The Harvard trained physicist and famous philosopher and historian of science, Thomas Kuhn, often refers to a psychological experiment in his book ‘The Structure of Scientific Revolutions’ whereby individuals fail to notice individual anomalous cards within a deck.
The experiment illustrates the extent to which people can struggle when they are confronted with information that does not accord with what they have been taught.
Kuhn suggests the experiment demonstrates the nature of the mind and also the process of scientific discovery.
He has written:
‘In science, as in the playing card experiment, novelty emerges only with difficulty, manifested by resistance, against a background provided by expectation.’
In the experiment Jerome Bruner and Leo Postman asked people to identify individual cards from a deck of 52. Many of the cards are normal, but some are what Kuhn describes as anomalous. That is, for example, a six of spades may be coloured red while a four of hearts black.
Continuing to quote from Kuhn:
‘Each experimental run was constituted by the display of a single card to a single subject in a series of gradually increased exposures. After each exposure the subject was asked what he had seen, and the run was terminated by two successive correct identifications. Even on the shortest exposures many subjects identified most of the cards, and after a small increase all the subjects identified them all. For the normal cards these identifications were usually correct, but the anomalous cards were almost always identified, without apparent hesitation or puzzlement, as normal.
‘The black four of hearts might, for example, be identified as the four of either spades or hearts. Without any awareness of trouble, it was immediately fitted to one of the conceptual categories prepared by prior experience.
‘One would not even like to say that the subjects had seen something different from what they identified. With a further increase of exposure to the anomalous cards, subjects did begin to hesitate and to display awareness of anomaly. Exposed, for example, to the red six of spades, some would say: That’s the six of spades, but there’s something wrong with it—the black has a red border. Further increase of exposure resulted in still more hesitation and confusion until finally, and sometimes quite suddenly, most subjects would produce the correct identification without hesitation. Moreover, after doing this with two or three of the anomalous cards, they would have little further difficulty with the others. A few subjects, however, were never able to make the requisite adjustment of their categories. Even at forty times the average exposure required to recognize normal cards for what they were, more than 10 per cent of the anomalous cards were not correctly identified. And the subjects who then failed often experienced acute personal distress. One of them exclaimed: “I can’t make the suit out, whatever it is. It didn’t even look like a card that time. I don’t know what color it is now or whether it’s a spade or a heart. I’m not even sure now what a spade looks like. My God!”’
Everyone should read Kuhn’s book ‘The Structure of Scientific Revolutions’ published in 1962 and available from Amazons and on Kindle. The book provides a framework from which to ponder current attitudes to AGW and the lack of a unifying theory of climate. I think Kuhn would consider AGW pre-science and faddish.