An Hypnotic Numbers Game

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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