Behavioral and Brain Sciences

Open Peer Commentary

Fitness effects of grandparental investments in contemporary low-risk societies

Ralf Kaptijna1 and Fleur Thomesea1

a1 Faculty of Social Sciences, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands.


Coall & Hertwig (C&H) suggest that, because grandparental investments do not impact on child mortality in low-risk societies, fitness effects are not plausible any more. We found that grandparental investments could very well alleviate contemporary constraints on fertility. Cultural factors may influence both the occurrence and impact of grandparental investments.