We all know these five curious symbols: the circle, the cross, the waves, the square, and the star, but do you know where they come from?
These symbols are known as ESP symbols, with E.S.P. standing for Extra Sensory Perception. Originally, these cards were grouped into five decks of five cards each, making a total of 25 cards.
Karl Zener
Invented in the 1930s, they were created by Karl Zener, which explains why they are sometimes called Zener cards. Zener wanted these cards to be a real tool for his parapsychology experiments, allowing him to prove – or disprove – the existence of certain powers in individuals who could guess the symbol on a card without seeing it.
These cards were first used in early quantitative research conducted in the field of parapsychology, particularly by Joseph Banks Rhine, one of the first scientists to use statistics to study extra-sensory perception at Duke University in North Carolina.
Joseph Banks Rhine
It is worth noting that while numerous experiments were conducted with these cards, none have yet demonstrated the existence of supernatural powers. In a televised episode of Exploring Psychic Powers Live!, James Randi, a famous magician and skeptical investigator, invited someone who claimed to possess a gift to prove it using Zener cards. 250 cards were presented to him, but the man could only identify 50 correctly, which is a result representative of chance and not significant.
These symbols have subsequently been widely used in magic, particularly in mentalism, in various experiments. While some have created genuine marked decks allowing for the reading of symbols without seeing them, others have written books on the subject, such as Armand Porcell.
These cards also hold a secret that is very useful for magic and allows you to perform an impromptu trick… You ask the spectator to freely choose one of these symbols and draw it on a sheet of paper. You turn your back during this time so you can't see anything… but you can hear! Indeed, if you pay attention, each symbol is drawn with a different number of pen strokes: the circle is drawn with one stroke, the cross with two, the waves with three, the square with four, and the star with many more. From there, you just need to pay attention to the drawing and listen carefully to know the number of strokes made. With this number, it will be easy for you to guess the drawn symbol without ever having seen it… incredible, isn’t it?
Now you know a little more about these curious symbols that we sometimes see in magic tricks…!
