http://www.jstor.org/pss/3059361
The Emergence of Humans: The Coevolution of Intelligence and Longevity
with Intergenerational Transfers, by Hillard S. Kaplan and Arthur J.
Robson =A9 2002 National Academy of Sciences.
Proceedings of the National Academy of Sciences of the United States
of America, Vol. 99, No. 15 (Jul. 23, 2002), pp. 10221-10226
Abstract
Two striking differences between humans and our closest living
relatives, chimpanzees and gorillas, are the size of our brains
(larger by a factor of three or four) and our life span (longer by a
factor of about two). Our thesis is that these two distinctive
features of humans are products of coevolutionary selection. The large
human brain is an investment with initial costs and later rewards,
which coevolved with increased energy allocations to survival. Not
only does this theory help explain life history variation among
primates and its extreme evolution in humans; it also provides new
insight into the evolution of longevity in other biological systems.
We introduce and apply a general formal demographic model for
constrained growth and evolutionary tradeoffs in the presence of life-
cycle transfers between age groups in a population.
