Perceived beauty is one of the strongest predictors of perceived cooperativeness, causing the “beauty bias”. Through a large three-stage incentivized behavioral and rating experiment (N=357), we study (1) the beauty bias in incentivized predictions of cooperativeness and (2) the ex-post relevance of beauty ratings for predicting cooperativeness in an incentivized game. We additionally (3) investigate if one's beauty influences the beauty bias in predictions of cooperativeness of others. Our findings demonstrate the robustness of the beauty bias and its irrelevance for making accurate predictions. We further observe that individuals are affected by the beauty bias irrespective of their beauty. Overall, the results highlight the importance of strong institutions that protect individuals from falling prey to the beauty bias.