Rewards have a profound impact on human motivation, cognition, affect and behavior. The study of reward processing and the effects of incentives thus occupies a central place in psychology and cognitive neuroscience. A core assumption when comparing groups or individuals is that reward types are valued equally. Here we test the validity of this assumption in a sample of 26 adults 23children (7-11 years) using both primary (i.e. pleasant taste) and secondary rewards (i.e. money). We show that

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... lts value money more than pleasant tastes, while children value them equally, a developmental pattern replicated across three distinct tasks including subjective valuation, willingness to exert cognitive effort, and the invigorating effects on cognitive control. Our findings suggest that money increases in value with age, presumably with experience, and warrant caution when interpreting group differences in reward processing, at least in a developmental framework. Future work should expand to using incentives that are appropriate to the groups under investigation.