Distinctive within the extensive ecosystem of children‟s technologies available today are those for constructing and exploring digital objects – for instance by building robots and programming their behaviors. Such technologies have gained popularity as they can be both entertaining and enriching, especially when designed and used according to cognitive developmental and constructionist learning principles. The TangibleK Robotics Project has conducted three years of developmentally driven research on technology designs and learning expectations for CHERP, a robotics programming tool for kindergarteners. This thesis examines preschoolers‟ and kindergarteners‟ problem-solving and reasoning during a programming task as a function of their cognitive developmental level. Results show that while children in late pre-operations engage in meaningful programming explorations, their work differs qualitatively from that of older children transitioning into or already in early concrete operations. The findings inform discussion of developmentally differentiated learning expectations and issues to consider in future technology revisions.