Mind Over Matter?

Sue Blackmore - 1 August 1991

People are very bad at estimating probability or understanding chance and randomness. Such innumeracy could well explain much of the phenomena currently treated as paranormal. This article, adapted from ones appearing in New Scientist and the Auckland Star deals with the illusions of probability that lead to claims of psychic powers.

More than half the population believes in psychic phenomena, and most claim to have experienced telepathy, precognition or psychokinesis. But experiments in parapsychology over 50 years have failed to convince most scientists that paranormal powers really exist.

Now a growing body of new psychological research suggests that the experience may not be due to astral vibrations or the power of the spirits, but to the way our minds look for non-existent connections. It is rather like a visual illusion, but an illusion of probability rather than of vision.

If the paranormal does not immediately seem like a case of probability, think of an example. You wake up one morning from a dream in which your friend Ferdinand lies dead on the grass by a foreign motorway, covered in a white sheet. The very next day you hear that Ferdinand died that night.

Anyone who has this experience is likely to say: “It couldn’t possibly be a coincidence. It must be psychic.” That is where the mistake occurs.

It could be a coincidence, and probably was. Statistician Christopher Scott has calculated that, assuming only one death dream per person per lifetime, and allowing for the number of people in Britain and the number who die each day, a coincidence like this ought to happen to someone, somewhere in Britain, once every two weeks.

Of course, if you were one of them, you would have to be superhuman not to be affected by it.

It would seem even more stunning if Ferdinand died in a car crash, or was in hospital covered in a white sheet. Ina typical dream there may be hundreds of identifiably separate details which could be right, yet we forget most of them and only remember the ones which are confirmed, so exaggerating the coincidence.

Even meeting friends in odd places is susceptible to a simple analysis. One researcher calculated that his social network included 212 people whom he would greet if he met them.

On a typical trip away from home he counted seeing 460 people. On this basis he ought to expect to meet a friend in an unusual place rather often.

Probability Test

The basic fact is that humans are not good at understanding probability. If you think you are an exception, try the questions in the box.

Do not be dismayed if you get some wrong. Psychologists have found that people tend to make probability estimates based on rather rough heuristics, rather than anything like a mathematical calculation. For example, they might see how many instances of something they can “bring to mind” and base their guess on that. Not very accurate — but it may be the best we can do.

Part of the problem may be that we have evolved ways of thinking appropriate to a much simpler life than the world of television pictures and instant communications we have today.

If this theory of psychic experiences is correct, it should be testable. One prediction is that people who believe in the paranormal (termed “sheep”) should be less accurate in probability judgments than disbelievers (goats). This was confirmed in a series of experiments at Bristol University.

In particular, the sheep did worse at tasks requiring them to understand randomness. Perhaps this is why perfectly random coincidences in their everyday life appear to be strange, leading them to look for paranormal explanations. Interestingly, university students did no better than schoolchildren, which implies that these judgments are not improved by education.

The other major kind of psychic experience is PK, or psychokinesis — the claimed effect of mind over matter. It now seems that this too might be an illusion.

Illusion Of Control

As babies, and throughout our lives, we learn how to control our environment by observing the coincidences between our own actions and the effects that follow. Here again, because we don’t understand probability, we can easily think we have controlled something random. This is known as the “illusion of control”. It can affect everything from feeling you can control the weather to believing your willpower affects the fall of dice.

This feeling of being in control can easily overwhelm logic. The most bizarre example I ever experienced was taking part in a ritual to make the sun rise at dawn on Midsummer Day. After hours of chanting and processing, when the sun popped up dead on schedule, we really felt as though we had made it happen!

If this is the right interpretation, then, again, we would expect sheep to be more prone to an illusion of control than goats, and this is exactly what is found. In experiments at Bristol University, subjects tried to control a flipping coin on a computer screen. Not only did the sheep think they had more control, even when the coin was random, but they dramatically underestimated the chance rate of success. This would mean that even in a chance world they would still be looking for explanations and concluding “it must be psychic”.

This may not be the whole story, and the paranormal may yet exist, but we do not need to invoke it to account for the experiences — they certainly happen and affect people deeply, but it may be all illusion.

Dr Susan Blackmore is in the department of psychology at the University of Bristol and the University of Bath.