Psi Chi (ΨΧ) is the National Honor Society in Psychology, founed in 1929 for the purposes of encouraging, stimulating, and maintaining excellence in scholarship, and advancing the science of psychology. It is one of the largest honor societies in the world, with over 1,050 chapters and 500,000 members in the United States and Canada. Famous members of Psi Chi include B.F. Skinner, Philip Zimbardo, Dr. Phil (Phil McGraw) and Hugh Hefner.