Curiosity is pervasive in our everyday lives, but little is known about its underlying mechanisms. In the current study, we assessed whether curiosity about uncertain outcomes is modulated by the valence of the information, i.e. whether the information is good or bad news. Using a lottery task in which outcome uncertainty, expected value and outcome valence (gain versus loss) were manipulated independently, we found that curiosity is overall higher for gains compared with losses. Surprisingly, curiosity increased with increasing outcome uncertainty for both gains and losses, contradicting models that posit that humans seek positive and avoid negative information. Curiosity thus follows from multiple drives, including a drive to improve our world model, as well as, separately, a drive to maximize positive information.