It turns out the relationships we have today — from our families to our love interests — may all stem from one thing: grandma's cooking. The mouth-watering meals we obsess over now were just as meaningful over 2 million years ago, even if they probably didn't taste quite as good.
We owe grandmothers around the world and across many, many generations huge thanks for several important parts of human evolution, according to Kristen Hawkes, PhD, distinguished professor of anthropology at the University of Utah and senior author of a September 2015 study published in Proceedings of the National Academy of Sciences.
In the late 1990s, Dr. Hawkes first established her "grandmother hypothesis," which goes like this: Millions of years ago, women rarely lived past childbearing years and raised one child at a time. A mother typically didn't have another child until her first child was completely weaned and able to feed himself.
Then a new barrier to raising children was introduced when humans began to rely on food that was harder for children to get on their own (think digging for potatoes). This would have meant mothers had to wait even longer to have their next children. But — grandma's cooking to the rescue! — older women began to help feed their grandchildren so mothers could have more babies.
"The grandmothers — whose own fertility was ending — could make a difference to the number of descendants they'd leave if they helped feed the dependent kids," Hawkes explains. "The grandmothers who lived longer could help more and have more longer-lived grandkids, which over time via evolution meant that humans started living longer."
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For their latest paper, Hawkes and a team of researchers used computer simulations to take the grandmother hypothesis one step further: They wanted to see if grandma's cooking had any effect on human pair bonding ("going steady," essentially).
The traditional reasoning behind why humans bonded in pairs is mutual payoff: The woman and children are supported and protected by the man "bringing home the bacon," and the man gets to pass on his genes via multiple descendants.
But Hawkes and her team have a different theory: "Our hypothesis makes pair bonding the consequence of 'grandmothering,'" she says.
Hawkes and her team argue that — thanks to grandmothers helping feed and raise their grandchildren — the human population and lifespan increased, which made mating more competitive for men. There were more people living longer, but women were still only fertile for a certain length of time. (Hello, menopause.) So this meant there were more older men competing for the chance to mate with younger, still fertile women.
In this competition, the most successful men were those who guarded one woman rather than seeking multiple mates. They had better odds of creating more descendants with one woman rather than attempting to guard and mate with lots of women. Voila, pair bonding!
And so, in the end, it looks like grandma's cooking may have been responsible for our ancestors living longer, joining into special relationships and even developing the nuclear family as we know it. So whether you like it or not, next time you eat grandma's casserole, show some appreciation, will you?