Why are the predictions of well known experts worse than those of people who linger in obscurity? Isaiah Berlin’s distinction between the hedgehog, who knows one big thing, and the fox, who knows many little things, provides a clue to the answer.
Isaiah Berlin, historian of ideas, made a distinction between the intelligence of the hedgehog – which knows one big thing – and the intelligence of the fox – which knows many little things. Hedgehogs fit what they learn into a world view. Foxes improvise explanations case by case. The world needs both but today it needs fewer hedgehogs and more foxes. Berlin’s terms are used to describe styles of reasoning by the American psychologist Philip Tetlock, who has spent 20 years asking pundits to predict who will win elections, what countries will acquire nuclear weapons or enter the European Union and how the first Gulf war would end. He has tested 30,000 predictions from 300 experts against outcomes.
Mr Tetlock finds that his respondents are not very good. They do better than a chimp who answers at random, but not much, and worse than simple forecasting rules based on extrapolation. But some pundits are better than others. A little knowledge is helpful. Dilettantes – people with the information you will acquire from diligent reading of this newspaper – do much better than undergraduates who based their judgment on a one-page summary of the issues. But experts have little advantage over dilettantes. The reputation of the experts is a guide to which are worth following. But not in the way you might expect. Bad forecasters are consulted more frequently than good ones. The more famous the expert, the worse his prognostications.
Mr Tetlock explains this intriguing result through the distinction between hedgehogs and foxes. He uses psychological tests to categorise his respondents. People who agree that “it is annoying to listen to someone who cannot seem to make up his or her mind” and “the most common error in decision-making is to abandon good ideas too quickly” are hedgehogs. People who say “when considering most conflicts, I can usually see how both sides could be right” and
“I prefer interacting with people whose opinions are very different from my own” are foxes.
Mr Tetlock’s analysis is about political judgment but equally relevant to economic and commercial assessments. Foxes are better at prediction than hedgehogs because they derive information from many sources, adjust their views in line with events and see a range of perspectives on each situation. Hedgehogs have one clear view, seek evidence that confirms that view and have ready explanations for apparent failures of foresight.
But these hedgehog characteristics are exactly those that politicians, journalists and business leaders demand of advisers and commentators. Harry Truman famously sought a one-armed economist, who would never say: “On the one hand, then on the other.” Broadcast media look for snappy soundbites. Corporate executives demand “the elevator pitch” for new ideas. Fund managers want specific forecasts. Business audiences do not want to hear that the world is a complex and uncertain place. But, unfortunately, it is.
Leaders need many hedgehog qualities – the cry that the probability of victory is 0.6 is not inspiring. But the analytic skills needed for good judgments are those of foxes. Effective management teams include both hedgehogs and foxes, which is why the modern tendency to appoint hedgehogs and allow them to surround themselves by like-minded hedgehogs is so dangerous. It is not difficult to see how George W. Bush would score on Mr Tetlock’s personality tests. Political hedgehogs invade Iraq, business hedgehogs go to China and financial hedgehogs hype the new economy. While a few political geniuses may successfully display the skills of both hedgehog and fox, these attributes are normally incompatible. The cult of the heroic CEO, which invites us to believe all characteristics required for great leadership and good judgment can be found in a few exceptional individuals, flies in the face of psychological research as well as long experience.
Philip Tetlock’s new book Expert Political Judgment is published by Princeton University Press; John Kay’s new book The Hare & the Tortoise by the Erasmus Press