Evolution and human behavior • Vol/Iss. 29(1) • Elsevier • • Published In • Pages: 1-18 •
The presence of older siblings who are potential helpers will have a positive effect on child survival (11).
5 of the 6 studies for which there was sufficient data found that potential sibling helpers has a positive effect on child survival. "Potential helpers" included only siblings several years older than the focal child. (Hypothesis tested by observing the proportion of previous studies with the hypothesized effect. No formal statistical test)