Great apes deliberately spin around in order to make themselves dizzy, researchers have discovered. Academics at the University of Warwick and the University of Birmingham suggest the findings could provide clues about humans evolving the desire to seek altered mental states and actively manipulate their mood and perception of reality. The study is based on observations of online videos in which great apes – gorillas, chimpanzees, bonobos and orangutans – spin to deliberately make themselves dizzy.