Although economic risk proneness is usually observed in young children, the issues of how this preference changes during development and how novelty and uncertainty interact in motivating children's economic choices are unclear. This study investigated the developmental trajectory and mechanisms underlying attitude toward risk in the gain domain between 7 and 9 years of age. A total of 225 7- to 9-year-olds were presented with a series of gambling tasks in which they needed to choose between two options: one safe and one risky but with the same expected value. Among the three tasks proposed to participants, an unexpected event was associated with the risky option in one task and with the safe option in another task. By revealing that children become less attracted to uncertainty in gain contexts from 7 to 9 years of age, our results indicate a decrease in economic risk proneness at the onset of middle childhood. Our findings also showed that 7- to 9-year-olds choose the novel option more often when it is associated with risk versus safety. We suggest that economic risk proneness in young children is driven more by uncertainty exploration than by novelty-seeking.