CHRISTOPHER CHABRIS and DANIEL SIMONS are cognitive psychologists who have each received accolades for their research on a wide range of topics. Their “Gorillas in Our Midst” study reveals the dark side of our ability to pay attention and has quickly become one of the best-known experiments in all of psychology; it inspired a stage play and was even discussed by characters on C.S.I. Chabris, who received his Ph.D. from Harvard, is a psychology professor at Union College in New York. Simons, who received his Ph.D. from Cornell, is a psychology professor at the University of Illinois.