Prejudice refers to prejudging someone or forming an opinion about them before knowing the relevant facts, usually in a negative way based on their group memberships. Stereotypes simplify our social world by reducing people to overgeneralized ideas about their group but can lead to prejudice when we assume certain characteristics of individuals based on their perceived group. Common types of prejudice include those based on gender, ethnicity/race, class, age, sexual orientation, disability, and more. It is important to be aware of our own prejudices and stereotypical thinking in order to prevent discrimination.