The need to belong may be the most powerful of all human motivations. It makes good evolutionary sense because, like apes, bees, and elephants, human beings could never have survived without being a part of a tribe. The need for connection explains why sending a prisoner to solitary confinement is considered a form of torture: Its psychological consequences are even more devastating than physical abuse (Gawande, 2009). (And it's also why some parents use removal of their teenager's cell phone as a form of punishment!) In fact, the social pain of being excluded, rejected, or humiliated activates parts of the brain that are highly diagnostic of physical pain (Chen et al., 2008; DeWall & Bushman, 2011; Eisenberger, Lieberman, & Williams, 2003; Williams, 2009). Social rejection also impedes the ability to empathize, think critically, and solve problems and can lead to mental disorders, eating disorders, and attempted suicide. Conversely, social acceptance, a sense of belonging, can have many positive effects. For example, minority students who feel that they belong in school have better grades, health, and well-being (Walton & Cohen, 2011).

Of course, we belong to many different groups, which vary in their importance to us. But the point to underscore is that as soon as we join a bunch of other people, we act differently than we would on our own. This change occurs regardless of whether the group has convened to solve problems and make decisions, has gathered to have a party, consists of anonymous bystanders, or is a crowd of spectators. In this section, we will look at the many ways the presence of other people can affect our own behavior.

Suppose that you are required to appear at a psychology laboratory for an experiment on perception. You join seven other students seated in a room. You are shown a 10-inch line and asked which of three other lines is identical to it. The correct answer, line A, is obvious, so you are amused when the first person in the group chooses line B. “Bad eyesight,” you say to yourself. “He's off by 2 whole inches!” The second person also chooses line B. “What a dope,” you think. But by the time the fifth person has chosen line B, you are beginning to doubt yourself. The sixth and seventh students also choose line B, and now you are worried about your eyesight. The experimenter looks at you. “Your turn,” he says. Do you follow the evidence of your own eyes or the collective judgment of the group?

Asch's Line-Judging Experiment

This was the design for a series of famous studies of conformity conducted by Solomon Asch (1952, 1965). The seven “nearsighted” students were actually Asch's confederates. Asch wanted to know what people would do when a group unanimously contradicted an obvious fact. He found that when people made the line comparisons on their own, they were almost always accurate. But in the group, only 20 percent of the students remained completely independent on every trial, and often they apologized for not agreeing with the others. One-third conformed to the group's incorrect decision more than half the time, and the rest conformed at least some of the time. Whether or not they conformed, the students often felt uncertain of their decision. As one participant later said, “I felt disturbed, puzzled, separated, like an outcast from the rest.” Asch's experiment has been replicated many times and in many countries over the years (Bond & Smith, 1996).

There are two basic motives for conformity, and, remarkably, both motives appear in many other species, from rats to primates, suggesting that conformity has a powerful adaptive function (Claidière & Whiten, 2012). One is the need for social acceptance, which is the reason that people can end up doing all kinds of stupid things (or smart things!) simply because their friends are doing them. By understanding the power of this motive, social psychologists have designed interventions to rally people's peer groups to help them stop smoking and binge drinking, stay in school and improve their performance, and make many other beneficial changes they would not do on their own (Wilson, 2011).

The second reason for conformity is the need for information before deciding on the “right” thing to do (Cialdini, 2009). People often intuitively understand that sometimes the group knows more than they do, and this reliance on group judgment begins in very early childhood. When 3- and 4-year-old children were given a choice between relying on information provided by a three-adult majority or a single adult about the name of an unfamiliar object, they sided with the majority (Corriveau, Fusaro, & Harris, 2009). It works the same way with adults: The belief that “everyone else” is doing something must mean it is the wisest choice or course of action. Again, social psychologists have used this knowledge to induce people to make improvements. When hotels put notices in guest bathrooms saying that “the majority of guests in this room reuse their towels” (in contrast to simply requesting the guest to do the same because it's good for the environment), the number who participate in the reuse program rises markedly (Goldstein, Cialdini, & Griskevicius, 2008).

Like obedience, therefore, conformity has positive aspects. Society runs more smoothly when people feel that they belong, know how to behave in a given situation, and share the same norms. But also like obedience, conformity has negative consequences, notably its power to suppress critical thinking and creativity. In a group, many people will deny their private beliefs, agree with silly notions, and even repudiate their own values—just to be accepted.

Close, friendly groups usually work well together. But they face the problem of getting the best ideas and efforts from their members while avoiding an extreme form of conformity called groupthink, the tendency to think alike and suppress dissent. According to Irving Janis (1982, 1989), groupthink occurs when a group's need for total agreement overwhelms its need to make the wisest decision. The symptoms of groupthink include the following:

• An illusion of invulnerability. The group believes it can do no wrong and is 100 percent correct in its decisions.

• Self-censorship. Dissenters decide to keep quiet rather than make trouble, offend their friends, or risk being ridiculed.

• Pressure on dissenters to conform. The leader teases or humiliates dissenters or otherwise pressures them to go along.

• An illusion of unanimity. By discouraging dissent and failing to consider alternative courses of action, leaders and group members create an illusion of consensus; they may even explicitly order suspected dissenters to keep quiet.

Throughout history, groupthink has led to disastrous decisions in military and civilian life. In 1961, President John F. Kennedy and his advisers approved a CIA plan to invade Cuba at the Bay of Pigs and try to overthrow the government of Fidel Castro; the invasion was a humiliating defeat. In 1986, NASA officials insulated themselves from the dissenting objections of engineers who warned them that the space shuttle Challenger was unsafe; NASA launched it anyway, and it exploded shortly after takeoff. And when, in 2003, President George W. Bush launched an invasion of Iraq, claiming the country had weapons of mass destruction and was allied with al-Qaeda, he and his team ignored dissenters and evidence from intelligence agencies that neither claim was true (Mayer, 2009). The agencies themselves later accused the Bush administration of “groupthink.”

Fortunately, groupthink can be minimized if the leader rewards the expression of doubt and dissent, protects and encourages minority views, asks group members to generate as many alternative solutions to a problem as they can think of, and has everyone try to think of the risks and disadvantages of the preferred decision. Resistance to groupthink can also be fostered by creating a group identity that encourages members to think of themselves as open-minded problem solvers rather than invulnerable know-it-alls (Turner, Pratkanis, & Samuels, 2003). Leaders who encourage group members to identify strongly with the collective enterprise are also more likely to hear dissenting opinions because members will be less willing to support a decision they regard as harmful to the group's goal (Packer, 2009).

Not all leaders want to run their groups this way, of course. For many people in positions of power, from presidents to company executives to movie moguls, the temptation is great to surround themselves with others who agree with what they want to do, and to demote or fire those who disagree on the grounds that they are being “disloyal.” Perhaps a key quality of great leaders is that they are able to rise above this temptation.

Many popular websites offer some variation on the “you might also like” theme. Whether you're downloading a book or buying a song, chances are you'll get a message highlighting the recommendations and preferences of other people who've purchased the same item. This strategy comes straight from a phenomenon known as the “wisdom of crowds”: the fact that a crowd's judgment is often more accurate than that of its individual members—a reason for conformity, as we noted earlier (Surowiecki, 2004; Vul & Pashler, 2008). Just as neurons interconnect in networks that create thoughts and actions beyond the scope of any individual cell, so does a crowd create a social network whose “behavior” is more than individual members may intend or even be aware of (Goldstone, Roberts, & Gureckis, 2008; Wegner, 1986). But crowds can create havoc, too. They can spread gossip, rumors, misinformation, and panic as fast as they can share recommendations for your Netflix queue. They can turn from joyful and peaceful to violent and destructive in a flash.

Deindividuation The most extreme instances of the diffusion of responsibility occur in large, anonymous mobs or crowds. The crowds may consist of cheerful sports spectators or angry rioters. Either way, people often lose awareness of their individuality and seem to hand themselves over to the mood and actions of the crowd, a state called deindividuation (Festinger, Pepitone, & Newcomb, 1952). You are more likely to feel deindividuated in a large city, where no one recognizes you, than in a small town, where it is hard to hide. (You are also more likely to feel deindividuated in large classes, where you might—mistakenly!—think you are invisible to the teacher, than in small ones.) Sometimes organizations actively promote the deindividuation of their members to enhance conformity and allegiance to the group. This is an important function of uniforms or masks, which eliminate each member's distinctive identity.

Deindividuation has long been considered a prime reason for mob violence. According to this explanation, because deindividuated people in crowds “forget themselves” and do not feel accountable for their actions, they are more likely to violate social norms and laws—breaking store windows, looting, getting into fights, or rioting at a sports event—than they would be on their own. But deindividuation does not always make people more combative. Sometimes it makes them more friendly; think of all the chatty, anonymous people on buses and planes who reveal things to their seatmates they would never tell anyone they knew.

What really seems to be happening when people are in large crowds or anonymous situations is not that they inevitably become mindless or aggressive. Rather, they become disinhibited, just as if they were intoxicated on alcohol. That disinhibition, in turn, makes them more likely to conform to the norms of the specific situation, which may be either antisocial or prosocial (Hirsh, Galinsky, & Zhong, 2011; Postmes & Spears, 1998). College students who go on wild sprees during spring break may be violating the local laws and norms not because their aggressiveness has been released but because they are conforming to the “Let's party!” norms of their fellow students. Crowd norms can also foster helpfulness, as they often do in the aftermath of disasters, when strangers come out to help victims and rescuers, leaving food, clothes, and tributes. And so, should the deindividuation excuse, like the “I was only following orders” excuse, exonerate a person of responsibility for looting, rape, or even murder? What do you think?

The Presence of Others Affects Our Behavior

We have seen how roles, norms, and pressures to obey authority and conform to one's group can cause people to behave in ways they might not otherwise. Yet throughout history, men and women have disobeyed orders they believed to be wrong and have gone against prevailing cultural beliefs; their actions have sometimes changed the course of history. In 1955, in Montgomery, Alabama, a shy, quiet woman named Rosa Parks refused to give up her bus seat to a white passenger, and she was arrested for breaking the law. Her protest sparked a 381-day bus boycott and helped launch the modern civil rights movement.

Sadly, the costs of dissent, courage, and honesty are often high; remember that most groups do not welcome deviance, nonconformity, and disagreement. Most whistle-blowers, far from being rewarded for their bravery, are punished for it. Three women were named Time magazine's Persons of the Year for their courage in exposing wrongdoing in their respective organizations—Enron, WorldCom, and the FBI—yet all paid a steep professional price for doing so. In fact, studies of whistle-blowers find that half to two-thirds lose their jobs and have to leave their professions entirely. Many lose their homes and families (Andrade, 2015).

Could You Be a Hero?

Nonconformity, protest, and altruism, the willingness to take selfless or dangerous action on behalf of others, are in part a matter of personal convictions and conscience. However, just as there are situational reasons for obedience and conformity, there are external influences on a person's decision to state an unpopular opinion, choose conscience over conformity, or help a stranger in trouble. Here are some of the situational factors that can overcome bystander apathy and increase the likelihood of helping others or behaving courageously:

1. You perceive the need for intervention or help. It may seem obvious, but before you can take independent action, you must realize that such action is necessary. Sometimes people willfully blind themselves to wrongdoing to justify their own inaction (“I'm just minding my business”; “I have no idea what they're doing over there at that concentration camp”). But blindness to the need for action also occurs when a situation imposes too many demands on people's attention, as it often does for residents of densely populated cities.

2. Cultural norms encourage you to take action. Would you tell a passerby that he or she had dropped a pen? Offer to help a person with an injured leg who had dropped an armful of magazines? Assist a blind person across the street? An international field study investigated strangers' helpfulness to one another with those three nonemergency acts of kindness, in 23 U.S. cities and 22 cities in other countries. Cultural norms for helping were more important than population density in predicting levels of helpfulness: Pedestrians in busy Copenhagen and Vienna were kinder to strangers than were passersby in busy New York City. Helping rates ranged from 93 percent in Rio de Janeiro, Brazil, to 40 percent in Kuala Lumpur, Malaysia (R. Levine, 2003; Levine, Norenzayan, & Philbrick, 2001).

3. You have an ally. In Asch's conformity experiment, the presence of one other person who gave the correct answer was enough to overcome agreement with the majority. In Milgram's experiment, the presence of someone who disobeyed the experimenter's instruction to shock the learner sharply increased the number of people who also disobeyed. One dissenting member of a group may be viewed as a troublemaker, but two or three are a coalition. An ally reassures a person of the rightness of the protest, and their combined efforts may eventually persuade the majority (Wood et al., 1994).

4. You become entrapped. Does this sound familiar by now? Having taken the initial step of getting involved, most people will increase their commitment. In one study, nearly 9,000 federal employees were asked whether they had observed wrongdoing at work, whether they had told anyone about it, and what happened if they had told. Nearly half of the sample had observed some serious cases of wrongdoing, such as stealing federal funds, accepting bribes, or creating a situation that was dangerous to public safety. Of that half, 72 percent had done nothing at all, but the other 28 percent reported the problem to their immediate supervisors. After they had taken that step, a majority of the whistle-blowers eventually took the matter to higher authorities (Graham, 1986).

As you can see, certain social and cultural factors make altruism, disobedience, and dissent more likely to occur, just as other external factors suppress them.