How the Laughing Cavalier keeps an eye on everybody "From second-rate horror films to episodes of Scooby-Doo, ominous paintings whose staring eyes follow a character around the room, no matter where they go, have been used to spooky effect. But now a team of scientists believe they have solved the mystery of how they do it.
A group working on how our brains interpret images found that as long as a character in a painting is looking straight ahead, our brains will perceive they are staring at us, no matter the angle from which we view the painting. A striking example is The Laughing Cavalier by Frans Hals, the 17th century Dutch painter. "
theguardian
  ¶ 5:44 AM