Everything is Obvious (Once You Know the Answer), by Duncan Watts, had been on my wishlist for a while before my sister gave it to me for my birthday. I was already sympathetic to the book's key point: many conclusions of social science research that seem obvious in retrospect could not have been distinguished from other equally likely hypotheses a priori. In this post I briefly comment on one example from the book, its core argument, and its organization and style.

american-soldier-bookMy favorite example from the book comes from Paul Lazarsfeld's discussion of The American Soldier. That report studied over 600,000 troops during and just after WWII. Lazarsfeld listed six key findings, which I quote here directly:

  1. Better educated men showed more psycho-neurotic symptoms than those with less education. (The mental instability of the intellectual as compared to the more impassive psychology of the man-in-the-street has often been commented on.)
  2. Men from rural backgrounds were usually in better spirits during their Army life than soldiers from city backgrounds. (After all, they are more accustomed to hardships.)
  3. Southern soldiers were better able to stand the climate in the hot South Sea Islands than Northern soldiers (of course, Southerners are more accustomed to hot weather).
  4. White privates were more eager to become non-coms than Negroes. (The lack of ambition among Negroes is almost proverbial.)
  5. Southern Negroes preferred Southern to Northern white officers. (Isn't it well known that Southern whites have a more fatherly attitude toward their "darkies"?)
  6. As long as the fighting continued, men were more eager to be returned to teh States and they were after the German surrender. (You cannot blame people for not wanting to be killed.)

Spend a minute thinking about these results. Although some are undoubtedly political incorrect, others seem intuitive don't they? As Watts says, a reader could easily imagine that, "Rural men in the 1940s were accustomed to harsher living standards and more physical labor 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 could have figured out on my own?" (p. xvi)

Lazarsfeld was playing a trick, though. In fact, the studies conclusions were just the opposite--and with the benefit of hindsight those could seem just as obvious. What seems like common sense after the fact was just one of several possibilities before the research was conducted.

According to Watts, common sense biases like these come in three forms. The first error is imagining others' motives to be like our own if we were put in their situation--what I call armchair theorizing. The second error is failing to recognize that "more is different." Models that portray the actions of groups as a simple linear aggregation of individuals are often dead wrong at predicting that outcomes of social processes. More often, social dynamics are nonlinear (see, for example, research in "information cascades"). Thirdly, we often suffer from hindsight bias, failing to recognize that historical outcomes we now take for granted were highly contingent and not easily predictable beforehand.

The book is divided into two parts: "Common Sense" and "Uncommon Sense". The first part focuses on examples of the three common sense biases at work, and the second provides recommendations for social science research. Both parts refer heavily to the author's previous work and other "big think" books--a genre that I hadn't realized this book belonged to before reading.

Overall, Everything is Obvious is a quick read that will bring a social science outsider up to speed in cognitive biases and suggest some resources for learning more. For the practicing social scientist already familiar with the work of Daniel Kahneman and others like him, I would recommend skipping the first half in favor of the chapter summaries in the appendix, and reading the second half with a pen in hand to mark areas that you want to follow up on in the original literature. You can also read Andrew Gelman's review here.