When people voluntarily take on unpleasant tasks such as housework, they tend to be in particularly happy states, according to a new study on hedonism. The finding challenges an old prediction by some researchers that humans can be constant pleasure-seekers. Instead, the new study suggests we might seek out fun, uplifting activities mainly when we’re in bad or down moods. But when we’re on the up, we’re more likely to go for the dull and dreary assignments.

This finding of “flexible hedonism,” reported Monday in The Proceedings of the National Academy of Sciences, may seem counterintuitive because it suggests we sabotage our own high spirits. But it hints at the idea that humans tend to make sensible short-term trade-offs on happiness for long-term gains.