The Act Frequency Approach (AFA) proposed by Buss and Craik was summarized and critically reviewed on the basis of a German replication study using six interpersonal traits each with 100 translated acts. The six traits studied were dominant, gregarious, agreeable, submissive, aloof, and quarrelsome. The internal structure of these categories was examined via multiple prototypicality ratings. It was demonstrated that many acts are highly prototypical for more than one category. The manifested categorical structure was tested by gathering retrospective act reports about performance and frequency of exhibiting each of these 600 acts using a sample of 213 adults. Aggregation of the acts according to their prototypicality key yielded reliable subscales. The validities obtained on the basis of the 25 highly prototypical acts were slightly higher compared with those of the 100 act set, as well as the sets with lower prototypicality. The validity gradient proposed by Buss and Craik was found using selected personality scales as well as global self-ratings and peer-ratings on some of the respective trait terms. In general, the results of the German study replicated the findings of Buss and Craik.