"I Knew It All Along!" *

David A. Gershaw, Ph.D.

Some people don't seem to think psychology courses are necessary, because they think that psychology is merely "common sense." This view is influenced by the hindsight bias the tendency to see outcomes as being obvious, but only after the fact.

The hindsight bias is a reason why proverbs seem to contain so much common wisdom. However, proverbs may directly contradict one another. For example, does "haste make waste"? Or is "he who hesitates lost"? If you are trying to make a decision of how to act in the future, it is extremely difficult to decide which one of these proverbs applies in your situation. In contrast, it is easy to see which proverb applies with hindsight.

The same effect holds true with the results of experiments. Suppose a social psychologist reports that separation increases the attraction between romantic partners. We are likely to reply, "Of course, absence makes the heart grow fonder," as if these findings were merely common sense. However, what if that same study would conclude that separation decreases the attraction between romantic partners? We would be just as likely to confidently remark, "Out of sight, out of mind."

In everyday life, we rarely expect something to happen, until it actually does. Once it happens, we seem to clearly see the factors that brought the event about thus we are not surprised at what happened.

A good example relates to Reagan's victory over Carter in the 1980 Presidential election. Commentators essentially said that Reagan's landslide victory was not surprising and was easily understandable. However, until the last few days of the campaign, most of these commentators were saying that the election was "too close to call."

One psychologist, Mark Leary, investigated this effect more scientifically. The day before the election, voters were asked how they thought the election would go. The average person predicted a slim Reagan victory. Another group of voters was interviewed the day after the election. They were asked what result they would have predicted the day before the election. Not surprisingly, most gave answers that corresponded much more closely to the actual outcome. Another psychologist, Jack Powell, found that essentially the same thing occurred in the 1984 Reagan-Mondale Presidential battle. With your hindsight, some of you may laugh at my use of the word, "battle," but how many of you would have laughed before the election?

The hindsight bias also tends to cause problems among students even psychology students in college. Once they read about the results of experiments, these results seem so predictable as if everything psychology discovers is merely common sense. With the results seeming so clear, this presents a problem to many students when they take tests. Faced with several possible outcomes on a multiple-choice test, the choice seems far from clear. Even though students think that they "know the material," it is much harder to predict the outcomes before the fact. Although some students may figuratively "kick themselves" for not seeing what seems obviously clear afterwards, others tend to blame it on the "tricky questions" in the test. (If you are a student at any level, beware of this phenomenon. Don't fool yourself into thinking that you know the material better than you actually do.)

Even more important, the hindsight bias can lead to an arrogant overestimation of our own cognitive abilities. For example, after the creation and acceptance of the typewriter, with their hindsight, people tend to see its invention and success as inevitable. However, in an 1872 letter, Christopher Latham, the inventor of the Remington typewriter, was far from sure. He stated, "My apprehension is (that) it will have its brief day and be thrown aside."

What was uncertain before the fact
becomes clear with the aid of hindsight.

Hindsight makes outcomes seem as if they could have been easily foreseen. If the decisions were wrong, the decision makers are likely to be blamed for their "obvious" ignorance. If they are right, they seem to have the wisdom of a sage. Thus some historians with their hindsight wonder how the United States government could not have noticed the "inevitability" of the Japanese attack of Pearl Harbor in 1941. Even Arthur Schlesinger, a member of the Kennedy administration, regrets "having kept so silent" in the discussions of the invasion of Cuba's Bay of Pigs that was such a failure.

Common sense is not always wrong, but it is conventional wisdom that often applies only under certain conditions. Being given after the fact, common sense is more capable of describing what has happened, rather than predicting what will happen in the future. Of course, after reading this article, some of you will still say, "I knew it all along."

* Adapted from David Myers' Social Psychology, McGraw-Hill, 1990, pages 18-20.

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