People who are prejudiced feel a much stronger need to make quick and firm judgments and decisions in order to reduce ambiguity. "Of course, everyone has to make decisions, but some people really hate uncertainty and therefore quickly rely on the most obvious information, often the first information they come across, to reduce it" Roets says. That's also why they favor authorities and social norms which make it easier to make decisions. Then, once they've made up their mind, they stick to it. "If you provide information that contradicts their decision, they just ignore it."
Roets argues that this way of thinking is linked to people's need to categorize the world, often unconsciously. "When we meet someone, we immediately see that person as being male or female, young or old, black or white, without really being aware of this categorization," he says. "Social categories are useful to reduce complexity, but the problem is that we also assign some properties to these categories. This can lead to prejudice and stereotyping."
People who need to make quick judgments will judge a new person based on what they already believe about their category. "The easiest and fastest way to judge is to say, for example, ok, this person is a black man. If you just use your ideas about what black men are generally like, that's an easy way to have an opinion of that person," Roets says. "You say, 'he's part of this group, so he's probably like this.'"