Evolution and human behavior • Vol/Iss. 29(1) • Elsevier • • Published In • Pages: 1-18 •
Maternal grandmothers will tend to increase child survival more than paternal grandmothers (10).
In 9 of 13 (69%) populations where sufficient data were available, the presence of maternal grandmothers improved child survival. In 9 of 17 (53%) populations where sufficient data were available, the presence of paternal grandmothers improved child survival. (Hypothesis tested by observing the proportion of previous studies with the hypothesized effect. No formal statistical test)