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Rhine tested telekinesis by dice throws and telepathy, and clairvoyance by ‘Zener cards’, so
named because they had been invented by his Duke colleague Dr Karl Zener. Each Zener card
was marked with a symbol: a circle, a rectangle, a star, a cross, or an image of waves. Each
pack of twenty-five cards had five bearing each of the five symbols. To test for clairvoyance,
Rhine would ask his subject to shuffle the cards, cut them, and then identify the symbol on the
topmost card without looking at it. To test for telepathy he would think of a particular symbol,
then ask the subject to read his thoughts. As he reported rather triumphantly in his first book,
Extra-Sensory Perception, in these experiments he obtained results far better than chance alone
could account for.^9
Soal’s innovations
Almost immediately upon its publication, Rhine’s work provoked a barrage of criticism from
within and without the psychic research community. The naysayers questioned everything
from his statistical methodology, to the arrangement of the rooms in which he conducted his
trials, to the thickness and cut of the Zener cards. His failure to use controls was faulted, as
were the thoroughness of his shuffling and the reliability of the dice employed in the telekinesis
testing. Dozens of ways in which his subjects might have cheated were proposed. For his part,
Rhine averred that his priority was to
interest the subjects in the test, and create confidence in the possibility of doing well . . . My rela-
tions with my subjects were friendly, almost fraternal. We did hypnotic demonstrations, spent
long hours in discussion, and pretty completely dissipated the constraints that usually exist for
the student in the laboratory and in the presence of his instructor.
In addition to hypnosis, he tested some of his subjects under the influence of sodium amytal
and caffeine.^10
The trouble was that no other American researchers could reproduce Rhine’s results. Nor
could S. G. Soal, who in 1934 attempted a repetition of Rhine’s experiment employing several
safeguards that Rhine had not. Of these, the most notable was his decision to replace the usual
packs of twenty-five Zener cards by cards in which the five symbols were not equally distrib-
uted. Instead, ‘by the use of mathematical tables’ Soal compiled a random sequence of 1000 card
symbols, which he split into forty packs of twenty-five cards each. Among other things, this
innovation allowed him to correct for the possibility that the guessers might be making sure
not to call any one symbol more than five times. Unfortunately, in tests for both clairvoyance
and telepathy, the results he obtained were disappointing, with only one subject, Mrs Gloria
Stewart, obtaining a score high enough to be ‘of any possible interest’.^11
At this point Soal might well have given up, had not W. Whately Carington, a colleague
from the SPR, insisted ‘with remarkable pertinacity’ that he re-examine his data and compare
‘each guess, not with the card for which it was originally intended, but with the immediately
preceding card and the immediately following card, and count up the hits’. As Gloria Stewart
was ‘the only “telepathy” subject who had shown any promise at all’, Soal chose her results for
reappraisal, calculating both her ‘post-cognitive’ and ‘precognitive’ hits. This was in 1939. What
he discovered, he later wrote, was so ‘remarkable’ as to impel him to undertake a second round
of experiments.^12