This document is a chapter from a PowerPoint presentation on prejudice that outlines its causes. The chapter discusses how prejudice is an ubiquitous social phenomenon that affects everyone. It examines how our thinking processes like categorization and schemas can lead to prejudice through in-group bias and out-group homogeneity. Attributional biases like the fundamental attribution error and self-fulfilling prophecies also contribute to prejudice. Prejudice can arise from economic competition over limited resources. Conforming to social and cultural norms that promote stereotypes through institutionalized racism and sexism also causes prejudice.