decorative image
Bryn Mawr College home page
  Alumnae Bulletin  
  Alumnae Association  
 Admissions Academics Campus Life News and Events Visit Find

By Tom Durso

The comedian Stephen Colbert isn’t a toxic, right-wing talk-show host, but he plays one on TV. And so when Nina Jablonski ’75 appeared on The Colbert Report, Comedy Central’s brilliant O’Reilly Factor send-up, to chat about her new book, Skin: A Natural History, the faux fireworks that followed were no surprise.

Jablonski, who chairs the anthropology department at Penn State, was asked by Colbert why a natural history of skin was needed, since “we all have it.”

“Well, we all have it,” Jablonski acknowledged, “but there isn’t a book that really tells us how skin evolved.”

Ever in character, Colbert jumped right in: “Well, skin didn’t evolve. God gave Adam and Eve skin, and Adam and Eve gave skin to their children, Cain and Abel, then Cain killed Abel, and that’s how we got different races.”

“I think you really have to embrace your evolutionary history,” a clearly amused Jablonski replied.

“I don’t think I do. Okay?” Colbert said. “You’re not going to say monkey or anything, are you?”

“No,” Jablonski answered, “but I may say ape.”

“You may say ape,” the host mused, his audience laughing. “Well, go ahead, say it. We’ll just bleep it.”

She did. And they did.

Skin color and reproductive success

In her book, Jablonski offers a comprehensive overview of the body’s largest organ, covering such topics as its structure and history, sweat, body art, and its role in emotions and sex. Perhaps Skin’s most provocative passages deal with the evolutionary aspects of skin color. According to Jablonski’s research, the various shades of humanity across the globe are not racial characteristics or markers but adaptations to sunlight and how close our ancestors lived to the equator. Around the same time they lost most of their body hair, early humans had to develop melanin in their skin to protect them from ultraviolet radiation, which damages the B-vitamin folate needed for DNA and cell division. When people migrated away from the equator and toward the poles, where rays from the sun are less direct, they needed to absorb more sunlight to make vitamin D, which is also important for health and reproductive success, and so lighter skin evolved to foster that process.

“Light skin evolved more than once in human history,
in Western Europe and in East Asia,” says Jablonski. “Dark
skin re-evolved once and perhaps twice in populations dispersing into Melanesia and the southernmost part of the Indian subcontinent.”

Such evolution is unlikely to occur again, she adds, because humans have found ways to adapt to vast changes
in sunlight.

“It is unlikely that major changes in pigmentation will occur in the future, except through population admixture,” Jablonski says. “This is because we are so very good at buffering ourselves against the exigencies of our physical environment through culture. We wear clothes, hats, sunscreen. We use various kinds of shelters. We alter our diet, etc. All of the evolutionary pressures that are placed upon us are met with a cultural, not a biological, solution.”

Evolution and racial identity

Colbert’s hyper-exaggerated reaction aside, evolution and racial identity are among our most culturally explosive topics, capable of stirring up immediate and passionate responses across the political spectrum.

“When I was in graduate school,” Jablonski recalls, “people said, ‘Don’t even think of working on something like skin color, because it’s so socially charged, so difficult, so fraught. No matter what you say, you’ll be criticized.’ ”

But a funny thing happened to Jablonski on her way to the metaphorical gallows. Instead of becoming a social pariah, she was unexpectedly welcomed.

“People notice things about one another,” she says. “They notice human variation in biology and want to know why it exists. Most people want the straight story. They want to know why they have the skin color they do. I have found that people have an almost insatiable curiosity about this....One of the most important things about talking about human anatomy and human variation is it’s all about how you say it. When you speak in a matter-of-fact way and dispassionately about the way people look and the best evolutionary scenarios we have for how these appearances evolve, it’s like, ‘Oh, wow, golly, that’s really interesting.’ ”

Jablonski says that in years of lecturing on skin color evolution before her book was published, and in the talks she’s given since then, just one person has approached her to accuse her of racism simply for studying the topic.

“My feeling is that if one is keenly aware of how these things need to be talked about in modern society, and if you work deliberately to talk about them using nonpejorative vocabulary in a dispassionate way, people welcome these discussions,” she says. “They welcome the information because it helps them to understand their own appearance and why somebody looks different from them. They think, ‘This might have some health implications for me’ and ‘That’s why my ancestors may have suffered some prejudice or been prejudiced against others.’ It helps people understand a huge amount of their own biology and their own social motivation. And at the end of the day, most people want to learn. That’s what I have been continually amazed at. Over the years and months, the audiences have gotten bigger, and yet I’ve gotten so little negative feedback I can put it in a thimble.”

Where we need to do better as a society, Jablonski notes, is in public education, which she faults for “failing adequately to teach logical thinking and inquiry, and to provide effective basic science education, especially in the last 20 years. Sadly, many people don’t want to learn more about science or evolution. This is partly because many of them find that all this kind of knowledge is too threatening to them, and their own feeling of their place in the world.”

Serendiptious science

Jablonski’s ability to connect with an audience, present theories and knowledge in nonthreatening ways, and defuse what are often incendiary conversations can be traced, perhaps, to an eclectic scientific background that allows her to converse easily about a variety of topics to a variety of people. Her bachelor’s degree from Bryn Mawr is in biology, while her doctorate, from the University of Washington, is in anthropology, with her dissertation exploring the “masticatory apparatus” of the Gelada Baboon. Her research specialties are primate evolution and the evolution of how humans began to stand and walk on two legs. She has conducted paleonto­logical fieldwork—digging for fossils—in China, Kenya, and Nepal, been a researcher at the California Academy of Sciences, and taught in Hong Kong and Australia in addition to Penn State.

“I put together a lot of observations that people hadn’t before put together,” she says of the breakthroughs described in Skin and the papers she’s written. “There’s so much of science that’s about being in the right place at the right time. It’s not like you’re sitting there like Isaac Newton coming up with new principles on how the universe works. What you’re doing is tapping into lots of different information and putting it together. One of the things I have going for me is that I am an extremely eclectic reader and a vast consumer of a variety of scientific information. For me to conduct any studies on human and primate evolution, I have to think about scientific investigations and a breadth of discoveries in many different fields. If I don’t keep up to date in many different fields, from geology to medicine, I fall behind in the way I can do my science. I’ve always been a very catholic, eclectic consumer of scientific information and as a result I’ve been able to come up with syntheses that are unique and that are new to science.

“Many scientists work by drilling deeply into one small area. Others are like me—the scavenger model,” Jablonski adds. “What can I determine from different discoveries that shed light on a problem? The stuff I bring out in my book and papers was building on observations often done in a different context, but clearly the phenomenon could be related to the problem I was studying.”

Jablonski talked about the benefits and potential import­ance of such eclecticism in a lecture at the College last winter.

“If you ever have an adviser trying to get you to narrow and refine your interests, it’s important to pay attention to them, because they want you to succeed in one area,” she told students, “but if your heart inclines you to any different areas of research, don’t go away from that, because often you can
find yourself happening on discoveries if you go in unexpected, personal scientific directions.”

According to Jablonski, analytical techniques have become sufficiently streamlined to allow for relatively easy mastery, allowing scientists more freedom to explore interests beyond their specialties.

“In science there’s the emphasis on training in one small area,” she says. “I don’t want to tell students they should just be some esoteric dabbler, but you can specialize in one area and still be a broadly read and broadly interested scientist. Many of my colleagues with whom I work and most admire are people who have very specific areas of expertise but broad bases, and in some cases even a few different areas of expertise that are quite different from one another. ... Don’t be shy about reading widely. Indulge that. You will almost certainly, through acci­dental reading, through genuine serendipity, come across stuff that relates to a problem that you have had for a long time. You can be reinforced in being a broad scholar. You make your own luck, constantly survey the scene, see what’s out there.”

Nina Jablonski ’75 shows Bryn Mawr lecture audience the most commonly reproduced map of human skin color, composed by Italian geographer Renato Biasutti and published in 1959. New data have allowed Jablonski and her husband and colleague, geographer George Chaplin, to create a more accurate map, although both show the trend of darker skin closer to the equator and lighter closer to the poles. Until the 1950s, anthropologists and clinicians used the equivalent of paint chips to assay color on the unexposed skin of the upper inner arm site. Now they measure the amount of a given wavelength reflected from the surface of the skin. “We talk about skin reflectant as opposed to skin color, properly speaking,” says Jablonski.


What’s out there these days is Jablonski herself. Her Colbert Report appearance was preceded by a Q&A in the New York Times (January 9, 2007), and her provocative yet logical thesis on the evolution of skin color has earned her admiration among online observers and live audiences alike, no mean feat in an era when snide, anonymous commentary seems to carry the day.

“I hold out some optimism for humans,” she says cheerily. “When people take time to think deeply about [an issue] and can see a rational explanation, they say, ‘Okay, fine. Next pro­blem.’ People want these kinds of questions answered. In the case of skin color, people have noticed it but never talked about it because it’s such a socially prohibited topic. When somebody does talk about it, it relieves this pressure on them—they say, ‘Wow, this is just interesting. This isn’t some weird kind of odd thing we have to conceal. It’s just an interesting evolutionary story. Let’s talk about it.’”

One gets the feeling Stephen Colbert couldn’t agree more.

Tom Durso is a freelance writer based in the Philadelphia suburbs. The March 29, 2007, Colbert Report with Nina Jablonski ’75 may be viewed at



Return to May 2007 Highlights





Bryn Mawr College · 101 North Merion Ave · Bryn Mawr · PA · 19010-2899 · Tel 610-526-5000