Grandmother hypothesis (Hadza study)
Hipótesis de la abuela (estudio de los hadza)
- Date
- 1989 (formulación: 1998) · confidence medium
- Place
- Lake Eyasi, Manyara, Tanzania
- Credited to
- Kristen Hawkes, James O'Connell and Nicholas Blurton Jones
- Field
- Life & health
⚠️ Disputed: the sources disagree.
What was discovered
Observing the Hadza, hunter-gatherers of Tanzania, they found that grandmothers dug tubers for their weaned grandchildren. They proposed that this work explains the evolution of menopause and of long human lifespans.
Observations published in 1989; the formal hypothesis dates from 1998 (PNAS). It is still debated: some historical-population studies support it and others do not, and the importance of grandmothers' contributions varies by environment.
What it led to
- mathematical models of the evolution of human longevity
- reinterpretation of age and sex roles among hunter-gatherers
- debate over alternatives such as the caregiver and sexual-selection hypotheses