The Zener Cards

Zener Cards are a set of 25 cards used in experiments to test psychic or extrasensory perception (ESP). Each card has one of five symbols: a circle, a plus sign, three vertical wavy lines, a square, or a star. In testing, one person tries to secretly select a card, while another attempts to guess the symbol based on intuition. The cards help scientists study whether people can perceive information beyond the five senses, though results remain highly debated and inconclusive. Essentially, Zener Cards are a standardized tool for exploring claims of psychic abilities.