The authors of this new study suggest that the secret to human longevity is being grandparents. In fact, one of the leading ideas for human longevity is called the Grandmother Hypothesis—the idea that, through their efforts, maternal grandmothers can increase their fitness by helping improve the survival of their grandchildren, thereby freeing up their daughters to have more children. Such fitness effects help ensure that the grandmother's DNA is passed down.

In their paper, the researchers take the kernel of that idea—intergenerational transfers, or resource sharing between old and young—and show that it, too, has played a fundamental role in the force of selection at different ages. The researchers' findings can be summarized as follows, "What this suggests is that human longevity is really a story about cooperation."

This empowering (and MEA-centric) message reminds me of one of my all-time favorite TED talks about the value of grandmothers in Africa, which I captured in this previous blog post. I hope you don't mind me resurfacing it.