The Scientist | Duke University Archives
DIVINING AN ANSWER: J.B. Rhine’s early experiments at Duke University employed a set of cards named “the Zener deck” after its inventor, Karl Zener, one of Rhine’s collaborators. The deck consists of 25 cards, with five of each symbol: square, circle, cross, squiggly lines, and star. Here, Rhine is shown testing a woman for ESP using the cards in the presence of an assistant (right).