For years biologists, anthropologists, and sociologists have all agreed that racial categories are social constructs.  Recently, however, new genetic information about human evolution has required that scientists re-think the biological reality of race.  In this 6-minute video, sociologist Alondra Nelson describes this re-thinking:

Lisa Wade, PhD is a professor at Occidental College. She is the author of American Hookup, a book about college sexual culture, and a textbook about gender. You can follow her on Twitter, Facebook, and Instagram.