The study of peer influence has an important place in the social sciences, particularly in social psychology and developmental psychology. In a now classic series of studies conducted in the 1950s, Solomon Asch (1907-1996), a Polish-born American social psychologist, showed groups of eight to ten college students a set of three lines that differed clearly in length and asked them to indicate out loud which of the three lines was the same length as a fourth line. Only one of the group members was an actual experiment participant; the other group members were associates of the experimenter who were trained to respond incorrectly about the length of the line. In scenarios when the other group members provided unanimously incorrect responses, the experiment participants voiced the same opinion as the other group members one-third of the time. When they were later asked why they responded as they did, the experiment participants generally stated that they knew the group members were wrong in their choice of the matching line but said that they did not want to be ridiculed, ostracized, or thought peculiar by the rest of the group if they gave an opinion that went against the majority view. The many variants of Asch’s experiments have been taken as evidence that peers exert considerable influence on the behavior of one another.
One of the difficulties that studying peer influence has encountered is the question of whether peers actually do influence one another or whether individuals who are similar to one another simply seek each other out. Although there is evidence that young people who engage in deviant behaviors seek out peers who also engage in deviant behaviors, studies that have been able to control for the effects of peer selection have shown that once deviant peers are together in a group, they do incrementally increase one another’s engagement in deviant behavior (e.g., Matsueda and Anderson 1998).
NEGATIVE PEER PRESSURE AND POSITIVE PEER INFLUENCE
When thinking of peer influence, what comes readily to mind for most people is negative peer pressure. For example, parents, teachers, and other adults worry that adolescents will be pressured by their peers to smoke cigarettes, drink alcohol, have sexual intercourse, or engage in risky behaviors. Indeed, peers can and do influence one another to behave in more deviant ways. In several studies, the best predictor of whether an adolescent will engage in antisocial behavior has been found to be whether he or she affiliates with peers who engage in antisocial behavior (see Pratt and Cullen 2000).
On the other hand, peer influence can also be positive. For example, adolescents can study together, encourage each other to join an extracurricular activity, or provide a fun peer context that does not promote using drugs or engaging in risky behaviors. In fact, the premise of peer mentoring programs is that being paired with a well-adjusted peer can be a positive influence on a youth who is at risk for behavioral or psychological problems.
MECHANISMS OF PEER INFLUENCE
Several influential theories have attempted to explain how peers influence one another. Reinforcement theories emphasize that peers exert influence because they control (consciously or not) rewards that are meaningful. Individuals will behave in ways that are likely to maximize their rewards. Therefore, if an individual perceives that engaging in behavior promoted by peers will result in desired outcomes (e.g., acceptance by the group, high status, access to material possessions), he or she will be more influenced by peers.
Psychologist Thomas J. Dishion’s work on deviancy training has led to a better understanding of the mechanisms through which peers reinforce one another’s behavior during social interactions. Adolescent boys were observed with their best friend in a laboratory setting. The interactions were coded for whether one boy provided positive responses (such as laughter) when the other boy talked about deviant behavior. Boys whose interactions were characterized by this process of deviancy training were found to engage in subsequently higher levels of substance use, violence, and delinquency, even controlling for previous levels of problem behaviors (e.g., Dishion et al. 1996). Nondeviant boys typically ignored rather than reinforced deviant talk.
Modeling is another mechanism that has been proposed to explain how peers influence one another in either positive or negative ways. Peer mentoring programs often count on this mechanism as mentors model prosocial behavior in the hope of eliciting prosocial behavior from their mentees. On the other hand, observing others engage in deviant behaviors might lift an adolescent’s own inhibitions against behaving deviantly. For example, if adolescents observe that many of their classmates drink alcohol or skip school, a given adolescent may feel that social barriers against his or her own drinking or skipping school have been lifted. Fads in clothing or music preferences can also be explained through the mechanism of modeling, which can occur not just between individuals but also at the level of entire schools or neighborhoods.
INDIVIDUAL DIFFERENCES IN SUSCEPTIBILITY TO PEER INFLUENCE
Not all individuals are equally susceptible to peer influence. Age is a key factor that relates to individuals’ susceptibility to peer influence. Peer influence begins in the preschool years and increases in importance over time, generally peaking in early adolescence before decreasing as individuals enter later adolescence. Not only does the power of peer influence change with development, the outcomes that peers influence are likely to change as well. For example, peer influence has been found to affect aggression among preschoolers, aggression and covert antisocial behavior among children in elementary school, and substance use and sexual behaviors among adolescents.
In addition to age, other individual differences may contribute to susceptibility to peer influence as well. For example, youth who have a history of being rejected by their peers are more susceptible to later negative peer pressure than are youth who have a history of being accepted by their peers. Youth who have positive, supportive relationships with adults are also less susceptible to influence by their peers than are youth who are not positively connected with adults. Temperamental characteristics, such as the ability to self-regulate, may also contribute to one’s susceptibility to peer influence. Research suggests that youth who have already begun to experiment with deviant behaviors are the most susceptible to peer influence toward further deviance. In contrast, youth who are already heavily involved in deviant behavior likely do not need additional peer influence to keep them on this path, and youth who are strongly oriented against deviant behavior may be able to resist negative peer pressure. Social contexts can also alter the extent to which peers exert influence on one another. For example, in social situations that are unstructured and unsupervised by adults, adolescents are more susceptible to peer influence than they are in more structured and supervised contexts.
To summarize, despite the ability of peers to influence one another in negative ways, peers can also influence one another positively. Mechanisms through which peers influence one another include reinforcement, deviancy training, and modeling. Furthermore, not all individuals are equally susceptible to peer influence. This entry has focused on peer influence during adolescence because it is at this age when individuals are the most susceptible to peer influence; however, as Asch’s pioneering work demonstrated, peer influence persists into adulthood and can lead individuals to act in ways contrary to how they would be expected to behave in the absence of peers.