In the experiment, the volunteers were asked to play a computer game. They believed they were playing two other people, but in fact played a set computer program.
"It looked like a ball being thrown around between the three people," Lieberman said.
Eventually, the game excludes the player. "For the next 45 throws they don't get thrown the ball," Lieberman said.
"It is just heartbreaking to watch. They keep indicating that they are ready to be thrown to.