The present study investigates the effects of evaluative processing of hostile and friendly words on impression formation. Two experiments were conducted. Subjects were first asked to complete sentences using hostile (Experiment 1) or friendly (Experiment 2) words. Then they participated in an ostensibly unrelated impression task, where they rated a stimulus person on a series of trait scales based on a paragraph of behavioural descriptions that was ambiguous regarding hostility (Experiment 1) or friendliness (Experiment 2). It was found that the hostile sentence completion tasks increased the likelihood that subsequent behavioural information would be assimilated into the primed hostile constructs, whereas the friendly sentence completion tasks increased the likelihood that behavioural information would be contrasted to the primed friendly constructs. The underlying mechanism of the positive-negative asymmetry of priming effects was discussed in terms of the socio-cultural expectancy for normality of friendliness being evoked by priming manipulations. In addition, a supplementary experiment was conducted to assess the feeling states following the hostile or friendly priming tasks. It was found that the hostile priming elicited negative affects, whereas friendly priming had no effects on the feeling states of subjects. This asymmetric effect of priming on the feeling states was also considered as a result of the influences of the socio-cultural expectancy.