Individuals differ in their perceptions of actprototypicality. This study examined whether incorporating such individual differences enhances trait-behaviour correlations and provides stronger evidence for cross-situational consistency. Three hundred and fifty-three subjects rated the dominance prototypicality of 100 acts, indicated how often they performed each of these acts, and provided trait ratings of how dominant they were in general. There were substantial and reliable individual differences in prototypicality judgements over a 4–5 month period. A variety of weighting schemes were used to incorporate these individual differences, but none dramatically increased the trait-behaviour correlation. Similarly, incorporating individual differences did not increase the magnitude of cross-situational consistency correlations. However, incorporating individual differences did enhance the pattern of trait-behaviour and consistency correlations from less prototypical to highly prototypical acts. Differences in perceptions of act prototypicality thus do not affect the magnitude of the correlations that can be obtained, but they are useful in revealing theoretically meaningful patterns of relationships.