Extrasensory perception (commonly abbreviated ESP, and colloquially known as a "sixth sense") is the term used to describe claimed reception of information through means other than the recognised physical senses. It functions as an umbrella term on The Vault, gathering together Telepathy, Clairvoyance, Precognition, and retrocognition — the claimed ability to perceive past events rather than future ones — as distinct manifestations of the same underlying claimed capacity. This page covers the term itself, its scope, and how it has been approached scientifically; for the general claimed abilities it refers to, see Psychic Ability.
Note: the term was originally hyphenated as "extra-sensory perception" — the spelling used in Rhine's original 1934 book title — but the unhyphenated form is now standard in general and academic use, and is used throughout this page accordingly.
Scope
ESP is generally treated as covering four related claims:
- Telepathy — direct perception of another person's thoughts or feelings
- Clairvoyance — perception of an object, place, or event beyond the ordinary senses
- Precognition — perception of a future event
- Retrocognition — the claimed mirror-image ability to perceive a past event, without any ordinary means of knowing it
Mediumship is treated separately on The Vault, since it specifically concerns communication with the dead rather than any of the four claims above, though the two are frequently discussed alongside each other in practice.
Origin and adoption of the term
The term is most closely associated with parapsychologist J. B. Rhine and his 1934 monograph Extra-Sensory Perception — published, and spelled, with the original hyphen, per its actual title — issued by the Boston Society for Psychic Research. Sources differ on whether Rhine coined the phrase outright or adapted it from earlier usage by Frederic Myers, who had coined "telepathy" decades before. Rhine's choice of the term over older ones like "clairvoyance" and "telepathy" reflected a broader effort to align psychical claims with the language of experimental psychology, rather than with 19th-century Spiritualism.
Testing methods
Two broad experimental traditions have dominated ESP research:
Forced-choice testing presents a subject with a small, fixed set of options — most famously Zener cards, a deck of five symbols developed for Rhine's early Duke University experiments — and measures whether their "hit rate" exceeds what chance alone would predict.
Free-response testing allows a subject to describe impressions in their own words rather than choosing from fixed options, the approach used in the ganzfeld experiments developed at Maimonides Medical Center in the 1970s. Free-response methods were developed partly in response to the view that memory, rather than raw perception, might be a better model for how "psi" (a term used interchangeably with ESP in much of the later literature) actually operates.
Both traditions were carried forward at the Koestler Parapsychology Unit at the University of Edinburgh, established in 1985, where parapsychologist Charles Honorton continued automated ganzfeld work from 1991 until his death shortly afterward, in collaboration with psychologist Daryl Bem — the same researcher behind the later, widely disputed 2011 "Feeling the Future" precognition studies.
Scientific reception
Mainstream science has never accepted ESP as an established phenomenon. Early large-scale replication attempts, including a 1936 Princeton study of over 25,000 trials, failed to reproduce Rhine's reported results, and psychologist Joseph Jastrow argued as early as 1938 that much of the supporting evidence collected by Rhine and others was anecdotal and methodologically weak. This pattern — promising early results followed by inconsistent or failed replication — recurs across ESP's experimental history and is discussed in more detail on the individual pages for Telepathy, Clairvoyance, and Precognition.
Cultural use of the term
Despite its retreat from mainstream academic vocabulary in favour of "psi," "ESP" remains the dominant term in general public and popular-culture usage for claimed extrasensory ability, considerably outliving its original, narrower scientific definition.
See also
- Psychic Ability
- Telepathy, Clairvoyance, and Precognition
- Mediumship
- Parapsychology
- Extra-Sensory Perception (1934 book)
- J. B. Rhine
- Society for Psychical Research
- Koestler Parapsychology Unit
- Daryl Bem