Evolutionary Influences on Assistance to Kin: Evidence from the Panel Study of Income Dynamics

Amid the changes that have diversified family life, studies have shown the continuing importance of attachment to kin through established patterns such as ties among full siblings and newer patterns such as efforts by donor-conceived individuals to find their donor siblings. Sociologists have good explanations for the diversity of family forms but not for the persistence kinship ties. This article argues that evolutionary processes focused on genetic relatedness can provide a partial explanation for both the persistence and expansion of kinship ties. It proposes that the easing of social constraints on family-related behaviors and the resulting expansion of choices may have increased the importance of genetic relatedness in producing the current patterns. illustrate this perspective, this article examines the consistency between patterns of financial assistance to kin and Hamilton's rule, derived from the evolutionary theory of inclusive fitness, using the 1985 to 2019 waves of the Panel Study of Income Dynamics (PSID).