The racial tension and profiling allegations behind the Zimmerman trial have thrown stereotyping into sharp relief. While stereotypes are socially problematic, they also have an evolutionary function. While they are often false, they usually have their origin in some truth. While they form as part of our basic psychological processes, they can be cognitively altered.
By definition, a stereotype is a “fixed, over generalized belief about a particular group or class of people.” They form as part of our brain’s tendency to categorize like things. When group X usually has trait Y, we assume that a random person from group X will have trait Y. This allows humans to respond rapidly to situations based on similar (but not identical) past experiences.
This can become problematic because stereotypes are very slow to change. When we see an exception to the stereotype, our initial reaction is to see the individual as atypical. There is also a tendency to ignore evidence disproving the stereotype, and focus on evidence that confirms existing beliefs. Research has shown that when people are primed with knowledge that an individual belongs to a certain group, they are faster at categorizing terms that fit within the primed category.
The core issue of stereotyping is the purpose of making rapid judgments. When time pressures were imposed on subjects increased the use of ethnic stereotyping in judgments. Conversely, when tasks were more complicated, automatic stereotype activation was uncommon. So our stereotyping functions on both a conscious and unconscious level. The more we examine the nuance of a situation, the less likely we are to rely on a stereotype. The more information we consider, the more we examine the continuum that objects exist on.
U.S. Census, People Quick Facts: http://quickfacts.census.gov/qfd/states/00000.html
Simply Psychology, Stereotypes: http://www.simplypsychology.org/katz-braly.html
MIT, The Cognitive Roots of Stereotyping: http://adam.oliner.net/comp/stereotyping.html