cooper@pbsvax.DEC (Topher Cooper DTN-225-5819) (02/13/86)
<< The following was posted last week but only seems to have reached
net.origins, therefore I am reposting. Sorry if this reaches you twice.>>
Matthew P Wiener (ucbvax!brahms!weemba) writes:
>In article <631@oakhill.UUCP> davet@oakhill.UUCP (Dave Trissel) writes:
>>"A recent experiment indicates that inexperienced subjects can bring about
>>genetic mutations in bacteria - a finding which has profound implications
>>for the health industry and for evolutionary theory.
>> .... .... ....
>> How? By merely 'wishing'.
>> .... .... ...."
>
>I am curious, though, how the results (clear vs red) were recorded.
>The 'wishing' worries me. A fun game I used to play with friends
>was to convince them that Venus was an airplane, and that if they
>stared hard and long enough, they would see it move. About half of
>them could be convinced it was moving.
It shouldn't worry you. The danger of non-blind judging is well understood
in parapsychology.
The following information was taken from the report of the experiment which
appeared in the April (not October as reported in Dave's summary) 1984 issue
of the Journal of the American Society for Psychical Research
(Nash, Carroll B., "Test of Psychokinetic Control of Bacterial Mutation",
JASPR, Vol 78, #2, p 145-152). This report is substantially the same as one
delivered by Dr. Nash at the annual convention of the Parapsychology
Association in 1983.
The subjects were the ones who did the wishing. Each subject was given a
different, randomly selected card saying which three of his or her nine
tubes of E. Coli should be "mutation-promoted" which should be "mutation-
inhibited" and which three should be control tubes. The subjects were
supervised by three premed students (each had their own group of 20 subjects,
8 subjects were dropped from the study before measurements were made because
of procedural errors). The assignment of tubes to conditions was unknown
to the experimenter, the records used later for assessment of results were
kept sealed.
The "color" of the strains only shows up when they are cultured in a special
medium containing a pH indicator. The tubes were incubated for 24 hours,
diluted and multiple cultures placed on the special culture medium. The
culture plates were then incubated for a further 24 hours. Apparently at
this point each culture on a plate appears either distinctly red or distinctly
clear. Presumably any ambiguous cultures would be dropped from the total.
The index for the tube is the proportion of the cultures taken from it which
were distinctly red.
This was evaluated before the sealed envelopes indicating which tubes for each
subject were in which condition.
This experiment is interesting because it appears to show a previously
undocumented effect: PK controlled mutation. It is only suggestive, however,
because of various weaknesses in the procedure and the interpretation. By
the standards of parapsychology, this is a fairly sloppy experiment (from
what I know of medical, biological and psychological experimental standards,
however, it would be considered reasonably clean from the viewpoints of those
fields). The weaknesses are discussed in the report.
1) I would not consider the experimenters as a priori reliable as more
mature experimenters. Dr. Nash's seems to personally feel that they
were reliable.
2) Two of the experimenters did not supervise the subjects at all times
when they were in the presence of the tubes of bacteria. It is not
clear what manipulation they could have done to accomplish the effect
found. A single "cheater" would have not made a significant
difference to the results.
3) The subjects had contact with the scorers (the experimenters) after they
had been given their target assignments. It seems unlikely, though
it's conceivable, that enough subjects had unconsciously passed enough
biasing information to all three scorers to produce the results found.
4) The procedure does not differentiate the subjects using PK to influence
the rate of mutation in the bacteria, from the subjects using PK to
cause differential survival of the two strains. I think that this is
the most serious defect of the experiment.
Topher Cooper
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Disclaimer: This contains my own opinions, and I am solely responsible for
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