IRRATIONALITY

The Enemy Within

Stuart Sutherland

Penguin, 1994.


Sutherland provides a stunning survey of psychological research on irrationality, arguing that irrational behaviour is far more widespread and normal than is generally supposed.

Rationality is defined thus:

"Rational thinking leads to the conclusion that is most likely to be correct, given the knowledge one has... a rational action is the one that, given the person's knowledge, is most likely to achieve his end."

Time and again people exhibit what is known as the availability error: judging by the first things that come to mind. What makes something available in this sense may be that it was recently experienced, or causes strong emotion, or leads to strong images being formed. (See also Habit.)

This type of error is common in people's estimates of risk. A study showed that people think they are twice as likely to die of an accident as from a stroke, whereas 40 times as many people die from strokes as from accidents. Because air crashes and other violent deaths are more dramatic and more widely reported, they loom larger in the mind and distort the judgement.

Sutherland discusses obedience to authority, conformity, group behaviour, misplaced consistency, rewards and punishments, drive and emotion, and the handling of evidence. He notes that people tend to seek confirmation of their hypotheses, whereas they should be trying to disconfirm them. Here he is expressing Karl Popper's view of the logic of science: "although it is impossible ever to prove a rule with certainty, a single discrepant observation refutes it".

There are so many fascinating and startling experiments referred to in this book that it is only possible to hint at the range of issues explored: "at a rough count, about a hundred different systematic causes for irrational thinking have been described".

Sutherland concludes from the research covered in the chapter on "The Failure of Intuition" that "intuition is in fact remarkably bad", in itself perhaps a counter-intuitive finding.

In the chapter on "Making the Wrong Connections", there are interesting cases of professional irrationality, including in Sutherland's own field. He condemns Rorschach tests:

"as a diagnostic tool the Rorschach along with other projective tests is virtually worthless and yet it has been very extensively used and indeed still is (one estimate is that six million Rorschach tests are given a year) - a glaring example of irrationality among psychologists".

In the supposedly pragmatic and tough-minded world of business, we find this curious situation:

"It has recently been found that 85% of the largest companies in Europe... employ graphologists in personnel selection. In the USA 3000 companies, including most banks, employ graphologists. What could be more natural than to believe that a person's hand-writing reflects his character? The belief may be natural, but it is wrong. A recent review of studies on graphology concluded that the validity of graphologists' assessments of personality was 'virtually zero'".

Could these companies be persuaded to spend their money on live music instead?



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Paul Taylor 2001