#dilution effect

Saving Wildlife is Good for Your Health (But It's Complicated)

Although we do use stereotypes when evaluating individuals about whom we know nothing else, the effects of stereotypes can be reduced or eliminated when we are given some additional information about these individuals, even if we view this information as completely irrelevant to the judgment at hand. (. . .) Nisbett and his colleagues, who named this phenomenon the dilution effect, showed that nondiagnostic information can also dilute the impact of other kinds of diagnostic information (Nisbett, Zukier, & Lemley 1981). For example, people given information that they consider indicative of whether a social-work client is likely to be a child abuser (e.g., "He is aroused by sadomasochistic sexual fantasies," "He has a drinking problem") viewed this person as quite likely to be a child abuser. But other people, who were given, in addition to this diagnostic information, some completely irrelevant information about the person (e.g., " He manages a hardware store," "He has an IQ of 110") viewed him as less likely to be a child-abuser. In other words, the nondiagnostic information diluted the impact of the diagnostic information on judgment.