Key Studies of Prejudice and Discrimination

Welcome, students 🌍 In this lesson, you will explore some of the most important studies in the psychology of prejudice and discrimination. These studies help explain why people form negative attitudes toward others, how stereotypes can affect behaviour, and what happens when groups are treated unfairly. By the end of this lesson, you should be able to explain the main ideas, use key terminology correctly, and connect the research to real-world relationships and social life.

Introduction: Why study prejudice and discrimination?

Prejudice is an attitude, often negative, toward a person because they belong to a particular group. Discrimination is behaviour that treats people unfairly because of group membership. These ideas matter in friendships, workplaces, schools, sports teams, and online communities. For example, if a student assumes someone is “bad at maths” because of their gender or background, that is prejudice. If that student is then left out of a group project because of that assumption, that is discrimination.

In IB Psychology HL, the study of prejudice and discrimination fits within Psychology of Human Relationships because these processes shape how people interact in groups, how conflict grows, and how relationships can be damaged or repaired. The key studies in this area show that prejudice is not only about personal dislike. It can also be influenced by social norms, group competition, identity, and obedience to authority.

Learning goals

By studying the key research, students, you will be able to:

explain major terms such as prejudice, discrimination, stereotype, social identity, and outgroup;
describe important studies accurately;
apply the findings to real-life examples;
connect the research to broader themes in relationships, group dynamics, and conflict.

Sherif and the Robbers Cave Study: group competition and conflict

One of the most famous studies linked to prejudice is Sherif’s Robbers Cave experiment. Sherif and colleagues studied two groups of boys at a summer camp. The boys were split into separate groups and first developed strong ingroup bonds. Then the groups competed in games for prizes. This competition quickly created hostility, name-calling, and discrimination between the groups.

Sherif’s work showed that prejudice can grow when groups compete for limited resources. This is called realistic conflict theory. The theory says that when groups believe they want the same reward, power, or status, conflict becomes more likely. The boys did not start out as enemies. The situation changed their behaviour. That is an important point in psychology: prejudice can be shaped by context, not just personality.

A useful example is school sports. If two teams constantly fight over the best equipment, the most attention, or the top ranking, they may begin to see each other as rivals first and people second. Over time, insults and stereotypes may follow 🏆

Sherif also found that conflict could be reduced by superordinate goals, which are goals both groups must work together to achieve. When the boys had to cooperate to solve shared problems, hostility decreased. This matters for human relationships because it suggests that cooperation can reduce prejudice more effectively than simply telling people to “be nicer.”

Tajfel and Social Identity Theory: categorizing people into groups

Henri Tajfel’s research helped explain why prejudice can happen even without direct competition. His work on minimal groups showed that people can favour their own group even when group membership is based on something trivial, like tossing a coin or choosing a painting style. This is called ingroup bias.

Tajfel developed social identity theory, which says that part of a person’s self-esteem comes from the groups they belong to. People want their ingroups to feel positive and successful. This can lead them to compare their group with an outgroup and see their own group as better. Prejudice may grow because making the ingroup seem superior helps protect self-image.

Important terms here include:

Ingroup: the group a person belongs to.
Outgroup: a group a person does not belong to.
Ingroup bias: favouring one’s own group.
Social identity: the part of the self-concept based on group membership.

A real-world example could be fans of rival music genres, schools, or online communities. Even if the differences are small, people may still defend their group and make unfair judgments about outsiders. This helps explain why prejudice can appear quickly and sometimes with very little real reason.

Tajfel’s findings are important in IB because they show that discrimination can come from ordinary group processes. students, this means prejudice is not always caused by extreme hatred. Sometimes it begins with simple categorization and a desire to belong.

The role of stereotypes in prejudice

A stereotype is a fixed, oversimplified idea about a group. Stereotypes can be positive, negative, or mixed, but they are still dangerous because they ignore individual differences. Prejudice often develops when stereotypes become emotionally loaded beliefs about what group members are like.

Psychologists have shown that stereotypes can affect memory, judgment, and behaviour. For example, if someone believes a group is aggressive, they may interpret neutral behaviour as threatening. This can create a self-fulfilling cycle: the stereotype leads to unfair treatment, and the unfair treatment produces conflict that seems to “prove” the stereotype.

In everyday life, stereotypes appear in jokes, media, classroom expectations, and social media posts. A student may be praised for speaking well because others did not expect much from their group, or may be ignored because people assume they will not contribute. These small acts can accumulate into discrimination.

A key psychological idea is that stereotypes reduce complexity. Human beings like quick mental shortcuts, especially when meeting new people. However, shortcuts can lead to bias. That is why understanding stereotypes is essential for understanding prejudice.

Social categorization and “us versus them” thinking

Another important concept is social categorization. People naturally sort others into groups based on visible features such as age, clothing, language, ethnicity, nationality, or role. Categorization helps the brain process social information quickly, but it can also encourage exaggeration of differences between groups.

Once people categorize others, they may begin using “us” and “them” language. This can make relationships more tense because outsiders are seen as less trustworthy or less deserving of respect. The more a group is seen as different, the easier it becomes to justify discrimination.

This process can be seen in conflicts between friend groups, political groups, or nations. For example, during a heated online debate, people may stop seeing the other side as individuals and instead treat them as a single hostile group. In psychology, this is important because prejudice is often maintained by social perception, not only by personal experiences.

Key studies, evidence, and what they tell us

The main value of these studies is that they show prejudice is learned, maintained, and changed through social processes. Sherif’s study highlights competition and cooperation. Tajfel’s research highlights identity and group bias. Together, they show that prejudice is not one single thing. It can come from resource conflict, group membership, stereotypes, and the need to feel good about one’s group.

For IB Psychology HL, it is important to use evidence properly. When writing or speaking about these studies, students, you should:

state the aim clearly;
describe the procedure in a simple but accurate way;
explain the findings;
connect the findings to prejudice and discrimination;
evaluate how well the study explains real-world behaviour.

For example, Sherif’s study has strong ecological validity because it took place in a realistic summer camp setting. However, it used only boys, so the findings may not apply equally to all people. Tajfel’s minimal group research is powerful because it shows how quickly bias can appear, but the situation is artificial, so it may not fully represent real-life prejudice. These evaluation points are useful in essays and short-answer responses.

Applying the studies to human relationships and social responsibility

Prejudice and discrimination affect relationships at many levels. In families, children may learn attitudes from parents. In schools, prejudice can isolate students and harm group trust. In workplaces, it can influence hiring, promotion, and teamwork. In communities, it can increase conflict and reduce social cohesion.

These studies also link to social responsibility, which is the idea that people and groups should act to reduce harm and support fairness. If prejudice is partly caused by group processes, then solutions should also be social. Examples include cooperative learning, shared goals, inclusive rules, contact between groups under fair conditions, and challenging stereotypes in media and education.

A useful classroom example is group work. If students are divided in a way that encourages competition, prejudice may increase. If students from different backgrounds must work together toward a common goal, respect may improve. This fits the message from Sherif: cooperation can reduce hostility.

It is also important to remember that not all differences between groups are equal. Power matters. Prejudice often affects groups that already have less social status or fewer opportunities. That is why discrimination is not just about feelings; it has real consequences for identity, access, and well-being.

Conclusion

The key studies of prejudice and discrimination show that unfair attitudes and actions are shaped by social situations, group identity, and competition. Sherif demonstrated that conflict can grow when groups compete, but cooperation can reduce hostility. Tajfel showed that people can favour their own group even in very simple settings, proving how easily ingroup bias can appear. Together, these studies explain why prejudice is such a powerful force in human relationships.

For IB Psychology HL, the most important takeaway is that prejudice is not fixed. It can be created by social conditions and reduced by changing those conditions. Understanding this helps students explain not only the science, but also the real-world importance of fairness, empathy, and cooperation 🤝

Study Notes

Prejudice is an attitude; discrimination is behaviour.
A stereotype is a simplified belief about a group.
Sherif’s Robbers Cave study showed that competition between groups can increase hostility and discrimination.
Realistic conflict theory explains prejudice as the result of competition over limited resources.
Superordinate goals can reduce conflict because groups must cooperate.
Tajfel’s minimal group studies showed that even trivial group divisions can produce ingroup bias.
Social identity theory says that group membership contributes to self-esteem and can encourage “us versus them” thinking.
Ingroup = group you belong to; outgroup = group you do not belong to.
Prejudice can be shaped by social categorization, stereotypes, identity, and group competition.
These studies connect to human relationships because they explain conflict, exclusion, cooperation, and social responsibility.
IB answers should include accurate study details, key terms, findings, and evaluation.
The big message: prejudice is learned and socially influenced, so it can also be reduced through social change.