Research was conducted to understand and extend Rothbart and Park's (1986) innovative study of trait attribution. Participants estimated the baserate frequency of correspondent behaviors and the behavioral expectations of trait stereotypes. The frequency of correspondent behavior appears to determine the evidence needed to confirm and disconfirm traits observed by Rothbart and Park by shaping the behavior expected of persons with a trait. When the baserate of correspondent behavior is high, it is generally expected of everyone, and less likely to impact trait attributions. In contrast, when correspondent behavior is uncommon, it is expected primarily of persons with a trait, and weighted more heavily in the inference process. The findings help to explain why traits that are "hard to acquire are easy to lose" and why positive trait attributions are harder to acquire but easier to lose than negative trait attributions.