Open Peer Commentary
The effects of grandparental investment in relatives are apparent in human groups, suggesting that a postreproductive period in humans is selective. Although investment of relatives in kin produces obvious benefits for kin groups, selection for a postreproductive period in humans is not supported by evidence from chimpanzees. Instead, grandparental investment is likely a recent phenomenon of longevity, rather than an evolved feature.
Grandparental investment: Past, present, and future David A. Coall and Ralph Hertwig School of Psychiatry and Clinical Neurosciences, University of Western Australia, Fremantle, Western Australia 6160, Australia. firstname.lastname@example.org http://www.uwa.edu.au/people/david.coall; Department of Psychology, University of Basel, 4055 Basel, Switzerland. email@example.com http://www.psycho.unibas.ch/hertwig