Recent reasoning accounts suggest that people can process elementary logical principles intuitively. These controversial “logical intuitions” are believed to result from a learning process in which developing reasoners automatize their application. To verify this automatization hypothesis, we contrasted the reasoning performance of younger (7th grade) and older (12th grade) reasoners with a two-response paradigm. Participants initially responded with the first intuitive response that came to mind and subsequently were allowed to deliberate on classic “bias” problems (base-rate problems and syllogisms). Results (...) showed that in addition to showing less deliberate correction of an initial erroneous response, younger reasoners were specifically less likely to generate the correct response from the outset. The findings lend credence to the role of a developmental automatization process and indicate that developmental improvements in reasoning accuracy are at least partially driven by an improvement in the accuracy of our intuitions. (shrink)