Extra sensory perception, referred to as ESP is the ability to sense things that our physical senses do not. Also called the ‘sixth sense’, it encompasses psychic abilities like telepathy, clairvoyance, clairaudience, intuition, remote viewing, psychokinisis, astral projection, retro-cognition, and precognition, among other things.
The study of paranormal psychic phenomena, known as parapsychology, was made popular by J.B. Rhine and his wife Louisa Rhine at Duke University, North Carolina in the 1930’s. The couple used Zener Cards invented by Karl Zener to measure telepathy whilst around the same time a technique invented by Wolfgang Metzger called the ganzfeld experiments are still used today.
Zener Card image from Wikipedia