Under the skin

The genetics and natural history of human pigmentation

In the 2004 satirical South Park episode “Goobacks,” humans from a poor, overcrowded future time travel to the present, and begin to compete with native Coloradans for jobs. The episode is notable for its durable memes about a working-class fixation on “muh jerbs.” But it also reflects a widespread vision of the future of humanity. The refugees looked very similar to each other, all with a skin of a light red-brown shade. After hundreds of generations of racial intermarriage, the presumption is that salient physical differences will have disappeared through blending, producing a uniform and homogenous future population. This view is even anticipated in the shorter term in mainstream US media, with phrases such as “the browning of America” cropping up in the public discourse.

This idea’s roots go back to the 19th and 20th centuries, due to eugenic concerns on the part of white Europeans and Americans about the integrity of their race. Racist works like Lothrop Stoddard’s The Rising Tide of Color Against White World-Supremacy reflected an alarmist fear of being swamped out and assimilated. A world of white supremacy giving way to monotonous brownness. Today this beige future is viewed more positively. But both visions are rooted in the simple fact that skin color is the most socially significant marker of human identity after sex. Skin is the largest organ, and our complexions signal both age and health. Our species cares a great deal about what skin looks like for evolutionarily significant reasons. But skin color has also become wrapped up in fraught dynamics in recent epochs of world history. Dr. Martin Luther King Jr. famously hoped his children would not be judged by “the color of their skin.” Whereas in Europe ethnic distinctions are rooted in history, and reflect nuances of language, nationality and geography, like the difference between the French and Germans, in America the two traditionally dominant racial groups are denoted starkly by skin color, white and black.