("women are warm") or negative ("teenagers are lazy"). Stereotypes can lead to imperfect beliefs, but they can also result in both prejudice and discrimination.

　　According to psychologist Gordon Allport, prejudice and stereotypes appear in part as a result of normal human thinking. In order to make sense of the world around us, it is important to sort information into mental categories.

　　"The human mind must think with the aid of categories," Allport explained.

　　"Once formed, categories are the basis for normal prejudgment. We cannot possibly avoid this process. Orderly living depends upon it."

　　This process of categorization applies to the social world as well, as we sort people into mental groups based on factors such as age, sex and race.

　　However, researchers have found that when it comes to categorizing information about people, we tend to minimize the differences between people within groups and exaggerate (夸大） the differences between groups. In one classic experiment, participants were asked to judge the height of people shown in photographs. They were told that:

　　"In this booklet, the men and women are actually of equal height. We have taken care to match the heights of the men and women pictured. That is, for every woman of a particular height, somewhere in the booklet there is also a man of that same height. Therefore, in order to make as accurate a height judgment as possible, try to judge each photograph as an individual case; do not rely on the person's sex."

　　Despite this, because of their prejudgment that men are taller than women, the participants were unable to dismiss their existing categorical beliefs about men and women in order to judge the heights accurately.

In addition to looking at the reasons why prejudice occurs, researchers have also explored different ways that prejudice can be reduced. Training people to become more empathetic (善解人意的） to members of other groups is one method that has shown considerable success. By imaging themselves in the same position, people are able to think about how they would react and gain a greater understanding of other people's actions.

Other techniques that are used to reduce prejudice include:

　　• Passing laws and regulations that require fair and equal treatment for all groups of people.

　　•Increased contact with members of other social groups.

　　•Making people aware of the conflicts in their own beliefs.

　　How Prejudice Forms and How to Prevent It

What does the word prejudice(1) to us? •Prejudice is an opinion that often goes (2) the fact, with no valid basis.

•Prejudice tends to cause unfair treatment called discrimination.

•A judgment about a person or group is reached (3) the evidence is available.