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Publication - Professor Mhairi Gibson

    Does kin selection theory help to explain support networks among farmers in South-Central Ethiopia?


    Clech, L, Hazel, A & Gibson, M, 2019, ‘Does kin selection theory help to explain support networks among farmers in South-Central Ethiopia?’. Human Nature: An Interdisciplinary Biosocial Perspective.


    Social support networks play a key role in human livelihood security, especially in vulnerable communities. Here we explore how evolutionary ideas of kin selection and intra-household resource competition can explain individual variation in daily-support network size and composition in a South-Central Ethiopian agricultural community. We consider both domestic and agricultural help across two generations with different large-wealth transfer norms that yield different contexts for sibling competition.
    For farmers who inherited land rights from family, first-borns were more likely to report daily support from parents and to have larger non-parental kin networks (n=176). Compared with other farmers, first-borns were also more likely to reciprocate their parents’ support, and to help non-parental kin without reciprocity.
    For farmers who received land rights from the government (n=150), middle-born farmers reported more non-parental kin in their support networks compared with other farmers; non-reciprocal interactions were particularly common in both directions. This suggests a diversification of adult support network to non-parental kin, possibly in response to a long-term parental investment disadvantage of being middle-born sons. In all instances (with or without land inheritance), last-born farmers were the most disadvantaged in terms of kin support.
    Overall, we found that non-reciprocal interactions among farmers follow predictions of kin selection, and were more common for kin versus non-kin, and for close kin versus distant kin. Direct reciprocity explained a substantial part of the support received from kin, suggesting the importance of the combined effects of kin selection and reciprocity for investment from kin.

    Full details in the University publications repository