[[Karl Zener]] was an American psychologist and parapsychologist. He is best known for developing the [[Zener Cards]] in the early 1930s, which became a standard tool for testing [[ESP]] (extrasensory perception) in [[Parapsychology|parapsychological]] experiments. Zener collaborated with [[J. B. Rhine]] at the [[Duke University Parapsychology Laboratory]].[^1] [^1]: Jacobsen, Annie. *Phenomena: The Secret History of the U.S. Government's Investigations into Extrasensory Perception and Psychokinesis*. Little, Brown and Company, 2017.