It may be special treats found in their refrigerator each time we visited. Making macaroni necklaces. Teaching us to crochet. Allowing us to do what our parents never did. The always-available baby-sitting provided. The list can go on forever about the nurturing of our grandmothers and the importance of that in our individual development, as well as their place in our families.
Even more interesting is a new study based on computer simulations that supports the "grandmother hypothesis:" That we couldn't have done it without them!
The theory is that humans evolved longer adult lives than apes because grandmothers helped feed their grandchildren over some 24,000 to 60,000 years of development.
According to University of Utah professor anthropology Kristen Hawkes, author of the new study that was just published on October 24, "Grandmothering was the initial step toward making us who we are." It was published in the British journal Proceedings of the Royal Society B.
According to the study, when grandmothers help feed their grandchildren, after weaning, the daughters can have more children at shorter intervals.
By allowing their daughters to have more children, a few ancestral females who lived long enough to become grandmothers passed their longevity genes to more descendants, who had longer adult lifespans as a result.
Hawkes, along with University of Utah anthropologist James O’Connell and UCLA anthropologist Nicholas Blurton Jones proposed the grandmother hypothesis in 1997, and it's been debated ever since.
In the 1980s, Hawkes and O'Connell lived with Tanzania’s Hazda hunter-gatherer people and watched older women spend their days collecting tubers and other foods for their grandchildren. Except for humans, all other primates and mammals collect their own food after weaning.
However, over the past 2 million years, the environment changed and grew drier, with fewer forests where very young children could collect and eat fruits on their own.
“So moms had two choices,” Hawkes says. “They could either follow the retreating forests, where foods were available that weaned infants could collect, or continue to feed the kids after the kids are weaned. That is a problem for mothers because it means you can’t have the next kid while you are occupied with this one.”
The authors also say that evidence that grandmothering increases grandchildren’s survival is seen in 19th and 20th century Europeans and Canadians, and in Hazda and some other African people.
Tell us about your grandmother. How did she contribute to your development? What are (or were) your favorite memories of her? Share them in the comments below. Don't worry, we'll give equal time to grandfathers in a later post!
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