Zener card guide
Zener cards were designed in the early 1930s by the perceptual psychologist Karl Zener for J. B. Rhine’s card-guessing experiments at Duke University. The five symbols are a circle, a cross, three wavy lines, a square and a five-pointed star.
How trials are drawn here
Each trial’s symbol is drawn independently and uniformly from the five, with replacement, by a cryptographic random generator on the server. It is stored before your guess is accepted. Every trial therefore has the same 1-in-5 chance of a hit, whatever came before.
This is not a simulation of a physical 25-card deck with five of each symbol. In a deck dealt without replacement, the odds change as cards are used up, and a guesser who tracks what has gone can do better than 20%. Deck-based modes are planned separately, with their own documented scoring.
Feedback
- After each guess: the symbol is shown as soon as your guess is recorded.
- At the end: no symbol, and no running score, is shown until the session ends.
Symbols you have not yet been shown never reach your browser.
Reading the score
The result shows hits, the number of trials and the chance baseline: about one hit in every five trials. Chance alone produces runs well above and below 20%, especially over short sessions. Scores here record practice; they are not a measure or proof of psychic ability. Stopped sessions stay in your history with the trials you answered.