In this paper we present a serious game, Lewispace, where we focus on measuring and using Electroencephalograms in order to detect how the learner reasons in the game. We track learner’s reasoning according to different regions of the brain. Four standard lobes were taken into consideration: frontal, parietal, occipital and temporal. Each lobe was measured for each participant. We also studied the lobes measures distribution for all the participants. We found that some regions are more related to learner’s vision and reflexion during the game and this could be an indice that the learner follows the correct reasoning process. Primary results show that our game enhance learners’ performance. Moreover, the learners use almost occipital lobe to visualize the task presented in the game and the frontal lobe for the reasoning process.