Public service stereotypes have been the subject of various studies in public administration research. However, the cognitive processes that form the basis of these stereotypes and the heuristics processing of stereotypical information, remain empirically vague. Starting from insights on the anti-public sector bias and representativeness heuristic, we apply an experimental vignette study (n = 1,412) in which we analyze how citizens process information on employees' sector affiliation. Furthermore, we integrate non-work role-referencing to test the stereotype confirmation assumption underlying the representativeness heuristic. Our results show that sector as well as non-work role-referencing influences perceived employee professionalism but has little effect on positive stereotype confirmation. However, our results do not confirm a congruity effect of consistent stereotypical information.