The aging brain: The cognitive reserve hypothesis and hominid evolution
Article first published online: 27 OCT 2005
Copyright © 2005 Wiley-Liss, Inc.
American Journal of Human Biology
Volume 17, Issue 6, pages 673–689, November/December 2005
How to Cite
Allen, J. S., Bruss, J. and Damasio, H. (2005), The aging brain: The cognitive reserve hypothesis and hominid evolution. Am. J. Hum. Biol., 17: 673–689. doi: 10.1002/ajhb.20439
- Issue published online: 27 OCT 2005
- Article first published online: 27 OCT 2005
- Manuscript Accepted: 3 AUG 2005
- Manuscript Revised: 22 JUL 2005
- Manuscript Received: 29 MAR 2005
Compared to other primates, humans live a long time and have large brains. Recent theories of the evolution of human life history stages (grandmother hypothesis, intergenerational transfer of information) lend credence to the notion that selection for increased life span and menopause has occurred in hominid evolution, despite the reduction in the force of natural selection operating on older, especially post-reproductive, individuals. Theories that posit the importance (in an inclusive fitness sense) of the survival of older individuals require them to maintain a reasonably high level of cognitive function (e.g., memory, communication). Patterns of brain aging and factors associated with healthy brain aging should be relevant to this issue. Recent neuroimaging research suggests that, in healthy aging, human brain volume (gray and white matter) is well-maintained until at least 60 years of age; cognitive function also shows only nonsignificant declines at this age. The maintenance of brain volume and cognitive performance is consistent with the idea of a significant post- or late-reproductive life history stage. A clinical model, “the cognitive reserve hypothesis,” proposes that both increased brain volume and enhanced cognitive ability may contribute to healthy brain aging, reducing the likelihood of developing dementia. Selection for increased brain size and increased cognitive ability in hominid evolution may therefore have been important in selection for increased lifespan in the context of intergenerational social support networks. Am. J. Hum. Biol. 17:673–689, 2005. © 2005 Wiley-Liss, Inc.