When we’re very busy it is
easy to forget things. Often things that we should have done, but at the same
time our focus keeps those things that we’ve just done clearly in mind. Usually
that vivid short-term memory is a good thing as it prevents us from doing
things over that we’ve already done. However, those academic psychologists will
always find a task that upsets our suppositions.
Terhune and Brugger are the
latest to do this by asking a group of subjects to generate a series of random
numbers using the numerals of 1 through 6 (1). The problem is that as we
concentrate on the task in hand, we remember the last few numbers and try and
avoid them. Thus our short-term memory distorts the randomness.
In an effort to find good
human random number generators (RNGs), Terhune and Brugger used hypnosis to
make people forget. They sifted through a group of 600 willing candidates to
pick 20 lucky potential RNGs. 8 of these had a low susceptibility to hypnotic
suggestion, whilst 12 were highly susceptible.
The aim was to make the
subjects have short-term amnesia so they would forget what they had just said,
numberwise, that is. Of the 12 highly suggestibles, 4 could also be classified
as highly dissociative. In psycho-speak, that means that they were liable to
short-term amnesia. The remaining 8 were classified as low dissociative
candidates who were going to be more tenacious.
The experiment ran in three
sections. A baseline was established; the subjects hypnotized and told to forget
the number that they had just said; then they were snapped out of their trance
and went back to normal.
Results are, of course,
what we want to get to. Only the highly dissociative, highly suggestible group
repeated numbers just used as would be found in a computerized RNG. The other
groups avoided numbers just used and so weren’t very good RNGs.
This leaves 4 out of 600
people who, with hypnosis, might make a reasonable stab at being an RNG. On the
whole, I think it will be easier to stick to using my computer next time I need
a table of random numbers.
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