New book 'Eve' dispels myths about human evolution and details female body's role

Transcript

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Amna Nawaz: We often talk about human origins as the evolution of man, but what if we saw it as the evolution of woman?

A new book argues for a better understanding of our beginnings, with critical implications for our present.

Jeffrey Brown explains. And it's for our arts and culture series, Canvas.

Jeffrey Brown: Where do we come from and how did we evolve into the beings and bodies we are today? It's a story that continues to fascinate at the American Museum of Natural History in New York.

Human origins.

Cat Bohannon, Author, "Eve: How the Female Body Drove 200 Million Years of Human Evolution": Yes, here we are.

Jeffrey Brown: Where Cat Bohannon first came as a child and now with a call for a new way of looking at human development.

Cat Bohannon: We have a lot of stories about the evolution of mammals. We especially have a lot of stories about the evolution of humanity and its possible past.

But, weirdly, in so many of these stories, the female is at best a side character. You know what I mean? But, increasingly, in many different disciplines, whether it's anthropology or in biology, we're putting that female back in the picture. And that actually changes how we tell that story.

Jeffrey Brown: Bohannon tells the story in "Eve: How the Female Body Drove 200 Million Years of Human Evolution."

In fact, with personal whimsy as well as scientific data, she writes of many Eves, starting with a creature she nicknames Morgie, perhaps the first ever breast-feeder.

Cat Bohannon: It's delightful that the reason someone like me might have breasts is because there is this little weaselly creature 200 million years ago living under the literal feet of dinosaurs and she starts lactating. And that's why, right? So that's just fun.

Jeffrey Brown: And she gives us other Eves who bring tools, language and a whole lot more into the tale of the human species as a whole.

Cat Bohannon: It's really rewarding to remember how deeply ancient these things are, that the body is in many ways a unit of time, right, with different things that arrive at different points in time, that this human brain is incredibly recent, right, and that my digestive system is incredibly ancient.

These Eves are meant to give us a way into where these features of our bodies might have come from and how that story still shapes how we live in them today.

Jeffrey Brown: For Bohannon, whose Ph.D. research was in cognitive psychology and literature, a fundamental problem, an example of how hominins and early humans learned to problem-solve, is in childbirth.

You say we're one of the worst. We are terrible at it.

Cat Bohannon: Oh, yes. Yes.

Jeffrey Brown: And yet, yes, we populate the globe.

Cat Bohannon: Absolutely. And we do that by having behavioral work-arounds, which is that deep human story. It's kind of what we're always doing. We're always finding behavioral work-arounds for the limitations of our body.

Jeffrey Brown: She took us a long way back.

Cat Bohannon: How you doing, Luce? How's it hanging?

Jeffrey Brown: To Lucy, the version of her on display. All bones here are actually casts. The actual Lucy of the species Australopithecus afarensis was discovered in present day Ethiopia in 1967.

Bohannon's focus, Lucy's pelvis.

Cat Bohannon: The pelvic opening has narrowed, which is part of what enables us to be up here, instead of down here.

And some really, really good scientists have determined that she had a similar problem as we do. She had the obstetric dilemma. She had big babies and had a hard time getting out of, well, a small pelvic opening.

Jeffrey Brown: Right, which a lot of women will relate to.

Cat Bohannon: Yes, I did that twice. I'm good.

Yes. So, but the thing is that means that story, the it-being-hard story, starts at least 3.2 million years ago. And the current theory is that actually Lucy probably had a midwife.

Jeffrey Brown: Lucy had a midwife?

Cat Bohannon: Lucy had a midwife. She was small. She was furry. She was very chimpy. But she had a midwife, because she had difficult births that needed help, and in that moment of vulnerability, to get them out. Yes. Yes, yes, yes.

And that's a big part of our success story, which we don't normally talk about, but yes.

Jeffrey Brown: Bohannon loves that famous first scene of Stanley Kubrick's "2001: A Space Odyssey." But she wants us to focus less on conflict, more on gynecology, and how a focus on evolution of the female body can change how we think of the development of other traits, such as language.

Cat Bohannon: We assume there are these grand moments where language arrives, usually about hunting, shouting directions across...

Jeffrey Brown: Yes, of course. Isn't that the standard story about...

Cat Bohannon: It's a common story.

Jeffrey Brown: OK.

Cat Bohannon: It's a common story.

But remember that all of these are language users, because all of these communicate, all of these mixed-sex members of a group. And when you look at the evolution of language in terms of its developmental path, it becomes a childhood story very quickly. And, frankly, most of the time that's happening with the mother, in part because breast-feeding.

This is when -- you're connected, literally connected, many hours a day to a face which is communicating with you at those critical moments of brain development.

Jeffrey Brown: Bohannon's book, which synthesizes the work of hundreds of scientists, many of them women, raises numerous such examples.

But it also raises critical implications for women's health today and addresses the so-called male norm that has traditionally guided medical science.

Cat Bohannon: That, for a very long time in biology and in biomedical research, we're mostly studying male subjects. That's how we control for estrus, the messiness of that hormonal cycle, was just taking them literally out of the equation.

And we're only just starting to finally rectify that. This is kind of a paradigm shift, kind of a sea change. And we don't entirely know what biological sex differences are going to deeply matter, yet we will know the more we study it.

Jeffrey Brown: We still don't know?

Cat Bohannon: Absolutely not, but excellent scientists all around the world are doing that work right now, which is why this book can even exist.

Jeffrey Brown: She points to the growing awareness of different responses by men and women to opioids, for example, and the need for better guidelines to distinguish between them.

Cat Bohannon: Because we live in the bodies we do that have this deep evolutionary time, our health is affected by how well we understand that history.

Our medicine is shaped by how well we're able to incorporate better knowledge about literally what these things are. And what we are is made of where we came from, because that's how evolution works.

Jeffrey Brown: Deep time down to the present day in a still-developing story of evolution.

For the "PBS NewsHour," I'm Jeffrey Brown at the American Museum of Natural History in New York.