Causes, Consequences, and Kin Bias of Human Group Fissions

Abstract

Fissions of human communities are monumental occasions with consequences for cultural and genetic variation and divergence through time by means of serial founder effects. An ethnographic review shows that most human group fissions are fueled primarily by internal political conflict and secondarily by resource scarcity. As found for other social animals, human fissions lead to subgroups that have higher levels of relatedness as compared with the original community because of kin-biased assortment known as the lineal effect. Fission processes that increase the average relatedness of subgroups are important because relatedness governs how strongly kin/group selection favors social behaviors such as warfare, peacekeeping, and other forms of collection action. However, random individual assortment is not an appropriate null model for evaluating lineage assortment because nuclear families and extended households are expected to remain together, which in and of itself forces higher relatedness in smaller subgroups. We develop a lineage assortment index where low values represent subgroups with coefficients of relatedness near those expected if nuclear and extended households had chosen to associate into random groupings. Two fissions of Ache villages (Paraguay) are examples of this type of fission with a low lineage assortment index not significantly different from zero as evaluated with controlled simulations. On the other extreme, a lineage assortment index near unity represents a lineal fission that maximizes the relatedness of subgroups such as the perfect split of a lineage into sublineages. A fission of Piaroa (Venezuela) fits this scenario. While previous discussions of fission have emphasized similarities among human studies and even other social mammals, we highlight the full range of potential kin bias in the formation of new communities.

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References

  1. Alexander, R. D. (1990). How humans evolved: Reflections on the uniquely unique species. Museum of Zoology (Special Publication No. 1). Ann Arbor: University of Michigan.

  2. Altmann, J., Hausfater, G., & Atmann, S. A. (1985). Demography of Amboseli baboons. American Journal of Primatology, 8, 113–125.

    Article  Google Scholar 

  3. Alvard, M. (2009). Kinship and cooperation. Human Nature, 20, 394–416.

    Article  Google Scholar 

  4. Archie, E. A., Moss, C. J., & Alberts, S. C. (2006). The ties that bind: genetic relatedness predicts the fission and fusion of social groups in wild African elephants. Proceedings of the Royal Society of London. Series B: Biological Sciences, 273, 513–522.

    Article  Google Scholar 

  5. Århem, K. (1981). Makuna social organization: A study in descent, alliance, and the formation of corporate groups in the north-western Amazon. Stockholm: Almqvist & Wiksell.

    Google Scholar 

  6. Carneiro, R. (1987). Village splitting as a function of population size. In L. Donald (Ed.), Themes in ethnology and culture history. Meerut: Archana Publications.

    Google Scholar 

  7. Cavalli-Sforza, L. L., Piazza, A., Menozzi, P., & Mountain, J. (1988). Reconstruction of human evolution: bringing together genetic, archaeological, and linguistic data. Proceedings of the National Academy of Sciences of the United States of America, 85, 6002–6006.

    Article  Google Scholar 

  8. Chagnon, N. A. (1975). Genealogy, solidarity, and relatedness: limits to local group size and patterns of fissioning in an expanding population. Yearbook of Physical Anthropology, 19, 95–110.

    Google Scholar 

  9. Chagnon, N. A. (1976). Fission in an Amazonian tribe. New York Academy of Sciences, 16(1), 14–18.

    Google Scholar 

  10. Chagnon, N. A. (1979). Mate competition, favoring close kin, and village fissioning among the Yanomamö Indians. In N. A. Chagnon & W. A. Irons (Eds.), Evolutionary biology and human behavior. North Scituate: Duxbury Press.

    Google Scholar 

  11. Chagnon, N. A., & Bugos, P. E. (1979). Kin selection and conflict: An analysis of a Yanomamo ax fight. In N. A. Chagnon & W. A. Irons (Eds.), Evolutionary biology and human behavior (pp. 213–288). North Scituate: Duxbury Press.

    Google Scholar 

  12. Chapais, B. (2008). Primeval kinship: How pair bonding gave birth to human society. Cambridge: Harvard University Press.

    Google Scholar 

  13. Chepko-Sade, B. D., & Olivier, T. J. (1979). Coefficient of genetic relationship and the probability of intragenealogical fission in Macaca mulatta. Behavioral Ecology and Sociobiology, 5(3), 263–278.

    Article  Google Scholar 

  14. Dumont, J.-P. (1978). The headman and I: Ambiguity and ambivalence in the fieldworking experience. Austin: University of Texas Press.

    Google Scholar 

  15. Early, J. D., & Peters, J. F. (2000). The Xilixana Yanomami of the Amazon: History, social structure, and population dynamics. Gainesville: University Press of Florida.

    Google Scholar 

  16. Eggan, F. (1950). Social organization of the Western Pueblos. Chicago: University of Chicago Press.

    Google Scholar 

  17. Evans-Pritchard, E. E. (1940). The Nuer: A description of the modes of livelihood and political institutions of a Nilotic people. Oxford: Clarendon.

    Google Scholar 

  18. Fix, A. G. (1975). Fission-fusion and lineal effect: aspects of the population structure of the Semai Senoi of Malaysia. American Journal of Physical Anthropology, 43, 295–302.

    Article  Google Scholar 

  19. Fix, A. G. (1999). Migration and colonization in human microevolution. Cambridge: Cambridge University Press.

    Google Scholar 

  20. Fix, A. G. (2004). Kin-structured migration: causes and consequences. American Journal of Human Biology, 16, 387–394.

    Article  Google Scholar 

  21. Freedman, D. G. (1984). Village fissioning, human diversity, and ethnocentrism. Political Psychology, 5(4), 629–634.

    Article  Google Scholar 

  22. Goodenough, W. H. (1951). Property, kin, and community on Truk. New Haven: Yale University Publications.

    Google Scholar 

  23. Hamilton, W. D. (1964). The genetical evolution of social behavior, parts I and II. Journal of Theoretical Biology, 7, 1–52.

    Article  Google Scholar 

  24. Hill, K. R., & Hurtado, A. M. (1996). Ache life history: The ecology and demography of a foraging people. New York: Aldine de Gruyter.

    Google Scholar 

  25. Hill, K. R., Walker, R. S., Bozicevic, M., Eder, J., Headland, T., et al. (2011). Co-residence patterns in hunter-gatherer societies show unique human social structure. Science, 331, 1286–1289.

    Article  Google Scholar 

  26. Hoogland, J. L. (1995). The black-tailed prairie dog: Social life of a burrowing mammal. Chicago: University of Chicago Press.

    Google Scholar 

  27. Hunley, K. L., Spence, J. E., & Merriwether, D. A. (2008). The impact of group fissions on genetic structure in native South America and implications for human evolution. American Journal of Physical Anthropology, 135, 195–205.

    Article  Google Scholar 

  28. Kaplan, J. O. (1975). The Piaroa: A people of the Orinoco Basin. Oxford: Clarendon.

    Google Scholar 

  29. Keesing, R. M. (1978). Elota’s story: The life and times of a Solomon Islands big man. New York: Henry Holt & Company.

    Google Scholar 

  30. Kelly, R. L. (2013). The lifeways of hunter-gatherers: The foraging spectrum (2nd ed.). Cambridge: Cambridge University Press.

    Google Scholar 

  31. Levy, J. (1992). Orayvi revisited: social stratification in an “egalitarian” society. Santa Fe: School of American Research Press.

    Google Scholar 

  32. Lewis, M. P., Simons, G. F., & Fennig, C. D. (Eds) (2013). Ethnologue: Languages of the world, 17th edition. Dallas, Texas: SIL International. Online version: http://www.ethnologue.com.

  33. Marlowe, F. W. (2005). Hunter-gatherers and human evolution. Evolutionary Anthropology, 14, 54–67.

    Article  Google Scholar 

  34. Matta, R. (1970). A divided world: Social structure of the Apinayé. PhD dissertation. Harvard University.

  35. Maybury-Lewis, D. H. P. (1967). Akwa-Shavante society. Oxford: Clarendon.

    Google Scholar 

  36. Melatti, J. C. (1970). O sistema social Craô. PhD dissertation. Sao Paulo: Universidade de Sao Paulo.

  37. Melnick, D. J. (1987). The genetic consequences of primate social organization: a review of macaques, baboons and vervet monkeys. Genetics, 73, 117–135.

    Google Scholar 

  38. Melnick, D. J., & Kidd, K. K. (1983). The genetic consequences of social group fission in a wild population of rhesus monkeys (Macaca mulatta). Behavioral Ecology and Sociobiology, 12, 229–236.

    Article  Google Scholar 

  39. Metheny, J. D., Kalcounis-Ruepell, M. C., Bondo, K. J., & Brigham, R. M. (2008). A genetic analysis of group movement in an isolated population of tree-roosting bats. Proceedings of the Royal Society B, 275(1648), 2265–2272.

    Article  Google Scholar 

  40. Neel, J. V. (1967). The genetic structure of primitive human populations. Journal of Human Genetics, 12, 1–16.

    Google Scholar 

  41. Neel, J. V., & Salzano, F. M. (1966). Further studies on the Xavante Indians: some hypotheses-generalizations resulting from these studies. American Journal of Human Genetics, 19(4), 554–574.

    Google Scholar 

  42. Nsubuga, A. M., Robbins, M. M., Boesch, C., & Vigilant, L. (2008). Patterns of paternity and group fission in wild multimale mountain gorilla groups. American Journal of Physical Anthropology, 135, 263–274.

    Article  Google Scholar 

  43. O’Leary, T. J., Levinson, D., Hays, T. E., Hockings, P., Bennett, L. A., et al. (Eds.). (1994). Encyclopedia of world cultures. New York: Hall Publishing.

    Google Scholar 

  44. Oliver, D. (1955). A Solomon Islands society. Cambridge: Harvard University Press.

    Google Scholar 

  45. Olsen, C. L. (1976) The demography of new colony formation in a human isolate: An analysis and history. PhD dissertation, University of Michigan.

  46. Olsen, C. L. (1987). The demography of colony fission from 1878–1970 among the Hutterites of North America. American Anthropologist, 89, 823–837.

    Article  Google Scholar 

  47. Rappaport, R. A. (1968). Pigs for the ancestors: Ritual in the ecology of a New Guinea people. New Haven: Yale University Press.

    Google Scholar 

  48. Rodseth, L., Wrangham, R. W., Harrigan, A. M., & Smuts, B. B. (1991). The human community as a primate society. Current Anthropology, 32(3), 221–254.

    Article  Google Scholar 

  49. Sahlins, M. D. (1961). The segmentary lineage: an organization of predatory expansion. American Anthropologist, 63(2), 322–345.

    Article  Google Scholar 

  50. Silva, M. F. (2009). Romance de primas e primos: Uma etnografia do parentesco Waimiri-Atroari. Manaus: Valer Editora.

    Google Scholar 

  51. Smouse, P. E., Vitzthum, V. J., & Neel, J. V. (1981). The impact of random and lineal fission on the genetic divergence of small human groups: a case study among the Yanomama. Genetics, 98, 179–197.

    Google Scholar 

  52. Templeton, A. R. (1980). The theory of speciation via the founder principle. Genetics, 94, 1011–1038.

    Google Scholar 

  53. Titiev, M. (1972). The Hopi Indians of Old Oraibi: Change and continuity. Ann Arbor: University of Michigan Press.

    Google Scholar 

  54. Turnbull, C. M. (1965) The Mbuti Pygmies: an ethnographic survey. Anthropological papers of the American Museum of Natural History, 50, part 3. New York: American Museum of Natural History.

  55. Turner, V. W. (1957). Schism and continuity in an African society. Manchester: Manchester University Press.

    Google Scholar 

  56. Van Horn, R. C., Buchan, J. C., Altmann, J., & Alberts, S. C. (2007). Divided destinies: group choice by female savannah baboons during social group fission. Behavioral Ecology and Sociobiology, 61, 1823–1837.

    Article  Google Scholar 

  57. Verswijver, G. (1992). The club-fighters of the Amazon: Warfare among the Kaiapo Indians of Central Brazil. Gent: Rijksuniversiteit Te Gent.

    Google Scholar 

  58. Waterman, J. M. (2002). Delayed maturity, group fission and the limits of group size in female Cape ground squirrels (Xerus inauris: Sciuridae). Journal of Zoology, 256, 113–120.

    Article  Google Scholar 

  59. Whiteley, P. M. (1988). Deliberate acts: Changing Hopi culture through the Oraibi split. Tucson: University of Arizona Press.

    Google Scholar 

  60. Whiteley, P. M. (2008). The Orayvi split: A Hopi transformation. Anthropological Papers of the American Museum of Natural History. Number 87. New York: American Museum of Natural History.

  61. Wright, S. (1922). Coefficients of inbreeding and relationship. American Naturalist, 56, 330–338.

    Article  Google Scholar 

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Acknowledgments

This paper benefited from help and conversations with Peter Whiteley, Greg Blomquist, Rob Boyd, Craig Palmer, and Stephen Beckerman. Financial support was provided by a National Geographic Society Research and Exploration grant (#9165-12).

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Correspondence to Robert S. Walker.

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Walker, R.S., Hill, K.R. Causes, Consequences, and Kin Bias of Human Group Fissions. Hum Nat 25, 465–475 (2014). https://doi.org/10.1007/s12110-014-9209-0

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Keywords

  • Group splits
  • Lineal fissions
  • Human kinship
  • Genealogical relatedness
  • Cross-cultural comparison