Key Studies of Prejudice and Discrimination

Introduction: Why do people judge others? 🌍

students, prejudice and discrimination are important ideas in psychology because they help explain why people sometimes treat others unfairly based on group membership such as race, gender, nationality, religion, or social class. In everyday life, these ideas appear in schools, workplaces, sports, online spaces, and even friendships. Understanding them matters because prejudice can shape relationships, social identity, conflict, and cooperation.

In this lesson, you will learn the main ideas and terminology linked to key studies of prejudice and discrimination in IB Psychology SL. You will also see how psychologists investigate these ideas using experiments, observations, and real-world examples. By the end, you should be able to explain major studies, use correct vocabulary, and connect the topic to Psychology of Human Relationships.

Learning goals

• Explain the main ideas and terminology behind key studies of prejudice and discrimination.
• Apply IB Psychology SL reasoning to the methods and findings of these studies.
• Connect prejudice and discrimination to social identity, group behaviour, and relationship change.
• Use evidence from key studies to support psychological explanations.

Prejudice is usually a negative attitude toward a group, while discrimination is unfair behaviour directed at people because of group membership. A person can have prejudice without always acting on it, but discrimination involves action. Stereotypes are beliefs about a group, such as “all members of this group are like this,” and these can fuel both prejudice and discrimination.

Core concepts: What psychologists mean by prejudice and discrimination

To study prejudice properly, psychologists need clear definitions. One useful way to think about it is through three related parts of attitude: thoughts, feelings, and behaviour.

A stereotype is the cognitive part, or what a person believes about a group. For example, someone might incorrectly believe that a certain nationality is “bad at teamwork.” A prejudice is the emotional or evaluative part, such as feeling dislike, fear, or suspicion toward that group. Discrimination is the behavioural part, such as refusing to hire someone because of their ethnicity.

These ideas are strongly connected to social identity theory. Social identity theory says people form part of their identity from the groups they belong to. This can lead to in-group bias, where people prefer their own group, and out-group discrimination, where they judge outsiders more harshly. students, this is one reason prejudice is not only about individual personality; it can also be a group process.

A second important idea is realism versus social construction. Some studies show that prejudice can be created or intensified by competition for resources, while others show it can be shaped by culture, language, and norms. This helps psychologists explain why prejudice changes across situations rather than being fixed.

Key Study 1: Sherif’s Robbers Cave experiment 🏕️

One of the most famous studies linked to prejudice and discrimination is Muzafer Sherif’s Robbers Cave experiment. This study looked at how group conflict develops. Sherif brought boys to a summer camp and divided them into two groups. At first, each group became bonded through shared activities. Later, the groups competed in games for prizes. Soon, hostility developed, and the boys began insulting, sabotaging, and discriminating against the other group.

The main idea was realistic conflict theory. This theory says prejudice and discrimination increase when groups compete for limited resources. The conflict does not need to come from deep personal hatred at the start; it can grow because each group sees the other as a rival.

Sherif later tried to reduce the conflict by creating superordinate goals, which are goals that both groups can achieve only by working together. When the boys had to cooperate, hostility decreased. This finding is very important for relationship change because it suggests prejudice can be reduced through shared goals and interdependence.

Why this study matters

Sherif’s study shows that prejudice is not only about personality or ignorance. Social situations matter. When groups compete, they may become more hostile; when they cooperate for a shared aim, relations can improve. This is highly relevant to schools, sports teams, and community groups where competition may sometimes increase tension.

Key Study 2: Tajfel’s minimal group studies 🧪

Henri Tajfel wanted to know whether people would still show bias even when group differences were meaningless. In minimal group studies, participants were randomly assigned to groups based on trivial criteria, such as preferences for abstract paintings or coins tossed in a coin flip. There was no real history, no real rivalry, and no personal interaction.

Even in these minimal groups, participants often showed in-group bias when making allocation decisions. They tended to give more rewards to members of their own group, even if it meant their group did not receive the maximum total reward. This showed that people do not need strong reasons to favour their own group; simply being labelled as part of a group can be enough.

Tajfel’s findings support social identity theory. People want a positive social identity, so they may compare their group favourably with others. This can create discrimination even when the groups are artificial.

Example in real life

Imagine students is randomly placed into Team A in a class activity. Even if Team A and Team B were created seconds ago, members might still start rooting for their own team more strongly. That small “us versus them” feeling is the kind of process Tajfel helped reveal.

Key Study 3: Pettigrew and Tropp on intergroup contact 🤝

A major question in prejudice research is how to reduce discrimination. One of the most influential pieces of evidence comes from the intergroup contact hypothesis, strongly supported by Pettigrew and Tropp’s meta-analysis. A meta-analysis combines results from many studies to look for overall patterns.

Their research found that, in general, contact between groups is associated with lower prejudice. The effect is stronger when certain conditions are present, including equal status between groups, cooperation, common goals, and support from authorities or social norms. These conditions help make contact positive rather than tense.

This is important because it shows that prejudice can change. It is not permanent. When people interact under fair and supportive conditions, they are more likely to reduce stereotypes and build empathy.

Real-world application

Schools often use mixed group projects, peer mentoring, and collaborative tasks to reduce bias. These work best when students feel equal, have to cooperate, and are supported by teachers. Without those conditions, contact may not improve relationships and may even increase conflict.

Key Study 4: Bandura and the role of modelling 🎭

Although Bandura is best known for social learning theory, his work also helps explain prejudice and discrimination. People learn behaviour by observing models. If children see adults or peers using insulting language, excluding others, or acting unfairly, they may copy those behaviours.

This is important because prejudice can be transmitted socially. A child may not invent a stereotype independently; instead, they may learn it from family, media, or peer groups. Over time, repeated exposure can make discriminatory behaviour seem normal.

This idea helps explain why prejudice can persist across generations. It also connects to relationship change because new norms and positive models can encourage more respectful behaviour.

Evaluating the studies: What IB wants you to notice 📚

IB Psychology asks students to do more than memorize findings. You need to evaluate how evidence is gathered and what it means.

One strength of Sherif’s study is that it had strong ecological validity because the boys behaved in a realistic camp setting. However, a limitation is that the sample was small and not diverse, so generalizing the results to all groups should be done carefully.

Tajfel’s studies were highly controlled, which is a strength because it allowed him to isolate the effect of group categorization. However, the task was artificial, so critics question how closely the findings reflect real-life discrimination.

Pettigrew and Tropp’s meta-analysis is powerful because it combines many studies and gives a broad conclusion. A limitation is that meta-analyses depend on the quality of the studies included. If some studies have weak methods, they can affect the overall result.

When evaluating, students, always think about validity, reliability, ethics, and application. Ethical issues matter because research on prejudice can involve deception, stress, or negative group feelings. Psychologists must protect participants while still studying real attitudes and behaviour.

How these studies fit the wider topic of Human Relationships ❤️

Prejudice and discrimination are part of human relationships because they influence how people form, maintain, and end social bonds. They affect friendships, romantic relationships, workplace teamwork, and community trust. They also connect to communication, because biased language can create distance and misunderstanding.

These studies also link to group dynamics and conflict. Sherif shows how competition can create hostility, while Tajfel shows how simple group labels can produce bias. Pettigrew and Tropp show how contact can reduce tension. Together, these studies show that relationships are shaped by both group membership and social context.

They also relate to prosocial behaviour and social responsibility. If people understand how prejudice forms, they may be more likely to challenge unfairness, support inclusion, and act as bystanders who intervene when discrimination happens.

Conclusion: What should students remember?

Key studies of prejudice and discrimination show that bias is not just an individual flaw. It can emerge from competition, group identity, learned behaviour, and social context. Sherif showed how conflict grows and how cooperation reduces tension. Tajfel showed that even minimal group labels can create in-group bias. Pettigrew and Tropp showed that well-designed contact can lower prejudice. Bandura helps explain how biased behaviour is learned and repeated.

For IB Psychology SL, the main goal is to connect evidence to theory. students, if you can explain what prejudice and discrimination are, describe the studies accurately, and evaluate their strengths and limitations, you are demonstrating strong understanding of Psychology of Human Relationships.

Study Notes

• Prejudice is a negative attitude toward a group.
• Discrimination is unfair behaviour toward people because of group membership.
• Stereotypes are beliefs about a group and can lead to prejudice.
• Social identity theory explains in-group bias and out-group discrimination.
• Sherif’s Robbers Cave study supported realistic conflict theory.
• Superordinate goals can reduce conflict by making groups cooperate.
• Tajfel’s minimal group studies showed that even trivial group labels can produce bias.
• Pettigrew and Tropp found that intergroup contact usually reduces prejudice.
• Contact works best with equal status, cooperation, shared goals, and support.
• Bandura’s social learning theory helps explain how prejudice can be learned from models.
• Evaluation should include validity, reliability, ethics, and real-world application.
• These studies connect directly to relationships, group dynamics, and social responsibility.