We study the role of the type of incentives and interactions children are exposed to in the learning environment, in the formation of competitive preferences and gender differences therein. Specifically, we design and evaluate the effects of two educational interventions based on teaching elementary school students coding. One involves competitive incentives and dynamic relative performance feedback, and aims to give children experience with competition in a controlled environment. The other intervention gives the same educational content but with individualistic as opposed to competitive incentives. We report preliminary results on the effects of the interventions on the willingness to enter tournaments, gender gaps, and efficiency consequences.