YORK, ENGLAND—According to a report in Vox, evolutionary anthropologist Penny Spikins and anatomist Paul O’Higgins of the University of York and their colleagues think modern humans may have evolved smooth, long foreheads with agile eyebrows as a way to communicate emotions, and thus, enhanced the ability to survive. The researchers created a 3-D computer model of Kabwe I, a Homo heidelbergensis skull, and manipulated it to see whether shaving back its heavy brow ridge affected simulations of chewing meat, or how the brain case and eye sockets fit together. The analysis suggests that reducing the creature’s thick brow ridge would not have caused any functional problems. Spikins and O’Higgins speculate that the brow ridge may have instead served as a social signal of strength and dominance. Larger foreheads and smaller brow bones may have evolved along with more complex muscles for controlling subtle eye and eyebrow movements capable of expressing the modern human state of mind. For more on the evolution of the human face, go to “Your Face: Punching Bag or Spandrel?”