Grandparental Co-Residence and Intergenerational Conflict: Evidence from DHS African Countries

Ismael Munoz, IEGD-CCHS Spanish National Research Council (CSIC)
Alberto Palloni, University of Wisconsin-Madison

A candidate explanation for the evolution of menopause in a handful of species, including humans, is that it is a powerful antidote to otherwise potentially harmful intergenerational conflict that might commonly emerge in social groups. Curtailing reproductive life span by accelerating rates of reproductive senescence relative to somatic senescence is an effective mechanism to reduce fitness costs to overlapping competing generations. It follows that, under demographic conditions experienced by human groups that host increased reproductive overlap between generations, one should observe significant deleterious effects to fitness, particularly among the most vulnerable members. These deleterious effects effectively operate as the sieve of the natural selection of the trait. We use Demographic and Health Surveys (DHS) information on a large set of demographically diverse populations and random and fixed effects models to show that joint co-residence of grandmothers, mothers and their offspring and grand offspring, increases the risk of mortality and malnutrition in children below age 5. We also show that the central mediating mechanism that generates these outcomes is the biased distribution by birth order and maternal age at birth of the offspring and grand offspring involved.

Keywords: Data and Methods, Older Adults and Intergenerational Relations, Mortality and Longevity, Health and Morbidity

See extended abstract.