Though humans’ nearly hairless bodies stick out like a cowlick among other primates, our nakedness isn’t unique in the world of mammals. Tina Lasisi, a biological anthropologist at the University of Southern California in Los Angeles, said that dolphins and whales are completely naked. There are naked mole rats. “Elephants, depending on how you look at them, are kind of naked,” she says. “But we’re the only weirdos that are naked except for our head.”
The evolution of sweat glands has allowed us to regulate body heat more efficiently, so we traded off a lot of our body hair. What about another unique human trait? We’re the only animals known to express tightly curled hair, like that seen in many people of African descent. Lasisi would like to know the reason and how it happened.
Backstory
Lasisi says that for decades traits that are associated with different racial classes, such skin color and hair texture, were neglected or not studied by anthropologists. Much of the study of human biological variation was deserted after the post–World War II backlash against eugenics, a racist field birthed from the idea that humankind could be improved if those deemed to have desirable traits were selectively allowed to reproduce. Research on human genetic variation has largely remained untouched since then. This includes adaptations to high elevations and lactose intolerance.
But studying all forms of human variation is crucial to understanding our species’s evolution, Lasisi says. Studying variation in a way that normalizes rather than dampens or paints differences in a bad light is key not only to righting anthropology’s harmful legacy, but also ethical, socially responsible and sound science, she says.
Lasisi studied biological anthropology at Cambridge University as an undergraduate student. She was a Black person who grew up among white people in the Netherlands. This made her very aware of skin colors. She vividly remembers learning that human skin pigmentation evolved as an adaptation to ultraviolet radiation — research pioneered by anthropologist Nina Jablonski of Penn State, who would later become Lasisi’s primary adviser. “It’s like a lightbulb went off in my head,” Lasisi says, and it made her wonder, “What else out there can be explained by evolution?”
In part, her interest in curly hair’s origins grew out of a desire to understand her own hair. “Research is me-search,” Lasisi says. But when she first began, there wasn’t much science to comb through, and methodologies for measuring hair texture were either unreliable or inefficient.
Standout research
Lasisi was part of her Ph.D. research and worked with a team that included anthropologists, thermal engineers, and physiologists to examine how curly hair may have given our bipedal ancestors an advantage in the hot, dry African Savanna.
The team tested heat transfer in various environments by placing a variety of human hair wigs onto heat-sensing machines. In dry environments, curly hair, especially those that are tightly curled, was more effective at protecting the scalp against solar radiation than straight hair. It also released more heat to the head than straight hair. Lasisi suggests that curly hair’s larger air spaces are what makes it work.
Lasisi is a supporter of future hair research and to underpin her efforts. A standardized method for measuring hair curvature, cross-sectional and other measurements has been created.The process involves taking photographs of the hair strands, then segmenting them and washing them. Finally, she will run the images through an open source computer program.
She argues that measuring these characteristics along a continuous spectrum (much as we do height) is better than the long-standing practice to classify hair into distinct categories such as straight, curly, or wavy. These categories are subjective and not well-defined by experts. They also obscure the immense variation that exists, even on a single person’s head, and especially among curly hair.
Lasisi is doing highly technical work that hasn’t been part of the conversation, says Robin Nelson, a biological anthropologist at Arizona State University in Tempe. “Before Tina, very few people were working on hair texture in the same way.”
Lasisi will bring this experience to the University of Michigan in Ann Arbor as an assistant professor in 2023, where she’ll continue her studies on human variation.
Reaching out
Lasisi believes everyone should be included in discussions about the human condition. She has also appeared on the podcast. Jonathan Van Ness, Getting Curious (of Queer Eye fame). A PBS digital program on human evolution biology, hosted by her, is also available. Why am I like this?She also helps with the conception and writing of
What’s more, Lasisi has cultivated a community of curious science seekers on Twitter, Instagram and TikTok. Through short-form videos marked by her signature wit and humor, such as her “Melanin March” series or “Darwin’s greatest hits against white supremacy,” Lasisi educates thousands of followers on human variation, how to talk about race and ethnicity from an anthropological perspective, and much more. She also offers career advice and behind-the scenes glimpses into academia for prospective anthropologists. Two-way discussions let her learn from her audience, which she calls her “little focus groups.”
Lasisi hopes her research and outreach will inspire and provide a helpful framework for more nuanced discussions about race, ethnicity, ancestry and human diversity — and that her visibility as a Black anthropologist will encourage other people of color to ask questions that are important to them. “I want to put enough information out there in the world, and [have] enough people out there in the world who have a grasp of that information,” she says, “so that we can see human variation for the beautiful, magnificent, complex thing that it is.”
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