Human behavior in groups is shaped both by the identities people share and by the models they observe. These theories show why social contexts can produce, maintain, and change behavior.

Social Identity Theory

One major explanation of behavior in groups is social identity theory.

People do not act only as isolated individuals. In many situations, they think of themselves as members of a group, such as a nationality, sports team, school, religion, or friendship circle. When a group identity becomes important, people are more likely to follow group norms, defend the group, and compare their group with others.

Core processes in social identity theory

Social identity theory is usually explained through three linked processes:

Flowchart of Tajfel & Turner’s social identity theory showing how social categorization leads to distinct “we” (in-group) vs. “they” (out-group) group boundaries, followed by intergroup comparison. It visually links these cognitive steps to outcomes such as more favorable evaluations of the in-group and changes in satisfaction with one’s social identity. Source

• Social categorization: placing people, including ourselves, into groups

• Social identification: adopting the identity and expected behavior of a group we belong to

• Social comparison: comparing our group with other groups

These processes can produce in-group favoritism, where people prefer or support their own group, even when group divisions are weak or arbitrary. Tajfel’s minimal group studies showed that simply assigning people to groups could lead them to favor their own group.

Example of the point-allocation matrices used in Tajfel’s minimal group paradigm. These matrices operationalize in-group favoritism by forcing participants to choose distributions of rewards between an in-group member and an out-group member, making bias measurable even when group membership is trivial. Source

This suggests that shared identity alone can shape behavior.

A key idea is that people often want a positive social identity. If their group is seen positively, self-esteem may increase. As a result, people may act in ways that protect group status, copy group norms, or reject behaviors linked to an out-group. This helps explain behavior in school cliques, political groups, workplaces, and online communities.

Social identity theory also helps explain behavior change. If group norms change, individual behavior often changes with them. For example, if a peer group begins to value recycling, respectful language, or healthy habits, members may adjust their behavior to fit the group standard. In this way, social influence works through identity, not only through direct pressure.

Social Learning Theory

A second explanation of behavior in social settings is social learning theory.

This theory emphasizes that much human learning is observational. People do not need to experience reward or punishment directly. Instead, they can watch what happens to others and learn from those outcomes. This is called vicarious reinforcement when seeing another person rewarded makes imitation more likely, and vicarious punishment when seeing another person punished makes imitation less likely.

Conditions that make observational learning more likely

Diagram summarizing Bandura’s four stages of observational learning: attention, retention, reproduction, and motivation. It organizes the cognitive “mediators” between seeing a model’s behavior and later performing (or inhibiting) that behavior, which helps explain vicarious reinforcement and punishment. Source

Imitation is more likely when:

• the model is seen as similar, high status, or attractive

• the observer pays attention to the behavior

• the behavior can be remembered

• the observer feels able to reproduce it

• the social context provides motivation to perform it

Bandura’s research on children and aggressive models showed that children can copy behavior they observe, especially when the model appears successful or unpunished. This was important because it showed that social contexts, including families, peers, and media, can transmit behavior patterns.

Social learning theory does not claim that people copy everything they see. Cognitive processes matter. A person may learn a behavior without performing it immediately. Performance depends on motivation, expectations, and whether the situation allows the behavior. This helps explain why different people respond differently to the same social model.

Using These Theories to Change Behavior

Both theories are valuable because they do not just explain behavior; they suggest ways to change it.

Applying social identity theory

Behavior change is often stronger when a message is tied to a meaningful shared identity. People may resist instructions from an out-group but accept the same message from an in-group leader. Because of this, psychologists and campaign designers often try to:

• use respected in-group messengers

• present desired behavior as part of “who we are”

• reshape group norms so the new behavior becomes expected

• create broader identities that reduce conflict between groups

For example, a school may reduce bullying more effectively by promoting a shared school identity that values inclusion, rather than only punishing individuals. Similarly, health campaigns can be more persuasive when they connect behavior to a valued group identity, such as “responsible teammates” or “caring families.”

Applying social learning theory

Social learning theory suggests that behavior change is more likely when people can see clear, credible models performing the target behavior. Useful strategies include:

• showing prosocial models demonstrating the behavior

• making positive consequences visible

• using peers, teachers, parents, or media figures as role models

• reinforcing the behavior after imitation

This approach is widely used in education, parenting, health promotion, and aggression prevention. For instance, if children repeatedly observe calm conflict resolution being rewarded, they are more likely to adopt that response themselves.

The two theories can also work together. People are especially likely to imitate a model when that model belongs to a group they identify with. This means social identity can shape who influences us, while social learning helps explain how that influence changes behavior.