Selective perception is a form of bias that causes people to perceive messages and actions according to their frame of reference. Using selective perception, people tend to overlook or forget information that contradicts their beliefs or expectations.
There are two types of selective perception. Perceptual vigilance refers to people noticing stimuli such as advertising or news reports that are significant to them. For example, someone considering buying a certain brand of car is more likely to notice ads about that car than someone who is neutral to the brand. In contrast, perceptual defense refers to people creating a barrier to screen out stimuli they find threatening or unpleasant. For example, a smoker might filter out a photo of a diseased lung.
A classic study that illustrates both types of selective perception. When students at Princeton and Dartmouth universities watched a film of a football game between the two schools, the Princeton students noticed more penalties committed by Dartmouth, and the Dartmouth students noticed more penalties committed by Princeton. Each group judged the football game depending on their team allegiance and ignored evidence that contradicted what they wanted to see.
Experts say that the factors influencing selective perception include previous experiences, attitudes, conditioning, gender, age, race and emotional state.