Invisible Influence: The Hidden Forces that Shape Behavior - Softcover

Über die Autorin bzw. den Autor

Jonah Berger is a marketing professor at the Wharton School at the University of Pennsylvania and internationally bestselling author of Contagious, Invisible Influence, and The Catalyst. He’s a world-renowned expert on social influence, word of mouth, and why products, ideas, and behaviors catch on and has published over 50 papers in top-tier academic journals. He has consulted for a range of Fortune 500 companies, keynoted hundreds of events, and popular accounts of his work often appear in places like The New York Times, The Wall Street Journal, and Harvard Business Review. His research has also been featured in the New York Times Magazine’s “Year in Ideas.”

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Invisible Influence

1. Monkey See, Monkey Do

What could be easier than matching the length of two lines?

Imagine you were asked to participate in a basic vision test. In front of you is a pair of cards. On the left card is a line. And on the right card are three comparison lines, A, B, and C.

Your job is simple. Just pick the line on the right that is the same length as the target line on the left card. Decide whether line A, line B, or line C is the same length as the target line. Should be easy, right?



Now let’s add one more wrinkle. Rather than doing the experiment alone, you participate with a group of your peers.

You show up at a nondescript building on a university campus, and walk up a flight of stairs to room B7. You see that six other people are already seated around three sides of a square table, so you grab the last remaining chair, the second from the end.

The experimenter gives the instructions. He reiterates that your job is to pick the line on the right that is most similar in length to the one on the left. The group will do a number of trials just like the one above. As the group is small, and the number of trials relatively few, he’ll call on each person in turn to announce their choice, which he’ll record on a special form.

The experimenter points to the person on the left side of the table and asks him to start. This first participant has red hair, is wearing a grey collared shirt, and seems to be around twenty-five years old. He looks at the same lines you saw on the last page and, without missing a beat, reports his judgment: “Line B,” he says. The next participant seems a little older, maybe around twenty-seven, and is dressed more casually. But he reports the same answer. “B,” he says. The third person also says B, as does the fourth, and the fifth, and then it gets to you.

“What’s your answer?” asks the experimenter. Which line would you pick?

When psychologist Solomon Asch designed this line length study in 1951, he was testing more than people’s vision. He was hoping to prove someone wrong.

A few years earlier another psychologist, Muzafer Sherif, had conducted a similar study and found surprising results.1 Sherif was interested in how norms form—how groups of people come to agree on common ways of seeing the world.

To study this question, he put people in an unusual situation. In a dark room, Sherif displayed a small pinpoint of light on the wall. He asked people to stare at the light and not move their eyes for as long as possible. Then he asked them to report how far the point of light moved.

The point of light was immobile. It didn’t move at all.

But for individuals in the room, the light seemed to shift ever so slightly. Gazing at a small dot of light in an otherwise dark room is tougher than it sounds. After staring in the darkness for a while, our eyes fatigue and move involuntarily. This tendency causes the point of light to seem as though it moves even though it doesn’t.

Sherif studied this phenomenon, called the autokinetic effect, because he wanted to see how people might rely on others when they were uncertain.

First he put people in the room alone, by themselves. Each person picked a number based on how far they thought the light moved. Some people thought two inches, others thought six inches. Different people’s estimates varied widely.

Then, Sherif put those same people into groups.

Rather than making their guesses alone, two or three participants would be in the room at the same time, each making estimates that the others could hear.

People didn’t have to agree; they could guess whatever they wanted. But when placed together, what was once a discordant mix of differing views soon became a symphony of similarity. In the presence of their peers, the guesses converged. One participant might have said two inches when she was by herself, while another might have said six inches. But when placed together they soon came to a common estimate. The person who said two inches increased her estimate (to something like three and a half inches) and the person who said six inches decreased his estimate (to something like four inches).

People’s estimates conformed to those around them.

This conformity happened even though people were unaware it occurred. When Sherif asked participants whether they were influenced by the judgments of others, most people said no.

And social influence was so strong that it persisted even when people went back to making judgments by themselves. After the group trials, Sherif split people up and had them return to making guesses alone. But people continued to give the answers that they had settled on with the group, even after the group was gone. People who had increased their estimates when others were in the room (from two to four inches, for instance) tended to keep guessing that larger number even when they were by themselves.

The group’s influence stuck.

Sherif’s findings were controversial. Do people just do whatever others are doing? Are we mindless automatons who simply follow others’ every action? Notions of independence and free thought seemed at stake.

But Solomon Asch wasn’t convinced.

Asch thought conformity was simply a result of the situation Sherif used. Guessing how far a point of light moved wasn’t like asking people whether they like Coke or Pepsi or whether they want butter or cream cheese on their bagel. It was a judgment most people had never made, or even thought of making. Further, the right answer was far from obvious. It wasn’t an easy question. It was a hard one.

In sum, the situation was ripe with uncertainty. And when people feel uncertain, relying on others makes sense. Others’ opinions provide information. And particularly when people feel unsure, why not take that information into account? When we don’t know what to do, listening to others’ opinions, and shifting ours based on them, is a reasonable thing to do.

To test whether people conformed because the answer was uncertain, Asch devised a different experiment. Rather than putting people in a situation where the answer was unclear, he wanted to see what they would do when the answer was obvious. When people could easily tell the correct answer right away and thus would have no need to rely on others.

The line-length task was a perfect choice. Even those with poor eyesight could tell the correct answer. They might have to squint a little, but it was right there in front of them. There was no need to rely on anyone else.

Asch thought that when the answer was clear, conformity would be reduced. Drastically. To provide an even stronger test, Asch rigged the group’s responses.

There was always one real participant, but Asch filled the rest of the room with actors. Each actor gave predetermined responses. Sometimes they gave the right answer, picking the line on the right that was the same as the one on the left. But on other preselected trials, all of them gave the same wrong answer, saying “Line B,” for example, when the answer was clearly line C.

Asch used the line task because he assumed it would reduce conformity. Real participants could see the right answer, so it shouldn’t matter that others gave the wrong response. People should act independently and go with what they saw. Maybe a...