LYNN NEARY, host:
Skin. From the sweet-smelling oh-so-soft skin of a baby to the well-worn tough-to-the-touch skin of an old man, it's the organ we show to the world. No wonder so many fuss about it as we age, spending millions of dollars on Botox injections, face-lifts and skincare products, hoping against hope to fend off those inevitable wrinkles.
Skin, says anthropologist Nina Jablonski, tells us a lot about who we are and what we think about ourselves. Jablonski is the author of "Skin: A Natural History," and she joins us from the studios of member station WPSU in State College, Pennsylvania. Welcome to the program.
Ms. NINA JABLONSKI (Anthropologist): Thank you very much.
NEARY: And let's begin with what I just said in the introduction, that skin is an organ. I don't think most of us really think of it that way.
Ms. JABLONSKI: Well, skin, like the rest of the body, is pretty much taken for granted. It's the biggest organ of the body. It covers a huge amount of our landscape and it does an enormous amount for us, in terms of protecting us from the environment, communicating with our environment and with each other, and it is a cultural canvas by which we communicate to one another.
NEARY: It's also incredibly sensitive. And I would like you to read a short excerpt from your book, where you write about the sensitivity of the skin. The excerpt is in the introduction. It's at the top of page two.
Ms. JABLONSKI: Skin is the interface through which we touch one another and sense much of our environment. Through our skin we feel the smooth cold of melting ice, the warm and gentle breeze of a summer evening, the annoying pinch of an insect bite, the humbling pain of a scraped knee, the soft and calming feel of a mother's hand, and the thrill of a lover's touch.
NEARY: Now, you say there are several things that make skin unique. What are those things?
Ms. JABLONSKI: There are three major ways in which it's unique. The first is that it is mostly naked and sweaty. We have very little body hair compared to other animals and we sweat a great deal to keep us cool. It also comes in a natural range of beautiful colors, and these colors have been forged by the forces of evolution.
And then the third unique aspect of human skin is that it's a way that we can advertise ourselves. People put cosmetics, body paint on the skin. Or they affix more permanent decorations like tattoos or piercings or other brands to their skin. And so it is a very, very complex organ of communication.
NEARY: Well, how did our skin become naked and sweaty?
Ms. JABLONSKI: Well, probably around two million years ago our skin went from being sort of hairy and animal-like to being mostly naked and having very, very little body hair. And this was clearly related to a very important transition that we made in our evolutionary history, from being more or less ape-like, being relatively close to trees and walking relatively short distances, to being extremely energetic bipedal humans, walking and even running in a very hot equatorial environment.
In order for us to keep cool under these conditions we really needed to have a body that was mostly free of body hair so that we could keep ourselves cool through sweating. And humans are the sweatiest of all primates.
NEARY: When or how did differences in skin color emerge?
Ms. JABLONSKI: Of course you can imagine, here are our ancestors in equatorial Africa with naked skin being exposed to the greatest intensity of solar radiation, especially the damaging rays of ultraviolet radiation. And we at that time became very deeply pigmented. And that dark pigment is a natural sunscreen that protects beautifully against the damaging ultraviolet rays of the sun.
But humans didn't stick in equatorial Africa. They began to disperse outside of Africa just a little less than two million years ago. And as they went into less sunny climes, there was considerably less ultraviolet radiation, and they actually began to actively lose pigment in their skin.
NEARY: Now did people always use skin for decoration? Was that just kind of just an instinctual thing?
Ms. JABLONSKI: Well, you know, it's hard to know how long people have been using skin as a palette. We have indications from the use of red ochre, existing over 70,000 years ago, from a cave site in South Africa. Now, red ochre is a well-known, almost universally known, body paint. Were these people etching the red ochre for use on their own bodies? We don't know. We never or very rarely find skin preserved for more than a few thousand years.
But certainly we know that people have been doing this for a very long time.
NEARY: And it's interesting that tattooing, body piercing, all of this is certainly experiencing a revival in Western culture, in our own country right now.
Ms. JABLONSKI: Tremendous. This is something that humans have a penchant for doing, but there is a tremendous array of body art that is now available to people should they choose to get it.
NEARY: What about the incredible array of skin products out there and the current sort of trend to use things like Botox and plastic surgery to try and keep skin looking young?
Ms. JABLONSKI: Well, the idea of looking perennially youthful, having basically a young person's skin, is becoming more and more important. This is strange to me because although primates as a group do judge individuals by their appearance, they also judge individuals by the content of their character, as it were.
So this trend toward perennial juvenation of the skin seems to be a bizarre cultural fixation that dwells on the importance of the first impression.
NEARY: I think it's interesting that the photograph you've chosen for the cover of your book is not a photograph of a baby's skin or a beautiful woman's skin. It is a photograph of a very wrinkled arm, and it's almost one of those kinds of images that you can't stop looking at.
Ms. JABLONSKI: That is why I chose it, because I wanted to make the point in this book that the skin is a biography. And when you look at the picture of that Tibetan woman's arm, you can't see her face, but you know that she's an older woman, that she's had a lot of sun exposure, probably quite a hard life, because she has some scars on her arm. That is skin that tells a story.
NEARY: Nina Jablonski is a professor of anthropology at Pennsylvania State University and the author of "Skin: A Natural History." She spoke to use from member station WPSU in State College.