Apply social identity theory to explain intergroup conflict, prejudice and helping, and evaluate how contact, superordinate goals and recategorisation can change group behaviour.
Each is in the Psychology glossary, with every other term in the subject.
A model of prejudice reduction proposing that recategorising members of two groups as one larger shared group reduces bias between them.
The proposal that contact between members of different groups reduces prejudice, especially under conditions of equal status, shared goals, cooperation and support from authorities.
The process of perceiving or treating members of a group as less than fully human, which weakens moral restraints on harming them.
Unfair behaviour towards a person because of their membership of a particular group, such as excluding, harming or giving fewer resources to them.
Hostility, competition or aggression between groups, in which people act as group members rather than as individuals.
A negative attitude towards members of a group based on their group membership, made up of beliefs (stereotypes), feelings and readiness to act.
A theory proposing that hostility between groups arises when they compete for limited resources, and is reduced when they work together towards shared goals.
A goal that two or more groups want but can achieve only by cooperating with each other.
Explain how social identity theory accounts for group behaviours such as intergroup conflict, prejudice, discrimination and helping.
Explain prejudice, discrimination and dehumanisation, and the conditions under which in-group favouritism turns into intergroup conflict.
Compare and contrast social identity theory and realistic conflict theory as explanations of intergroup conflict, using the Robbers Cave study.
Explain how social identity theory can be applied to change group behaviour through contact, superordinate goals and recategorisation.
Describe and evaluate Mousa’s (2020) field experiment on intergroup contact in post-conflict Iraq.
Discuss how biological, cognitive and sociocultural factors interact in intergroup behaviour.
Evaluate attempts to change intergroup behaviour with reference to change, causality, measurement and responsibility.
Many of the most serious problems between people are problems between groups: discrimination against ethnic or religious minorities, violence between rival fans, and conflict between communities after a war. Social identity theory explains how such group behaviour arises from ordinary processes of categorising and identifying with groups, and it suggests how the same processes can be used to reduce conflict.
In the human relationships context, the theory is applied to group behaviour: how people act towards members of their own and other groups, and how those relations can be changed. The research draws on the sociocultural approach (group norms, history and status), the cognitive approach (categorisation and how categories can be changed) and the biological approach (emotional responses to threat and to in-group and out-group members). Because the aim is often to improve relations, the concept of
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Social identity theory, proposed by Tajfel and Turner in 1979, holds that part of a person’s self-concept comes from the groups they belong to. Through social categorisation people sort others into an in-group and out-groups; through social identification they take on the identity and norms of their group; and through social comparison they evaluate their group against others. The wish for positive distinctiveness leads to in-group favouritism. In the minimal group experiments, schoolboys favoured their own group even when the groups were random and trivial.
Self-categorisation theory adds that which identity guides behaviour depends on the situation: the same person can act as an individual, as a member of one group or as a member of a larger shared category. This flexibility is the key to applying the theory to change, because if bias depends on which categories are salient, changing the categories should change the behaviour.
In-group favouritism on its own is mild: people like, trust and help their own group a little more. Social identity theory also explains how favouritism can become more harmful forms of group behaviour, and under what conditions.
Prejudice is an attitude; discrimination is behaviour. The two often go together, but not always: a person may hold prejudiced views without acting on them because norms forbid it, or may discriminate by following an institutional rule without holding a prejudiced attitude. When group members act towards another group with hostility, competition or aggression, as group members rather than as individuals, the result is intergroup conflict.
Social identity theory identifies several conditions that make the move from favouritism to hostility more likely.
Threat to the in-group. When the group’s status, values or safety seem threatened, identification strengthens and the out-group is seen more negatively.
Strong identification. People who identify strongly with a group are more affected by its successes and failures, so they are more motivated to defend its position.
Illegitimate, unstable status differences. When a low-status group sees its position as unfair and changeable, social competition, including protest or conflict, becomes likely; a high-status group that feels its position is threatened may respond with hostility.
Group norms. If the in-group’s norms approve of hostility to the out-group, members conform to them. If norms reject prejudice, favouritism tends to stay mild.
In the most serious conflicts, out-group members may be seen as less than fully human. Dehumanisation weakens the moral rules that normally stop people from harming others. Kteily et al. (2015) developed a direct measure in which participants rated how “evolved” different groups were, using the familiar picture of human evolution as a scale. Across seven studies in three countries, blatant dehumanisation of out-groups predicted support for aggressive actions, such as torture and retaliatory violence, beyond the effect of prejudice, and it rose sharply after terrorist attacks.
Dehumanisation can be seen as the most extreme outcome of the comparison process, in which the out-group is judged as less human as well as worse. Because the measure is correlational, it cannot show that dehumanisation causes support for violence; violence may also lead people to justify it by dehumanising its targets.
Social identity also shapes positive group behaviour. Levine et al. (2005) studied football fans in England. In the first study, fans of Manchester United were made to think about their club, then walked to another building and saw a stranger fall and hurt himself. The stranger was more likely to be helped when he wore a Manchester United shirt than when he wore a Liverpool shirt or a plain sports shirt.
In the second study, fans were made to think about being football fans in general. Now the stranger in a Liverpool shirt was helped as well, but the stranger in a plain shirt was still helped less.
The study shows that who counts as “us” decides who is helped, and that the boundary can be moved. When a more inclusive identity was made salient, former rivals were included in the in-group. This is the same principle that interventions for reducing conflict try to use.
Realistic conflict theory explains intergroup conflict by competition for limited resources such as land, jobs or prizes. When one group can gain only if another loses, hostility develops; when groups depend on each other to reach a goal, hostility falls. The theory comes from field experiments by Muzafer Sherif and colleagues at boys’ summer camps in the United States in the 1950s.
In the best-known study, at Robbers Cave State Park in Oklahoma in 1954, 22 white, middle-class, Protestant boys aged 11–12 who did not know each other were divided into two groups and taken to the camp separately. In the first stage each group bonded, chose a name (the Eagles and the Rattlers) and developed its own norms. In the second stage the groups competed in a tournament for prizes, and hostility grew quickly: name-calling, raids on each other’s cabins and the burning of a flag. Friendship choices were almost all within the in-group.
In the third stage the researchers first tried simple contact, such as shared meals and films, which did not reduce hostility and sometimes led to food fights. They then created problems that both groups needed to solve together, such as a blocked water supply, pooling money to hire a film and pulling a stuck supply truck. After a series of these superordinate goals, hostility fell, and many more friendships crossed group lines.
The study supports realistic conflict theory: competition produced hostility, and interdependence reduced it. It also contains evidence for social identity theory, because the boys began to show favouritism and rivalry as soon as they learned the other group existed, before the tournament began, which suggests that categorisation started the rivalry and competition then intensified it.
Later research by Perry (2018), drawing on Sherif’s own archives and interviews with former participants, complicated the story. An earlier study at Middle Grove in New York in 1953 had been abandoned after the boys failed to become hostile in the way the researchers expected, and instead suspected that the adults were manipulating them. At Robbers Cave, the staff, who posed as camp workers, shaped events more than the published account suggests. The deception of children and parents, and the deliberate creation of conflict between children, would not be acceptable today.
Realistic conflict theory | Social identity theory | |
|---|---|---|
Cause of conflict | Competition for limited resources | Categorisation and the wish for a positive social identity |
How to reduce conflict | Superordinate goals that make groups interdependent | Change the categories: recategorise, decategorise or create a dual identity |
Strength | Explains why conflict is fiercer over scarce, valued resources | Explains bias between groups that do not compete |
Limitation | Cannot explain favouritism in minimal groups | Says less about when material interests drive conflict |
The two theories are complementary: competition gives social comparison something concrete to be about, and superordinate goals work partly because they change how group members categorise each other.
YouTubeIf intergroup bias depends on how people categorise themselves and others, then changing the categories, or the relations between groups, should change behaviour. Three linked strategies have strong research support: contact under the right conditions, cooperation towards superordinate goals, and recategorisation.
The contact hypothesis, proposed by Gordon Allport in 1954, states that contact between members of different groups reduces prejudice, especially under four conditions: equal status within the situation, common goals, cooperation rather than competition, and support from authorities, law or custom. Contact is thought to work by reducing anxiety about the out-group, increasing empathy and providing information that contradicts stereotypes.
Pettigrew and Tropp (2006) carried out a meta-analysis of 515 studies with 713 independent samples. Intergroup contact was reliably associated with lower prejudice. The effects were not explained by more tolerant people choosing to have contact or by publication bias, and they generalised from the individuals met to the out-group as a whole. Contact that met Allport’s conditions had larger effects, but the conditions were not essential.
Finding of the meta-analysis | What it means |
|---|---|
515 studies, 713 independent samples | A very large evidence base, across many groups and settings |
Mean correlation between contact and prejudice about r = −0.21 | More contact goes with less prejudice; the effect is moderate in size |
More rigorous studies showed larger effects | The finding is not an artefact of weak research |
Allport’s conditions increased the effect but were not essential | The conditions work best as a bundle that strengthens contact |
Effects extended to the out-group as a whole | Contact with a few individuals can change attitudes to the whole group |
Sources: Pettigrew, T. F. and Tropp, L. R. (2006). A meta-analytic test of intergroup contact theory. _Journal of Personality and Social Psychology, 90(5), 751–783._
Tropp and Pettigrew (2005) also found that contact was more strongly linked to the emotional side of prejudice, such as liking and trust, than to its cognitive side, such as stereotypes. Contact may change how people feel about an out-group before it changes what they believe about it.
YouTubeSuperordinate goals can be built into everyday settings. In the jigsaw classroom, developed by Aronson in desegregated schools in Texas in the 1970s, students work in small mixed groups in which each student holds one piece of the material that everyone needs to learn. Success depends on listening to every member, so cooperation replaces competition. Aronson and Bridgeman (1979) reported that this structure increased students’ self-esteem, liking for classmates across ethnic lines and empathy, and improved minority students’ performance without harming majority students’ performance.
The common in-group identity model, developed by Gaertner, Dovidio and colleagues in the 1990s, applies self-categorisation theory directly. If members of two groups can be led to see themselves as members of one larger group, former out-group members become in-group members, and in-group favouritism now benefits them. Recategorisation can be encouraged by shared goals, a shared fate, common symbols or a shared threat.
Vezzali et al. (2015) tested the model after the earthquakes that struck northern Italy in 2012. Among 517 primary-school children, Italian children who saw the earthquake as a serious external threat were more likely to see Italians and immigrants as one group, and this “one group” perception was linked to more positive attitudes towards immigrant children and more willingness to help them. The study is correlational, so it shows an association that fits the model rather than proving its cause.
Recategorisation has limits. People who identify strongly with their original group may resist an identity that seems to erase it, and minority groups may see a single shared identity as pressure to assimilate to the majority. A dual identity, in which the subgroup identities are kept within the shared one (“Christian and Muslim members of the same team”), is often more acceptable and allows positive attitudes to generalise to the out-group as a whole, because its members are still recognised as out-group members.
Most contact research uses questionnaires, short laboratory meetings or groups with little history of violence. Mousa’s study is one of the few true experiments to test whether contact can change behaviour between groups after a real and violent conflict.
Mousa aimed to find out whether positive contact with members of an out-group, in a cooperative setting, could improve the attitudes and behaviour of members of one community towards another after a war. The setting was northern Iraq, where many Christians had been displaced by the Islamic State group (ISIS), and relations between Christians and Muslims had been badly damaged.
The study was a field experiment built into an amateur football league organised for the research. The participants were Christian men who had been displaced by ISIS and who played football in local teams. Christian players were randomly allocated either to an all-Christian team (the control condition) or to a team that also included Muslim players (the treatment condition). The teams then played a league season under normal conditions, so contact took place within teams working towards a shared goal: winning matches.
The researchers measured outcomes in two kinds of setting. Within the league and football, they recorded behaviour towards Muslims: whether Christian players voted for a Muslim player from another team to receive a sportsmanship award, whether they signed up for a mixed team the following season, and whether they were training with Muslims six months later. Outside football, they measured behaviour in other social settings, such as whether players went to a restaurant in Muslim-majority Mosul or attended a mixed social event, as well as attitudes towards Muslims by survey. The analysis plan was registered in advance.
Outcome | Christian players with Muslim team-mates, compared with all-Christian teams |
|---|---|
Voted for a Muslim player (not on their own team) to receive the sportsmanship award | More likely |
Registered for a mixed team the next season | More likely |
Training with Muslims six months after the intervention | More likely |
Visited a restaurant in Muslim-majority Mosul | No substantial difference |
Attended a mixed social event | No substantial difference |
Attitudes towards Muslims in general (survey) | No consistent effect |
Sources: Mousa, S. (2020). Building social cohesion between Christians and Muslims through soccer in post-ISIS Iraq. _Science, 369(6505), 866–870._
Cooperative contact in a shared team improved behaviour towards Muslim peers within the setting where contact happened, and the effect lasted at least six months. It did not, however, spread to behaviour in other social settings or to general attitudes. Contact built tolerance towards the people met and the activity shared, but building wider cohesion between the communities was much harder.
In terms of social identity theory, being team-mates created a shared in-group (the team) that included Muslim players, so in-group favouritism now worked in their favour within football. The broader identities “Christian” and “Muslim”, shaped by recent violence, remained salient outside it.
Because Christian players were randomly assigned to mixed or all-Christian teams, differences between the conditions can be attributed to the contact rather than to the kind of player who chooses mixed teams, a problem that weakens most correlational contact research. Pre-registering the outcomes reduced the risk that the researchers selected only the results that supported their hypothesis. This makes the study unusually strong evidence that contact causes changes in behaviour.
Most contact studies measure attitudes by questionnaire, which are open to social desirability. Mousa measured real behaviour (votes, registrations, training, visits), which gives the conclusions more ecological validity. The difference between the strong effects within football and the absent effects outside it shows why measuring several kinds of outcome matters: a study measuring only behaviour in the league would have overestimated what contact achieved.
The participants were men who played football, in one region and one post-conflict setting, and only the Christian players’ behaviour was the focus. Women, people who do not play sport and communities with different histories might respond differently. The findings are therefore highly credible for this setting but cannot simply be transferred to other conflicts.
Research with displaced people after violence involves vulnerable participants, and placing members of groups in conflict together carries risks of harm. Running the intervention as a real, valued activity (a football league) and measuring behaviour without deception reduces these costs. The study also raises questions about responsibility in applying findings: claims that sport “builds peace” should be limited to what the evidence supports.
Online platforms make group identities visible and constantly salient. Brady et al. (2017) analysed more than 560,000 social media messages about three politically divisive issues. Each additional moral-emotional word in a message, such as “hate” or “shame”, increased how widely it was shared by about 20%, and this spread happened mainly within liberal or conservative networks, not between them. A large pre-registered replication published in 2025 confirmed the effect, with a somewhat smaller estimate.
From the perspective of social identity theory, messages that express moral emotion about an issue also signal group membership, so they spread among people who share that identity and strengthen the boundary between groups. This can deepen group polarisation and hostility between political groups. Online settings therefore show both the processes that intensify conflict and a possible place to apply the theory’s remedies, such as highlighting shared identities.
Approach | Contribution to explaining intergroup behaviour | Implication for change |
|---|---|---|
Sociocultural | History, status differences, competition for resources and group norms define the relationship between groups. | Change the structure of contact: equal status, institutional support, cooperative goals. |
Cognitive | Categorisation, stereotypes and the salience of identities determine who counts as “us”. | Recategorise into a shared identity; contact provides information that challenges stereotypes. |
Biological | Threat produces emotional responses; brain activity differs for in-group and out-group members, but can change when group membership changes. | Reducing anxiety and threat in contact allows emotional ties to form. |
These levels interact. A shared threat, such as the earthquakes in the Vezzali study, is an environmental and emotional event that changed how children categorised each other. In Iraq, a recent history of violence left a level of threat and mistrust that one football season did not change outside the league. An explanation of intergroup behaviour that uses only one approach, for example treating prejudice as a personality trait or as a purely cognitive error, misses how history, cognition and emotion work together.
The strongest support for applying the theory comes from evidence that intergroup behaviour can be changed. Pettigrew and Tropp’s meta-analysis shows that contact reduces prejudice across hundreds of studies, and Mousa’s experiment shows that cooperative contact changes real behaviour. Both, however, show limits. Effects are moderate, change in feelings may come before change in beliefs, and change in one setting does not automatically spread to others. Lasting change between communities seems to need contact that is repeated, institutionally supported and connected to everyday life, not a single programme.
Much contact research is correlational: people with less prejudice may seek out contact, rather than contact reducing prejudice. Meta-analytic checks and experiments with random allocation, such as Mousa’s, address this concern. Explanations of real conflicts also involve many interacting causes, including economic competition, political leadership and history, so social identity processes are one cause among several rather than the whole explanation.
Prejudice is a construct that can be measured as feelings, beliefs, implicit associations or behaviour, and these do not always change together. Studies that measure only questionnaire attitudes risk social desirability bias; studies that measure only behaviour within an intervention may overstate its reach. The best evidence uses several measures and tests whether change generalises beyond the people and setting of the intervention.
Most research comes from Western countries and from majority-group participants. The experience of minority groups differs: for them, contact may bring exposure to discrimination, and recategorisation may feel like pressure to give up their identity. Research in post-conflict settings outside the West, such as Iraq, and attention to minority perspectives broaden the evidence and show that the effects of contact depend on power and history.
Applying the theory to real conflicts carries responsibility. Interventions can cause harm if poorly designed, for example by turning contact into competition. Presenting prejudice as a natural result of categorisation must not suggest that it is inevitable or excusable; the same research shows that categories are flexible and that bias can be reduced.
In this context, social identity theory can be applied in Paper 1 Section B to a scenario about group behaviour, often asking how it could explain the behaviour or how it could be used to change it. It can also be the area of study in a Section C essay, combined with any of the concepts; change and causality fit particularly well.
Social identity theory explains intergroup behaviour through categorisation, identification, comparison and the wish for a positive social identity.
Prejudice is an attitude and discrimination is behaviour; favouritism becomes hostility under threat, strong identification, illegitimate status differences and hostile group norms.
Dehumanisation, seeing out-group members as less than human, predicts support for violence against them.
Who counts as “us” decides who is helped: making a more inclusive identity salient extended helping to rival fans.
Realistic conflict theory explains conflict through competition for resources; at Robbers Cave, competition produced hostility and superordinate goals reduced it, while favouritism began before competition.
Contact reduces prejudice across 515 studies, especially under equal status, common goals, cooperation and institutional support.
Recategorisation into a common in-group, ideally with a dual identity, reduces bias by moving the group boundary.
Mousa (2020) showed that cooperative contact in football teams changed Christian players’ behaviour towards Muslim peers in post-ISIS Iraq, but the change did not spread to other settings.
Attempts to change intergroup behaviour are evaluated through the extent and durability of change, causality, measurement of attitudes and behaviour, bias and responsibility.
I can explain how social identity theory accounts for intergroup conflict, prejudice, discrimination and helping.
I can explain prejudice, discrimination and dehumanisation and when favouritism becomes hostility.
I can compare and contrast social identity theory and realistic conflict theory using the Robbers Cave study.
I can explain how contact, superordinate goals and recategorisation can change group behaviour.
I can describe and evaluate Mousa’s (2020) field experiment.
I can discuss how biological, cognitive and sociocultural factors interact in intergroup behaviour.
I can evaluate interventions with reference to change, causality, measurement and responsibility.