
Do you remember that scene at the beginning of Ghostbusters when Dr. Peter Venkman is conducting his research on “the effect of negative reinforcement on ESP ability?” If you don’t its a classic, go rent it. Basically Bill Murray holds up what look like large playing cards with different designs on them, and people try to guess what the design is. They’re called Zener Cards and they were created by Karl Zener in the 1930’s for ESP test conducted with J.B. Rhine.




