When Did People Leave Africa?
We know that our ancestors diverged from other apes in Africa. And for millions of years that's where they remained. But at some point hominins expanded to other continents, in a series of waves that included our own species roughly 70,000 years ago.
When was the first trip out? The clearest answer to that question would come from skeletons. The oldest skeletons of hominins yet found outside of Africa are about 1.7 million years old, found in the republic of Georgia. But this week, a team of researchers who have worked for years digging into a giant gulley in China, say they have found tools as old as 2.1 million years.
This is much more than just a matter of re-pinning an event to a new page of the calendar. The age of these tools--if they are tools--says a lot about what sort of folks walked out of Africa. Were they tall, big-brained people like us, or were they basically upright apes?
I dig into this fascinating study this week in the New York Times.
1. National Geographic's Simon Worrall interviewed me about my new book.
When I told my wife the title of your book, and that it was about heredity, she said: “I got my mother’s laugh and voice from being around her.” So, Carl, is it genes or the environment—nature or nurture—that make us who we are?
No one has done a rigorous genetic study of the genetic inheritance of laughter. [laughs] But researchers have studied behavior in general, and genetics, which show that there are different kinds of behavior and aspects of people’s personalities that are “heritable.” This means that if you look at the variation in a trait in a big group of people, some of that variation is due to the genes that they inherit. Identical twins, for instance, will tend to be more similar to each other in that trait than their siblings.
But I would be surprised if laughter had even 10 percent heritability. Genes you inherit may play a role in your laugh being somewhat similar to your parents’, but you’re also growing up with them and listening to them laughing, and we’re a very imitative species. There’s no way you could drill down and say we have identified that 10 percent of your laugh came from your DNA. We’d like it to happen. That’s why consumer genetic tests are incredibly popular. Somehow we want to look inside our DNA and get a precise measurement of why we are the way we are.
Certainly our genes are enormously important, but they’re not the only things that are passed down from our parents. I would argue that you should think beyond genes when trying to understand the full scope of heredity. For example, we humans are cultural animals and culture works like its own form of heredity. You’re probably already discovering, for example, that your children or grandchildren are a lot better than you are at using a smart phone. They may go on to think about a new way of designing phones, which will then get passed down to future generations.
You can read the rest here.
2. Thanks to Thrillist for naming She Has Her Mother's Laugh one of the best books of 2018 so far!
3. The new issue of O Magazine is out, calling the book "a story filled with palace intrigue and breathtaking innovation.”
4. Here's a podcast recording of my conversation at the Silicon Valley Commonwealth Club from last month.
September 20, 2018 University of Bath (UK), Evolution in the 21st Century
October 4, 2018 92nd Street Y, New York: "What Makes Us Human? Panel with Maria Konnikova, Nathan Lents, and Sebastian Seung.
October 17, 2018 Colorado State University: Murray Honors Visiting Scholar Lecture (details to come)
October 19, 2018 CSICon, Las Vegas
October 25, 2018 Mount Holyoke College (details to come)
November 7, 2018 University of Pennsylvania, Philadelphia (details to come)
November 13, 2018 House of Speakeasy, New York (details to come)
November 14, 2018 Stevens Institute of Technology, Hoboken, NJ (details to come)
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Best wishes, Carl
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