The base-rate fallacy states that the use of stereotypes is eroded when subjects are given minimal but diagnostic, individuating information about a target. To examine the effect of causal attributions and subject gender on the use of stereotypes in evaluations and predictions, 180 college students (90 males, 90 females) were presented with one of three vignettes of a person behaving assertively. One version gave no attributional information while the others included a causal attribution which was internal and stable (IS) or external and unstable (EU). The gender of the actor in the descriptions was systematically varied. Subjects evaluated the actor's assertiveness, predicted the likelihood of future assertiveness, and estimated the percentage of males and females who were assertive. An analysis of the results showed that subjects did hold the stereotype that men are more assertive than women, with female subjects believing the gender gap to be larger. The IS attribution condition produced significantly higher evaluation and prediction ratings than the EU attribution condition. The use of the stereotypes was eroded for evaluation, but when predicting future assertiveness, male subjects used the stereotype while female subjects did not. Future research should identity under what circumstances and in what settings gender will elicit differential attributions. (BL)