We provide causal evidence that optimistic beliefs regarding the role of hard work in success, while leading to success, diminish the individual’s sympathy toward the unsuccessful. We generate random variation in beliefs via an educational intervention, which imparts to elementary school children the idea that ability, rather than being innately fixed, can be developed through effort. To evaluate the impact of the intervention we create an experimental setting where both control and treatment students are given the opportunity to accumulate ability in a real effort task and earn rewards upon success. Against this background, we implement an altruism experiment where we manipulate the donation context in terms of the potential reasons for the anonymous recipient’s poorness. We find that while treated students are no less likely than control to give to recipients who are poor because of bad luck, they are significantly less likely to give to those who failed at the task. The more optimistic the beliefs, the less altruistic the children become toward the unsuccessful. The results reveal important interactions between education and development of social and redistributive preferences.