Learning, Menopause and the Human Adaptive Complex

The talk will present a general theory of growth and aging, and then extends it to examine the life history implications of the skills-based foraging niche, characteristic of the human evolutionary past. The theory proposes that the role of knowledge, skill acquisition and transfers in determining economic productivity and resource distribution is the distinctive feature of the traditional human ecology that is responsible for the evolution of prolonged development, menopause and a 70 year lifespan. The theory also proposes that male reproductive cessation and post-reproductive investment in descendants is a fundamental characteristic of humans living in traditional foraging and simple horticultural economies. The talk will present evidence relevant to the theory. The data show that after ceasing to reproduce, both men and women provide net economic transfers to children and grandchildren. Given this pattern of economic productivity, delays in menopause would produce net economic deficits within families. The data also show that reproductive decline in human females is more rigid than in chimpanzees, and most human males undergo reproductive cessation at the same time as their wives. In addition, the modal age at death for adults in traditional societies is approximately 70 years of age. By this age, people have no dependent children, and a declining number of grandchildren to support.