Extrasensory Perception
(ESP)
Lecture 7
Parapsychology
Paul Staples
Overview
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What is ESP?
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Experimental evidence
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Telepathy
Clairvoyance
Precognition and Retrocognition
Restricted-choice experiments
Free-response experiments
The process approach
 Summary
Learning Objectives
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This session will enable you to
 Give a reasonable definition of ESP
 Categorise the various types of ESP
 Understand the nature of the experimental evidence
available
 Appreciate the criticisms and counter-criticisms of
some of the findings
 Appreciate the difference between resticted-choice
and free-response scenarios
 Recognise that there are other considerations, such as
those suggested by the process approach
What is ESP?
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Extrasensory perception (ESP) is perception
that occurs independently of the main physical
senses (sight, hearing, touch, taste and smell
or, indeed, perceptual processes such as
proprioception)
 In some ways the term is vague but it is
generally used to imply a source of information
that is unknown to modern science
 ESP can be divided into a number of subcategories
Telepathy
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For telepathy the source of information is
another person’s mind
 The principle requirement of telepathic
transmission is that the information transfer
cannot be explained by any known physical
process
 Often the demonstration involves information
transfer over large distances
 Unlike physical information transfer, telepathy
is not subject to the weakening of the signal
the further you move away from the source
Clairvoyance
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Clairvoyance is similar to telepathy except that
the source of the information is an object or
event rather than another mind
 As well as clairvoyance, we can propose
clairaudience where the source of information
is auditory rather than visual
 Clairaudience is an alleged psychic ability to
hear things that are beyond the range of the
ordinary power of hearing, such as voices or
messages from the dead
Precognition and retrocognition
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If the clairvoyance or clairaudience concerns things in
the future or the past the these are referred to as
precognition and retrocognition respectively
Dreams have sometimes been related to precognition
and characters like Nostradamus are famous for their
precognitive visions
Retrocognitions can be about recent events (e.g. the
perpetrator of a recent murder) or distant events (e.g.
historic events)
Retrocognition is different from past life regression
Experimental evidence
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ESP experiments fall into two broad categories
Restricted-choice experiments
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The receiver must make a decision about what is being
transmitted from a small set of known possibilities
Zener cards are an example of restricted choice stimuli
Free-response experiments
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Here the sender will choose an item from a large but finite set
of possible stimuli
The receiver is not told anything about the nature of the
chosen stimulus
The remote viewing you participated in was a free-response
set up.
Restricted-choice experiments
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In the 1930s one of the most prominent places
for ESP research was the Rhine laboratory in
America established by J B Rhine
A typical study from that era is the PearcePratt experiment
Typical card-guessing experiment – using
zener decks (25 cards, 5 target alternatives,
MCE = 5)
74 runs conducted over 37 sessions
Sender and receiver (Pratt and Pearce) in
separate buildings (100 or 250 yards apart)
Restricted-choice experiments
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Watches synchronised so that when Pratt
turned over a card, Pearce made a guess
Both recorded their sequences
Hits counted independently by Rhine
Rhine present with Pratt during last few
sessions
Mean hits per run was significant at p < 10-22
No likelihood that results were due to chance
Restricted-choice experiments
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Hansel (1961) criticised the study by
suggesting that as no-one was with Pearce
during the sessions, he could have gone out of
his room and looked through a window at
Pratt’s cards.
 This could not be shown to be wrong until
1967 when Stevenson was able to locate the
original blueprints
 However, on scrutinising the official and
unofficial reports of the experiments there are
inconsistencies in the number of hits recorded
Restricted-choice experiments
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Pratt-Woodruff experiment (1939)
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2,400 runs across 32 volunteers
Mean hit rate was 5.21, p < 0.00001
However, the result attributable to only 5 of the 32
volunteers
Pavel Stepanek
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Library clerk from Czechoslovakia
Took part in 27 studies across 18 investigators
Was discovered through his ability to state whether
the white or dark side of a thin piece of cardboard
was face up inside an opaque envelope
Performance level at around 57% correct, p<10-6
Restricted-choice experiments
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Bill Delmore
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Yale law student in the early 1970s
Unusual in that he had vivid visual imagery, frequent lucid
dreams (knowing you are dreaming) and a high degree of
confidence in his psi abilities
520 playing cards mixed and placed in desk drawers
Experimenter picked a card and without looking at it placed it
in an opaque folder
46 runs of 52 trials each (2392 trials)
Delmore had an excess of exact hits! For exact hits p < 10-30
Delmore was also successful on other tasks
Free-response experiments
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Remote viewing (RV) experiments
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Puthoff and Targ were the first to do this in the late 1970s
They worked with Uri Geller whom most parapsychologists
quickly became suspicious of
Their first work was with Pat Price, a Californian police
commissioner
Target location chosen from a pool of 100
Target observed for 30 minutes
Price asked to verbally describe and to draw the location
Nine trials
Independent judge taken to each site and then asked to rank
the drawings from 1 to 9 according to their similarity to the site
Seven were ranked first at the correct site (p < 10-4)
Free-response experiments
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Critics of these experiments are Marks and Kammann
(1980)
They suggested that there were biasing clues in the
transcripts of the verbal descriptions
Now some of the judges failed to correctly identify
matches
Also, only the most successful trials were chosen for
publication and this falsely increased the statistical
result
However, there have been a number of successful RV
experiments reported in the literature
Free-response experiments
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Ganzfeld Experiments
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We have already talked about the Ganzfeld
procedure
It has become a popular method of testing ESP
Honorton (1978) claimed that 23 out of 42 ganzfeld
experiments had yielded statistically significant
results
Successful results came from 9 independent labs
Taken as a collection of results the evidence seems
quite impressive
Free-response experiments
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In the 1980s, Hyman criticised the findings on several
grounds
Experiments had small numbers of participants and
may only have been submitted for publication if the
data were significant
Scoring procedures varied widely across the studies
In experiments using multiple conditions only one had
to be successful for a positive claim to be made
One-tailed tests were used even though psi-missing
outcomes (the other tail) were considered as
successes (i.e. a success was recorded for a score
significantly different from chance whether it be better
or worse than chance)
Free-response experiments
Honorton countered these criticisms by
recalculating the results in line with the
criticisms
 The level of success was not
compromised even though the success
rates reported had been too high
 Other criticisms, such as one concerning
the quality of the randomisation process,
were conceded by Honorton
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Free-response experiments
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Overall, it would seem that the studies have
been fairly rigorous even though
improvements could have been made
 However, this is no more true here than it is in
all other areas of human research
 Whilst the apparent ESP demonstrated so far
may not compel one to accept ESP, the
evidence does point to there being something
worth further investigation
The process approach
All of the research considered so far is
concerned with trying to establish proof
of the existence of ESP
 Other research tries to increase our
understanding of psi anomalies
 Some may consider this approach
premature until the proof has been
verified
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The process approach
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The process approach looks at the following aspects
that need to be considered
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Cognitive processes – right hemisphere, cognitive capacity.
Belief in ESP – sheep and goats
Personality traits – extraversion/ESP correlation
The experimenter effect – experimenters get significant
results in psi experiments because of…experimenter error,
psychology and psi hypotheses.
It attempts to explore the degree to which these
factors interact with ESP
 There is not time to explore these aspects further here
Summary
We have seen that there is some
convincing data concerning the possible
existence of ESP
 The data are not yet at the stage where
they provide unequivocal proof of the
existence of ESP
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