Stereotypes occur when someone judges or characterises a group of people based on insufficient information. Stereotypes may be based on a person's experiences with only a few members of the stereotyped group, on wishful thinking or on incorrect information. People within the stereotyped group are deprived of their individuality and expected to share similar traits based solely on their membership in the group.
People who indulge in stereotyping tend to pursue situations and information that reinforce their beliefs. This has the effect of sealing the person off from experiences and interactions that might challenge his stereotypes, thus maintaining his narrow mindedness. Living for long periods of time in such a tightly self-controlled environment, a person's mind runs the risk of becoming ever more narrow, never opening up to the wide diversity of possibilities that are offered by other people.
Loss of Opportunities
A person who interacts with other people on an individual basis makes herself available to a wide range of opportunities. By accepting people on their own terms and recognising that each person is different, she helps her own social, psychological and professional situation as well as those of others. People who stereotype groups of other people cut themselves off from these opportunities by making unfounded assumptions based on another person's race, colour, gender or culture. Opportunities can appear in unexpected times and places, offered by unexpected people, and those who are open to them will benefit far more than those who move through life with a rigid and often badly flawed view of reality.
In some situations, stereotyping may move beyond the limiting of a person's experience and result in legal consequences. An employer who denies a job to a person of a certain race because of assumptions he holds about people of that race may be hit with a discrimination lawsuit. Judging someone's abilities by his race is illegal, because society has determined that stereotypes are not only unfounded but harmful to the people to whom they are applied. People in professional positions who are prone to stereotyping others can advance their own careers by overcoming this outmoded manner of thinking.
A person who stereotypes others tends to isolate herself from the groups that she stereotypes, but she may find herself isolated by other people who are not in those groups. In progressive and professional environments, people who are perceived as racists and bigots tend not to be very popular, and others will tend to avoid them both because they don't like their opinions and because they don't want to be seen by others as sharing those opinions. This isolation serves as a very clear social signal to most people that intolerant thinking is not acceptable among many other people.