Zener Cards
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.
There are 5 symbols, the star, circle, square, plus and wavy lines. I believe that’s the order they show up in the movie too. So that’s five symbols and five copies of each for a total of 25 cards in a deck. Too bad the gal in the movie didn’t know that, or she wouldn’t have bothered guessing “figure eight.”
The finished design.
The test that the cards were originally designed for was meant to test for ESP ability. One guy holds the card toward him and mentally tries to project the image in his mind. There’s another person sitting opposite who cannot see the card, but tries to receive the mental image. The test isn’t designed to tell if the sender is telepathic or the receiver is clairvoyant, but instead just validate the existence of ESP ability. A book was written by J.B. Rhine in the 30′s stating that after 90 thousand runs of this test ESP ability did in fact exist.
Since these are all basic shapes, the design didn’t take more than a few minutes. Probably the most time was spent on the wavy lines. How wavy should they be? How many humps? How thick? Anyway this is what I came up with.
