The oil slick effect, or why we systematically overgeneralize

If you have colleagues, what do you think of them? Are they smart? Competent? Motivated? Open to new ideas? Good communicators? Do they work well as a team? The answer may not depend on what you think. And this fact points to the reason why the modern world now seems so venomously polarized.

In the 1970s, psychologist Barry Staw gave a collaborative task to groups of strangers, inviting them to analyze some corporate data and make a prediction about the company’s future earnings and sales. When the task was completed, he told each participant how well their group’s predictions had performed. He then asked these people to rate the group they were working with.

But Stav was lying for the good: he randomly gave each group’s forecast good or bad marks. There was no connection between how well the band performed and how well Staw said they performed. However, Stav found that when people believed their group had made an accurate prediction, they told him they were working with open, driven, clear, intelligent, and collaborative people.

But when they were falsely told that their group had made poor predictions, they explained to Stav that this was not surprising since the group was narrow-minded, lazy, abstruse, stupid, and mutually hostile.

Subsequent researchers found the same pattern even when they repeated the experiment with well-performing teams. As Phil Rosenzweig explains in his book halo effect, this behavior is not limited to colleagues. We have a systematic tendency to overgeneralize both praise and blame. Profitable companies are expected to have superior policies and procedures across the board. This halo effect works in reverse as well: scandal-ridden politicians see their opinion poll ratings drop on everything from economic competence to foreign policy. Obviously, we struggle to accept that something can be good in some ways and bad in others, whether it be the president, a corporation, or our own teammates.

The reverse halo effect is sometimes referred to as the “devil effect” or “horn effect”. None of the terms stuck. So let me suggest something else: the oil slick effect. Disagreements, like oil slicks, spread much farther and more perniciously than we think. It is not possible for someone to simply be wrong about something; they must be wrong about everything, and wicked, too. An oil slick covers everything and ruins everything.

I can’t help but wonder if this oil slick effect is worse than before. Consider the following data from Ezra Klein’s book. Why are we polarized: In 1960, when Americans who supported Republicans or Democrats were asked if they would object to their son or daughter marrying outside the party political line, very few protested: 5 percent of Republicans and 4 percent of Democrats.

When the same question was asked 50 years later, opposition to interparty marriage had risen nearly tenfold, to 49% of Republicans and 33% of Democrats. Politics has gone from something that reasonable people could agree to ignore to an all-consuming Shark-Jets-style vendetta in which crossing a political barrier is an unforgivable betrayal. The oil slick has shifted from political to personal.

This might be understandable if the stakes in politics were raised, but the facts are that politics itself hardly matters. Republicans in the US used to be free traders; in Britain the Conservatives used to be pro-business. Most of their constituents don’t seem to mind significant changes in their political platforms – their loyalty is tied to something else.

The halo effect is not new. It was first named and identified by psychologist Edward Thorndike over a century ago. Why could she become more acute? One clue comes from a study done a decade ago by three social psychologists: Angela Bunce, Kate Pickett, and Christian Crandall. They studied friendship groups on small and large college campuses. At first glance, large campuses seemed more diverse, but with a wider choice of possible friends, students clustered into groups of like-minded people. On smaller campuses, with fewer choices, they were forced to forge friendships over potentially uncomfortable differences in attitudes towards politics, religion, sex, and lifestyles such as exercise and smoking.

Perhaps the modern world is increasingly like a large campus – full of a huge variety of views, but at the same time offering us every opportunity to connect with people like us. This is most evident on social media, where by design we self-isolate, but we can also choose our own podcasts and politically sympathetic TV channels.

As Bill Bishop stated in his book Big Grade, we are even grouped into socially homogeneous areas. The world has become wider and more diverse, which means that we have a narrower choice of who we deign to read, watch or even drink with. The halo effect has long been a feature of our psychology, and there has always been a temptation to let an oil slick poison our thinking. This poisonous temptation left a person isolated and no one could meet their standards of cleanliness. Today, the oil slick is free to spread.

Written and first published in Financial Times May 13, 2022

Soft cover data detective was published on February 1 in the US and Canada. Name elsewhere: How to fold the world.

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