The grandmother effect and the uniqueness of the human aging phenotype.

This issue of Gerontology includes a response by van Bodegom et al. to Herndon's recent article on the implications of the grandmother hypothesis for studies of aging and cognition. Although this hypothesis will doubtlessly continue to stimulate discussion, we focus here on our contention that human and non-human primate life histories have evolved essential differences and that these should be addressed in studies comparing aging in humans and chimpanzees.