4. “Psi” phenomena
Thouless (1942), after Wiesner:
Psi = the psychic force thought to be manifested by
the paranormal phenomena that comprise the
subject matter of parapsychology
5. “Psi” phenomena
Thouless (1942), after Wiesner:
Psi = the psychic force thought to be manifested by
the paranormal phenomena that comprise the
subject matter of parapsychology
Generally refers to interaction between the
private mind and the public world
World Mind: Extrasensory perception (ESP)
Telepathy
Clairvoyance
Precognition
Mind World: Psychokinesis (PK)
6. Extrasensory Perception (ESP)
e.g., Ganzfeld (“total field)” experiments
Bem & Honorton (1994)
35% “hit” rate
(vs. expected rate = 25%)
p = .002
Milton & Wiseman (1999)
Failure to replicate
Identified statistical error
in Bem & Honorton’s
analysis
7. Extrasensory Perception (ESP)
e.g., Ganzfeld (“total field)” experiments
Debates over evidence
Replication problem
No reliably replicable
demonstration exists
“Gifted” researchers?
Effect sizes
Inadequate controls
Sensory leakage
Randomization
File-drawer problem
8. Psychokinesis (PK)
Late 19th century: non-experimental research
Anecdotal reports on séances
Case studies, field investigations, etc.
William James (1896)
9. Psychokinesis (PK)
Late 19th century: non-experimental research
Anecdotal reports on séances
Case studies, field investigations, etc.
William James (1896)
1920s onwards: experimental research
e.g., Rhine (1927), Duke University
Dice-throwing studies, of increasing sophistication
Dice-throwing machines
Photographing of throw outcomes
Corrections for weight unevenness
Girden (1962)
Sophistication reduces effect size
to non-significance
10. PK dice studies
Radin & Ferrari (1991) meta-analysis
148 studies from 1935 to 1987
2,569 participants; 2,592,817 dice throws
Small, but statistically significant, overall effect
Effect size moderated by methodological features:
Effect size
statistic (π)*
All studies (148) .50610
All studies, weighting for quality (148) .50362
Studies controlling for dice-weight unevenness (69) .50431
Studies controlling for weight and statistical homogeneity (59) .50158
Studies controlling for weight, homogeneity, and quality (59) .50147
*As computed by Bösch et al. (2006); π = .50 indicates chance levels
11. PK dice studies
Bösch et al. (2006)
Number of unpublished null effects required to explain
Radin & Ferrari’s effect (of π = .50147):
60
12. 1011011011101111
PK RNG studies 0100100111010010
1101001001110011
0010010100111011
1010000011011101
0001011010101101
RNG = “random number generator” 0101010011001100
0100111000111011
Sources: 0010001110011001
0110100011110111
Rhine Research Center Institute for 1010100010000000
Parapsychology (Helmut Schmidt) 1111011010000110
0000100110100010
Princeton Engineering Anomalies 1011011010100100
Research (PEAR) laboratory 0010000101000100
1010111101110100
0001011111000010
RNG produces a random stream of 1101110111010101
1011011001100011
1s and 0s 0000101100000000
0110110010111101
Participant seeks to mentally 0000001110111111
influence RNG to produce more 1s 1000001000111101
0000010101101101
than 0s (or vice versa) 1011101111010010
0111010010110100
1001110011001001
0100111011101000
13. PK RNG studies
Advantages
Automation
Facilitates fully standardised replications
Allows for lots of research
Lots of ‘bits’
14. PK RNG studies
Disadvantages
Reductionist? (séance dice random numbers)
Lack of ecological validity
Unlike dice, process by which numbers are generated not
likely to be understood by participants – will they know
what to influence?
15. PK RNG studies
Radin and colleagues, 3 meta-analyses:
Effect size
statistic (π)
Radin & Nelson, 1989 (597 trials) .50018
Radin, 1997 (339 trials) [as above, but w/o PEAR studies] .50061*
Radin & Nelson, 2003 (515 trials) [inc. all 258 PEAR studies .50005
entered as one trial]
*Author had reported an effect size of .51, due to unweighted average
Limitations
Inclusion/exclusion criteria not explained
Includes some studies of animals
Inconsistent feedback methodologies
Included “pseudo-RNG” studies
PEAR studies anomalous
16. PK RNG studies
Bösch, Steinkamp, & Boller (2006), meta-analysis:
Effect size
statistic (π)
Overall sample (380 trials) .499997
Overall sample minus 3 largest trials (377 trials) .500048
“Monte Carlo” simulations (n > 1,000) demonstrated
extremely high probability of file-drawer effect
Conclusion: no PK effect
Recommendation: advance registration of PK trials