The human paradox that is common sense
The human paradox that is common sense
By Duncan Watts, New Scientist, 7/13/2011
Even as common sense helps us make sense of human behaviour, it can undermine our ability to understand it

IN JANUARY 1998, about halfway through my first year out of graduate school, where I'd just completed a PhD in engineering, my housemate handed me a copy of New Scientist containing a book review by the physicist and science writer, John Gribbin. The book was Tricks of the Trade by Chicago sociologist, Howard Becker, mostly a collection of Becker's musings on how to do productive social science research.

Gribbin clearly hated it, judging Becker's insights to be the kind of self-evident checks that "real scientists learn in the cradle". But Gribbin didn't stop there, noting that the book had merely reinforced his opinion that all social science was "something of an oxymoron" and that "any physicist threatened by cuts in funding ought to consider a career in the social sciences, where it ought to be possible to solve the problems the social scientists are worked up about in a trice".

Twelve years later, and now a sociologist myself, I've learned that Gribbin is not alone in his scepticism about what social science offers. To many people, and I suspect to many readers of this magazine, it is deeply unclear what sociology has to say about the world that an intelligent person couldn't have figured out on their own. It's a reasonable question, and as a former "hard" scientist, it's one that I admit to having asked myself. But as Paul Lazarsfeld, one of the giants of 20th-century American sociology, pointed out nearly 60 years ago, it also reveals a common misconception about the nature of social science.

Lazarsfeld was writing about The American Soldier, a recently published study of over 600,000 servicemen, conducted by the research branch of the war department during and immediately after the second world war. To make his point, Lazarsfeld listed six findings that he claimed were representative of the report. Take number two: "Men from rural backgrounds were usually in better spirits during their Army life than soldiers from city backgrounds."

"Aha," says Lazarsfeld's imagined reader, "that makes perfect sense. Rural men in the 1940s were accustomed to harsher living standards and more physical labour than city men, so naturally they had an easier time adjusting. Why did we need such a vast and expensive study to tell me what I already knew?" Why indeed.

But Lazarsfeld then reveals the truth: all six of the "findings" were in fact the exact opposite of what the study found. It was city men, not rural men, who were happier during their army life. Of course, had the reader been told the real answers in the first place, they could just as easily have reconciled them with other things they already thought they knew: "City men are more used to working in crowded conditions and in corporations, with chains of command, strict standards of clothing, etiquette, and so on. That's obvious!" But this is exactly the point Lazarsfeld was making. When every answer and its opposite appears equally obvious then, as he put it, "something is wrong with the entire argument of 'obviousness'".

Lazarsfeld was talking about social science, but as I argue in my new book, his point is just as relevant to any activity that involves understanding, predicting, changing or responding to human behaviour, from marketing to politics to policy-making.

Politicians dealing with urban poverty feel they already have a good idea why people are poor. Marketers planning campaigns already feel that they have a decent sense of what consumers want and how to make them want more of it. Economic policy-makers believe that they can do a reasonable job of getting the incentives right, whatever end they are trying to achieve. They don't expect to get them right all the time, and they would be the first to admit that it's complicated. Nevertheless, they do think the problems they are contemplating are mostly within their grasp, that they are "not rocket science".

What's puzzling about this attitude is that if we compare recent progress in the physical versus the social sciences, it should be clear that we're actually much better at rocket science than managing the economy, merging corporations, or even predicting how many copies of a book will be sold.

So why does rocket science seem hard, while problems to do with people - which in some respects are clearly much harder - seem like they ought to be just a matter of common sense?

As it turns out, the key is common sense itself. Common sense is exquisitely adapted to handling the kind of complexity that arises in everyday situations, such as how to behave at work versus in front of your children versus in the pub with your mates. And because it works so well in these situations, we're inclined to trust it.

But situations involving corporations, cultures, markets, nations and global institutions exhibit a very different kind of complexity. Large-scale social problems necessarily involve anticipating or managing the behaviour of many individuals in diverse contexts over extended periods of time. Under these circumstances, the ability that Lazarsfeld highlighted of common sense to rationalise equally one behaviour and also its opposite causes us to commit all manner of prediction errors.

Yet because of the way we learn from experiences - even ones that are never repeated - the failings of common sense reasoning are rarely apparent to us. Rather, they manifest simply as "things we didn't know at the time" but which seem obvious in hindsight.

The paradox of common sense, then, is that even as it helps us make sense of the world, it can actively undermine our ability to understand it.

Duncan Watts directs the Human Social Dynamics group at Yahoo! Research. His book, Everything is Obvious (Once You Know the Answer): How common sense fails is published by Atlantic Books and Crown Business