the many species of hominids that preceded us had prominent browridges, but we Homo sapiens gave them up in favor of our small, active eyebrows. It’s not easy to say why. One theory is that eyebrows are there to keep sweat out of the eyes, but what the eyebrows do really well is convey feelings. Think how many messages you can send with a single arched eyebrow, from “I find that hard to believe” to “Watch your step” to “Care to have sex?” One of the reasons the Mona Lisa looks enigmatic is that she has no eyebrows. In
