237.
Kappeler, P., and van Schaik, C. P. (1992). Methodological and evolutionary aspects of reconciliation in primates. Ethology 92: 51–69.
Koyama, M. (2001). The long-term effects of reconciliation in Japanese macaques Macaca fuscata. Ethology 107: 975–987.
Kummer, H. (1978). On the value of social relationships to nonhuman primates: A heuristic scheme. Soc. Sci. Infor. 17: 687–705.
Kutsukake, N., and Castles, D. L. (2004). Reconciliation and post-conflict third-party affiliation among wild chimpanzees in the Mahale Mountains, Tanzania. Primates 45: 157–165.
Lewis, R. J. (2002). Beyond dominance: The importance of leverage. Quart. Rev. Biol. 77: 149–164.
Lwanga, J. S., Butynski, T., and Struhsaker, T. T. (2000). Tree population dynamics in Kibale National Park, Uganda 1975–1998. Afr. J. Ecol. 38: 238–247.
Majolo, B., Ventura, R., and Koyama, N. (2005). Postconflict behavior among male Japanese macaques. Int. J. Primatol. 26: 321–336.
Manson, J. H., Perry, S., and Stahl, D. (2005). Reconciliation in wild white-faced capuchins (Cebus capucinus). Am. J. Primatol. 65: 205–219.
Manson, J. H., Rose, L. M., Perry, S., and Gros-Louis, J. (1999). Dynamics of female-female relationships in wild Cebus capucinus: Data from two Costa Rican sites. Int. J. Primatol. 20: 679–706.
Nishida, T. (1983). Alpha status and agonistic alliance in wild chimpanzees (Pan troglodytes schweinfurthii). Primates 24: 318–336.
Nishida, T., and Hosaka, K. (1996). Coalition strategies among adult male chimpanzees of the Mahale Mountains, Tanzania. In McGrew, W. A., Marchant, L. A., and Nishida, T. (eds.), Great Ape Societies. Cambridge University Press, Cambridge, pp. 114–134.
Palagi, E., Paoli, T., and Tarli, S. B. (2004). Reonciliation and consolation in captive bonobos. Am. J. Primatol. 62: 15–30.
Palombit, R. A., Seyfarth, R. M., and Cheney, D. L. (1997). The adaptive value of “friendships” to female baboons: Experimental and observational evidence. Anim. Behav. 54: 599–614.
Perry, S. (1996). Female-female social relationships in wild white-faced capuchin monkeys, Cebus capucinus. Am. J. Primatol. 40: 167–182.
Perry, S. (1997). Male-female social relationships in wild white-faced capuchin monkeys, Cebus capucinus. Behaviour 134: 477–510.
Perry, S. (1998). Male-male social relationships in wild white-faced capuchins, Cebus capucinus. Behaviour 135: 1–34.
Preuschoft, S., Wang, X., Aureli, F., and de Waal, F. B. M. (2002). Reconciliation in captive chimpanzees: A re-evaluation with controlled methods. Int. J.Primatol. 23: 29–50.
Seyfarth, R. M. (1977). A model of social grooming among adult female monkeys. J. Theor. Biol. 65: 671–698.
Silk, J. B. (1997). The function of peaceful post-conflict contacts among primates. Primates 38: 265–279.
Silk, J. B., Alberts, S. C., and Altmann, J. (2003). Social bonds of female baboons enhance infant survival. Science 302: 1231–1234.
Silk, J. B. Alberts, S. C., and Altmann, J. (2004). Patterns of coalition formation by adult female baboons in Amboseli, Kenya. Anim. Behav. 67: 573--582.
Silk, J. B., Cheney, D. L., and Seyfarth, R. M. (1996). The form and function of post-conflict interactions between female baboons. Anim. Behav. 52: 259–268.
Sommer, V., Denham, A., and Little, K. (2002). Post-conflict behavior of wild Indian langur monkeys: Avoidance of opponents but rarely affinity. Anim. Behav. 63: 637–648.
Struhsaker, T. T. (1997). The Ecology of an African Rainforest. University Press of Florida, Gainesville.
Takahata, Y., Huffman, M. A., Suzuki, S., Koyama, N., and Yamagiwa, J. (1999). Why dominants do not consistently attain high mating and reproductive success: A review of longitudinal Japanese macaque studies. Primates 40: 143–158.
Thierry, B. (1990). L’état d’équilibre entre comportements agonistiques chez un groupe de macaques Japonais (Macaca fuscata). Compte Rend. Acad. Sci. Paris 310(III): 35–40.
Thierry, B. (2000). Covariation of conflict management patterns across macaque species. In Aureli, F., and de Waal, F. B. M. (eds.), Natural Conflict Resolution. University of California Press, Berkeley, pp. 106–128.
Tutin, C. E. G. (1979). Mating patterns and reproductive strategies in a community of wild chimpanzees (Pan troglodytes schweinfurthii). Behav. Ecol. Sociobiol. 6: 29--38.
van Hooff, J. A. R. A. M., and van Schaik, C. P. (1994). Male bonds: affiliative relationships among nonhuman primate males. Behaviour 130: 309–337.
van Noordwijk, M. A., and van Schaik, C. P. (1999). The effects of dominance rank and group size on female lifetime reproductive success in wild long-tailed macaques (Macaca fascicularis). Primates 40: 105–130.
van Schaik, C. P. (1989). The ecology of social relationships amongst female primates. In Standen, V., and Foley, R. A. (eds.), Comparative Socioecology. Blackwell, London, pp. 195–218.
van Schaik, C. P., and Aureli, F. (2000). The natural history of valuable social relationships in primates. In Aureli, F., and de Waal, F. B. M. (eds.), Natural Conflict Resolution. University of California Press, Berkeley, pp. 307–333.
Veenema, H. C., Das, M., and Aureli, F. (1994). Methodological improvements for the study of reconciliation. Behav. Process. 31: 29–38.
Watts, D. P. (1995). Post-conflict events in wild mountain gorillas (Mammalia, Hominoidea) I. Social interactions between opponents. Ethology 100: 139–157.
Watts, D. P. (1998). Coalitionary mate guarding by male chimpanzees at Ngogo, Kibale National Park, Uganda. Behav. Ecol. Sociobiol. 44: 43–55.
Watts, D. P., Colmenares, F., and Arnold, K. (2000). Redirection, consolation, and male policing. In Aureli, F., and de Waal, F. B. M. (eds.), Natural Conflict Resolution. University of California Press, Berkeley, pp. 281–301.
Watts, D. P., and Mitani, J. C. (2001). Boundary patrols and intergroup aggression in wild chimpanzees. Behaviour 138: 299–327.
Watts, D. P., Muller, M., Amsler, S., Mbabazi, G., and Mitani, J. C. (2006). Lethal intergroup aggression by chimpanzees in the Kibale National Park, Uganda. Amer. J. Primatol. 68: 161-180.
Williams, J. M., Oehlert, G. W., Carlis, J. V, and Pusey, A. E. (2004). Why do male chimpanzees defend a group range? Anim. Behav. 68: 523–532.
Williams, J. M., Pusey, A. E., Carlis, J. V., Fram, B. P., and Goodall, J. (2002). Female competition and male territorial behavior influence female chimpanzees’ ranging patterns. Anim. Behav. 63: 347–360.
Wilson, M. L., Hauser, M. D., and Wrangham, R. W. (2001). Does participation in intergroup depend on numerical assessment, range location, or rank for wild chimpanzees? Anim. Behav. 61: 1203–1216.
Wilson, M. L., and Wrangham, R. W. (2003). Intergroup relations in chimpanzees. Annu. Rev. Anthropol. 32: 363–392.
Wittig, R. M., and Boesch, C. (2003). “Decision making” in conflicts of wild chimpanzees (Pan troglodytes): An extension of the relational model. Behav. Ecol. Sociobiol. 54: 491–504.
Wrangham, R. W. (1999). Evolution of coalitionary killing. Yrbk. Phys. Anthro. 42: 1–30.
ACKNOWLEDGMENTS
I thank the Uganda Wildlife Authority, The Ugandan Council for Science and Technology, and Makerere University for permission to do research at Ngogo. Dr. Gilbert Isibirye Basuta and Dr. John Kasenene provided invaluable support for research efforts at Ngogo over the years, and research on the chimpanzees there would be difficult without the collaboration and support of Dr. Jeremiah Lwanga and the expert field assistance of Adolph Magoba, Godfrey Mbabazi, Lawrence Ndagezi, and Alfred Tumusiime. I thank Nicola Koyama for inviting me to participate in the symposium on conflict management at the Congress of the International Primatological Society in Torino in August, 2004. Earlier versions of this manuscript benefited from comments by 2 anonymous reviewers. The L. S. B. Leakey Foundation and Yale University supported my research at Ngogo.
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Watts, D.P. Conflict Resolution in Chimpanzees and the Valuable-relationships Hypothesis. Int J Primatol 27, 1337–1364 (2006). https://doi.org/10.1007/s10764-006-9081-9
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DOI: https://doi.org/10.1007/s10764-006-9081-9