I experimentally investigate the relation of endowment origin, cognitive abilities (as measured by the Cognitive Reflection Test, CRT), and co-operation in a one-shot linear public goods game. The results show that subjects’ contributions depend on an interplay of cognitive abilities and endowment origin. A house money effect exists only for subjects with low CRT scores. They contribute more when income was allocated to them and less when income was obtained by effort. In contrast, subjects with high CRT scores contribute the same amount independent of income type. The findings have implications for redistribution, team production, and experimental designs.