Invisible Influence: The Hidden Forces that Shape Behavior

ISBN-13: 9781476759739

Media Type: Paperback

Publisher: Simon & Schuster

Publication Date: 06-20-2017

Pages: 272

Product Dimensions: 5.50(w) x 8.38(h) x 0.80(d)

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.”

Read an Excerpt

Invisible Influence
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 couple participants would waver once in a while, but for the most part people should give the right answer.

They didn’t.

Not even close.

Conformity was rampant. Around 75 percent of participants conformed to the group at least once. And while most people didn’t conform on every trial, on average, people conformed a third of the time.

Even though people’s own eyes told them the correct answer, they went along with the group. Even when they could clearly tell that the group was incorrect.

Solomon Asch was wrong and Sherif was right. Even when the answer is clear, people still imitate others.2

Imagine a hot day. Really hot. So sweltering that the birds won’t even sing. You’re parched, so you drop into a local fast-food restaurant to grab a cold drink. You walk up to the counter and the clerk asks what you’d like.

What generic term would you use if you wanted a sweetened carbonated beverage? What would you say to the clerk? If you had to fill in the blank “I’d like a ____________, please,” how would you do it?

People’s answers depend a lot on where they grew up. New Yorkers, Philadelphians, or people from the northeastern United States would ask for a “soda.” But Minnesotans, Midwesterners, people who grew up in the Great Plains region of the country would probably ask for a “pop.” And people from Atlanta, New Orleans, and much of the South would ask for a “Coke.” Even if they wanted a Sprite.

(For fun, try ordering a Coke next time you’re in the South. The clerk will ask you what kind, and then you can tell them a Sprite, Dr Pepper, root beer, or even a regular Coke.)I

Where we grow up, and the norms and practices of people around us, shape everything from the language we use to the behaviors we engage in. Kids adopt their parents’ religious beliefs and college students adopt their roommates’ study habits. Whether making simple decisions, like which brand to buy, or more consequential ones, like which career path to pursue, we tend to do as others around us do.

The tendency to imitate is so fundamental that even animals do it.

Vervets are small, cute monkeys found mostly in South Africa. Similar in size to a small dog, they have light-grey bodies, black faces, and a fringe of white around their stomachs. The monkeys live in groups of ten to seventy individuals, with males striking out on their own and changing groups once they reach sexual maturity.

Scientists often study vervets because of their humanlike characteristics. The monkeys display hypertension, anxiety, and even social and abusive alcohol consumption. Like humans, most prefer drinking in the afternoon, rather than morning, but heavy drinkers will drink even in the morning and some will even drink until they pass out.

In one clever study, researchers conditioned wild vervets to avoid certain foods.3 Scientists gave the monkeys two trays of corn, one containing pink corn and the other blue corn. For one group of monkeys, the scientists soaked the pink corn in a bitter, repulsive liquid. For another group of monkeys, the researchers flipped the colors—blue tasted bad and pink normal.

Gradually, the monkeys learned to avoid whichever color tasted bad. The first group of monkeys avoided the pink corn while the other group avoided the blue. Just like soda in the Northeast and pop in the Midwest, local norms had been created.

But the scientists weren’t just trying to condition the monkeys, they were interested in social influence. What would happen to new, untrained monkeys who joined each group?

To see what would happen, the researchers took the colored corn away and waited a few months until new baby monkeys were born. Then, they placed trays of pink and blue corn in front of the monkeys. Except this time they removed the bad taste. Now the pink corn and the blue corn both tasted fine.

Which would the baby monkeys choose?

Pink and blue corn were just as tasty, so the baby monkeys should have gone after both. But they didn’t. Even though the infants weren’t around when one color of corn tasted bitter, they imitated the other members of their group. If their mothers avoided the blue corn, they did the same. Some babies even sat on the avoided color to eat the other, ignoring it as potential food.

Conformity was so strong that monkeys who switched groups also switched colors. Some older male monkeys happened to change groups during the study. Some moved from the Pink Avoiders to the Blue Avoiders, and vice versa. And as a result, these monkeys also changed their food preferences. Switchers adopted the local norm, eating whichever color was customary among their new group.

We might have grown up calling carbonated fizzy beverages “soda,” but move to a different region of the country and our language starts to shift. A couple years surrounded by people calling it “Coke” and we might find ourselves doing the same. Monkey see, monkey do.

A few years ago, I flew to San Francisco for a consulting project. If you’ve been to the Bay Area, you know that on any given day the climate can be quite variable. Summers tend not to be that hot and winters don’t get terribly cold. But on any particular day, it’s hard to know what you’re going to get. San Francisco can easily be 70 degrees in November and 50 degrees in July. Indeed, a famous quote about the city—commonly (but erroneously) attributed to Mark Twain—is that “the coldest winter I ever spent was a summer in San Francisco.”

My trip happened to take place in November. Since I was traveling from the East Coast, I’d brought my heavy winter coat. But as I got ready to go out that first morning in San Francisco, I faced a dilemma: Should I wear my coat or not? I checked the weather report, which suggested the temperature would be somewhere in the high 50s to low 60s, but I still wasn’t sure. That sounded right on the margin between warm and cold. How to decide?

Rather than just guessing myself, I used a time-tested trick: I looked out the window to see what other people were wearing.

When we’re not sure about the right thing to do, we look to others to help us figure it out. Imagine looking for a parking spot. After driving around for what seems like forever, you find a whole side of a street free of cars. Success! But excitement quickly turns to concern: If no one else parked here, maybe I shouldn’t, either. There might be street cleaning or some special event that makes parking there illegal.

If there are even a couple other cars parked on the street, though, the concern disappears. You feel more confident you’ve found a legitimate spot.

Trying to sort out which dog food to buy or which preschool to send your child to? Knowing what others have done provides insight into what might be best for you. Talking to other dog owners who have similar breeds will help you figure out the right food option for your dog’s size and energy level. Talking to other parents will help you figure out which schools have a good student-teacher ratio and provide the right mix of learning and play.

Just as people relied on others to help them figure out how much the light moved in the dark room, we often rely on others to provide a useful source of information that helps us make better decisions.

Using others as information sources saves us time and effort. Rather than giving Fido a new brand of food every week, or spending days reading up on the minutiae of all the preschools in the area, others provide a useful shortcut. A heuristic that simplifies decision making. If other people do it, choose it, or like it, it must be good.

But as the experiment about the length of lines demonstrates, imitation is about more than just information. Even when we know the answer, others’ behavior can still have an impact. And the reason is social pressure.

Think about going out to dinner at a nice restaurant with a group of colleagues from work. Business has been great recently, so the boss takes everyone out to celebrate. Some New American place that puts nouveau touches on old favorites. Everything from lobster mac and cheese to un-sloppy Joes made with ahi tuna instead of pork. The appetizers were good, the entrées stellar, and everyone is enjoying a fun evening of drinks and conversation.

Then the time comes to order coffee and dessert. This restaurant is known for their sweets. The key lime pie looks great, but so does the double chocolate cake. Tough choice! You decide to let someone else order first while you mull over the options.

But then something funny happens. No one else wants dessert.

Your first colleague begs off, saying she’s too full, and a second colleague says no because he’s trying to lose weight. Then, one by one, each person around the table declines.

The waiter gets to you. “Dessert?” he asks.

This situation is a lot like Asch’s line-length study. You know what you want—to order dessert, the chocolate cake and the key lime pie—just like you knew which line was the correct one. So it’s not like other people provide any useful information that helps you make a better decision. But even so, you still feel as though you should pass.

Most people like being liked. We want to be accepted or at least not excluded. If not by everyone, then at least by the people we care about. Anyone who has ever been picked last for a basketball game or left off the invite list to a wedding knows that being left out doesn’t feel good.

The same is true for ordering dessert. Sure, you could be the only one to order a tasty treat. There’s no law that says you can’t eat dessert alone. And yet you feel weird about being the only one ordering. Like people will think you’re selfish, or that you’ll stand out in a bad way.

So in most cases, people go along. They skip dessert because everyone else passed. Just to be part of the group.

But in addition to information and social pressure there’s also one more reason people conform.

Sometimes I look in the mirror and see someone else’s face staring back at me.

Most people look like a mix of their parents. Their father’s nose and their mom’s eyes. Their dad’s jawline and their mother’s hair.

When I look in the mirror, though—particularly when I’ve just gotten a haircut—I see my brother. Only five years apart, we look a lot alike. Similar facial structure, similar mouth. My hair is curlier and lighter than his, but we have a lot of the same features.

Genes obviously play a big role. If two people have the same parents, much of their genetic makeup is similar. Depending on which characteristics are expressed, siblings can end up looking like mirror images.

Genetics aren’t the only reason siblings look similar, though, because married couples actually resemble one another as well. Even though spouses aren’t related, their faces look alike. Compare two married people with two people selected at random and the married people look more similar.

Part of this similarity is driven by assortative mating. People tend to marry others of similar ages, nationalities, and racial backgrounds. Swedes tend to marry Swedes, twenty-year-olds tend to marry twenty-year olds, and South Africans tend to marry South Africans. Birds of a feather flock together, as they say.

Further, people tend to like others that look like them. If you have an oval face or prominent cheekbones, you tend to find other people with oval faces or prominent cheekbones more attractive. Just like the idea of mere exposure we talked about previously.

All this pushes people toward marrying others that look at least a little like them.

But that’s not the end of the story. Because over time, partners’ similarity heightens even more. Couples may have started out looking vaguely similar, but as the years go by, the resemblance gets even stronger. It’s like two faces morphing into one. By their twenty-fifth wedding anniversary, married people look more and more like proverbial peas in a pod.

And while one could attribute this to age, or shared environment, even controlling for these factors, married people still look more similar than one might expect.

Instead, there is a more subtle mechanism at play.4 When we feel happy, sad, or any number of other emotions, our faces contort to match our feelings. We smile when we’re happy, frown when we’re sad, and knit our eyebrows when we’re angry.

While any particular emotional expression is fleeting, years of repeated expressions leave their mark on our faces. Crow’s-feet, or the tiny wrinkles that form on the outside corners of the eyes, are often called laugh lines because of their association with smiling. It’s like folding a piece of paper. The more times you fold it, the deeper the creases become.

But our emotions are not independent. We tend to mimic, or imitate, the emotional expressions of those around us. If your friend laughs while telling a joke, you’ll probably laugh as well. And if they share a sad story, your face registers sadness too.

Emotional mimicry is particularly prevalent among married couples. Partners spend a lot of time looking at, and listening to, one another. Hearing what happened at work or empathizing over how frustrating it must have been that the store closed early.

As a result, partners don’t just share space and food, they share emotions. They laugh together, cry together, and even get angry together. We might get laugh lines from telling lots of jokes, but our partners are getting those same lines from listening. Years of making the same expressions, at the same time, leave small, but similar, traces on our faces.II Mimicry has made us look similar.

Chameleons are amazing creatures. Unlike most animals, whose eyes move in concert, a chameleon’s eyes move independently, allowing them to see almost 360 degrees. Chameleons’ tongues are equally impressive. They can be twice a chameleon’s body length and when catching prey, lash out at almost 15 miles per hour.

What chameleons are most known for, though, is their ability to change color. To shift their body coloration in response to their environment.5

Humans actually do something similar. We may not change our skin color, but we mimic the facial expressions, gestures, actions, and even language of the people around us.6

We smile when others smile, wince when we see others in pain, and say “ya’ll” when talking to a friend from Texas. If we happen to be sitting in a meeting where someone touches their face or crosses their legs, we’re more likely to touch our face or cross our legs as well. All without realizing that we’re doing it.

Mimicry starts almost from the day we’re born. Two-day-old babies cry in response to another baby’s crying7 and mimic the emotional expressions of their caregivers. Seeing someone stick out their tongue leads young kids to do the same.

And all this imitation happens nonconsciously. We don’t deliberately lean back in our chair if someone else does the same, and we don’t try to speak with a Texas drawl just because a friend does.

But even though we may not realize it, we are constantly and automatically imitating the actions of those around us. Subtly moving, posturing, and acting in ways that mirror our interaction partners. And they are doing the same for us.

The neurological underpinnings of mimicry would never have been discovered, though, if it weren’t for an ice cream cone.

One hot day in Parma, Italy, a macaque monkey sat in his cage in the corner of a neuroscience laboratory, waiting for researchers to come back from lunch. The monkey was hooked up to a big machine and thin electrodes ran from its brain, registering neural activity. The electrodes focused on the premotor cortex, a region involved in planning and initiating movement. In particular, an area related to actions involving the hands and mouth.

Every time the monkey moved its hands, or mouth, tiny related brain cells would fire, and a sound would register on a monitor.8 When the monkey raised its hand, the monitor went bliip, blip. When the monkey reached out to bring something to its mouth: bliip, bliip . . . bliip. The sound echoed through the lab.

So far, the study was going pretty much as expected. Premotor neurons were firing whenever the monkey engaged in various movements. With every action, a loud bliip emanated from the machine. The scientists left the equipment on and went to grab a bite to eat.

One of the graduate students returned eating an ice cream cone. He held the cone out in front of him, almost like a microphone.

The monkey looked on with interest. Gazing longingly at the cone.

But then something unusual happened. As the student raised the cone to his lips, the monitor went off. Bliip, blip, it sounded.

But the monkey wasn’t moving.

The grad student walked closer and again moved the ice cream toward his mouth. Bliip, bliip, screamed out the monitor. If the monkey was immobile, why were brain regions associated with planning and initiating movement firing?

Turns out that the same cells that fired when the monkey took an action were also firing when the monkey observed someone else take that action.

The cells fired when the monkey moved its hand to its mouth, but also when the monkey merely observed the grad student move the ice cream cone toward his lips. Later tests showed that the cells fired when the monkey picked up a banana, but they also fired when the monkey watched someone else pick up a banana.

The cells even fired for sounds. When the monkey cracked open a peanut but also when it heard someone else crack open a peanut. Observing someone doing something led the monkey’s brain to simulate that same action itself. The Italian scientists had discovered what we know today as “mirror neurons.”

Since that initial discovery, researchers have found mirror neurons in humans as well. Watching someone else engage in an action activates the same cortical region as engaging in that action. Watch others grab an object, and the motor-evoked potentials, or signal that a muscle is ready to move, is similar to grasping that object ourselves.9

Others can thus prime us for action. Observing others do something can activate our mind in ways that make it easier for us to do the same thing. See someone sit up straight in a meeting? Watch someone grab candy from a bowl? We may find ourselves doing the same thing because their actions primed ours. Our minds, and muscles, have been directed down a course of imitation.III

That we’re hardwired to imitate is interesting in itself, but behavioral mimicry also has important consequences. Sure, we mimic others, but what happens when others mimic us?

Jake hated negotiating. He hated it so much that he would rather pay full price for a new car than have to haggle. Bargaining for a price on eBay’s Make an Offer was enough to give him a small panic attack. Whether sorting out salary requirements at his last job or hashing out the details of a supplier contract, negotiating was something Jake would rather skip. It felt forced, confrontational, and argumentative.

Yet there he was, late one Tuesday afternoon, locked in a tense negotiation over, of all things, a gas station.

Jake had been given the role of service station owner and was facing off against Susan in an MBA class exercise on negotiation. His job was to sell his gas station at a good price.

The owner and his wife had been working eighteen-hour days the past five years to save enough money to realize their life dream: to sail around the world. They’d leave from Los Angeles, and spend two years winding through dozens of places they’d only read about in books. They’d already put a down payment on a beautiful old boat and had started fitting it out for the trip.

The only hitch was the station. They needed money to finance the trip, so would have to sell it. Jake, in his role as the station owner, was trying to unload the station fast. He had to sell it soon, but, to pay for the trip, he had to clear a certain price.

Susan sat across the table.

She had been given the role of representing Texoil, a large oil and gas company interested in buying the station. The company was in the midst of a strategic expansion and was acquiring independent service stations just like Jake’s.

Jake started the negotiation by talking about how great the station was. That it had little competition and would be a perfect investment opportunity. Plus, property values had increased over the last decade, and it would cost Texoil much more to build a comparable station from scratch.

Susan flattered Jake by talking about the valued history of the station, but countered that it would require a significant capital investment from Texoil to update. New pumps and a brand-new mechanics area. Texoil could only offer so much for the station.

As negotiators often do, each focused on the facts that made their side look good. They led with why the price should favor their position, and hid information that would hurt their cause.

Eventually, they started tossing out numbers.

Susan offered $410,000. Jake politely declined, and came back with $650,000. Susan budged up a