In this paper, we present an experiment in the context of a child-robot interaction where we study the influence of the child-robot spatial arrangement on the child’s focus of attention and the perception of the robot’s performance. In the “Co-Writer learning by teaching” activity, the child teaches a Nao robot how to handwrite. Usually only face-to-face spatial arrangements are tested in educational child robot interactions, but we explored two spatial conditions from Kendon’s F-formation, the side-by-side and the face-to-face formations in a within subject experiment. We estimated the gaze behavior of the child and their consistency in grading the robot with regard to the robot’s progress in writing. Even-though the demonstrations provided by children were not different between the two conditions (i.e. the robot’s learning didn’t differ), the results showed that in the side-by-side condition children tended to be more indulgent with the robot’s mistakes and to give it better feedback. These results highlight the influence of experimental choices in child-robot interaction.