Kindergarten Assistive Robotics (KAR) is an innovative tool that promotes children's development through social interaction. This study describes how KAR assists kindergarten educational staff in the teaching geometrical thinking, one of the aspects of spatial cognition by engaging the children in play-like interaction. Children's reactions and performance were video-recorded for analysis. Most children exhibited positive interaction with the robot and demonstrated a high level of enjoyment when interacting with it. Our results show that the children's performances on a spatial task were improved while they “played” with robot. To measure children's learning we developed a novel measure of cognitive learning, which we call “velocity of learning”. This study demonstrates the feasibility and expected benefit of incorporating KAR in pre-school education.