Researchers presented participants with just one or two examples of information that strongly challenged their pre-existing stereotypes. these researchers found that, when presented with just one or two examples that challenge a strongly held stereotype, people

These specialists found that, when given only maybe a couple cases that test a firmly held stereotype, individuals rejected the new data and reinforced their stereotypic convictions. 
A stereotype is a suspected that can be embraced about particular sorts of people or certain methods for getting things done. These musings or convictions might precisely reflect reality.