Hindsight bias distorts our view of the world. Everything is obvious and expected in retrospect, but no one has the ability to foresee such results. This cognitive bias limits our appreciation for real science.

Meyers’s Exploring Social Psychology challenges this bias and shows us how confusing reality may be. (via Overcoming Bias)

Social science, for the most part, identifies patterns and probable behavior but has little power to explain causes of these patterns. This means that social science, psychology, and evolutionary biology are historical sciences rather than predictive ones. Yet due to hindsight bias, historical results are deemed “obvious” as if people knew what would occur beforehand. Social science is nothing more than common sense.

Except it is not. Individuals update their common sense to describe past information rather than predict future events. Our rational models we use to explain the world around us are far less complete and less comforting than we would like to believe.

The I-knew-it-all-along phenomenon not only can make social science findings seem like common sense but also can have unhealthy consequences. It is conducive to arrogance — an overestimation of our own intellectual powers.

One problem with common sense, however, is that we invoke it after we know the facts.

David Meyers gives an example:

Is the first objection valid: does social psychology simply formalize what any good amateur social psychologist already knows intuitively?

Cullen Murphy (1990), editor of The Atlantic, thinks so. So far as he can detect, the social sciences turn up “no ideas or conclusions that can’t be found in [any] encyclopedia of quotations. . . . Day after day social scientists go out into the world. Day after day they discover that people’s behavior is pretty much what you’d expect.” Nearly a half century earlier, historian Arthur Schlesinger, Jr., (1949) reacted similarly to social scientists’ studies of American World War II soldiers as reported in the two volumes of The American Soldier — “ponderous demonstrations” of common sense knowledge, he said.

What were the findings? Another reviewer, Paul Lazarsfeld (1949), offered a sample with interpretive comments, a few of which I paraphrase:

  1. Better educated soldiers suffered more adjustment problems than less educated soldiers. (Intellectuals were less prepared for battle stresses than street-smart people.)
  2. Southern soldiers coped better with the hot South Sea Island climate than Northern soldiers. (Southerners are more accustomed to hot weather.)
  3. White privates were more eager to be promoted to noncommissioned officers than Black privates. (Years of oppression take a toll on achievement motivation.)
  4. Southern Blacks preferred Southern to Northern White officers (because Southern officers were more experienced and skilled in interacting with Blacks).
  5. As long as the fighting continued, soldiers were more eager to return home than after the war ended. (During the fighting, soldiers knew they were in mortal danger.)

Meyers notes that each of these has a common sense explanation. After reading any finding in psychology or social science, people claim they expected these results and will agree with common sense explanations or proverbial sayings.

And here’s the gotcha moment. The five above examples are the opposite of the real findings.

You perhaps experienced this phenomenon when reading Lazarsfeld’s summary of findings from The American Soldier. For actually, Lazarsfeld went on to say, “every one of these statements is the direct opposite of what was actually found.” In reality, the book reported that poorly educated soldiers adapted more poorly. Southerners were not more likely than Northerners to adjust to a tropical climate. Blacks were more eager than Whites for promotion, and so forth. “If we had mentioned the actual results of the investigation first [as Schlesinger experienced], the reader would have labelled these ‘obvious’ also. Obviously something is wrong with the entire argument of obviousness. . . . Since every kind of human reaction is conceivable, it is of great importance to know which reactions actually occur most frequently and under what conditions.

What we say is obvious was completely unexpected. Our ability to instinctively measure and describe probability and frequency of events is actually quite awful.

Our hindsight bias is non-falsifiable. We can explain anything as unsurprising. We use it for personal relationships, jobs, elections, and all types of events. Maybe it’s an empty comfort to get us through life.

If this hindsight bias (also called the I-knew-it-all-along phenomenon) is pervasive, you may now be feeling that you already knew about it.