The study aimed to step into two-person (teacher-student) educational neuroscience. We describe a physiological marker of cortical hemodynamic correlates involved in teacher-student interactions during performance of a classical teaching model, the Socratic dialog. We recorded prefrontal brain activity during dialog execution simultaneously in seventeen teacher-student pairs using functional near-infrared spectroscopy (fNIRS). Our main finding is that students, who successfully transferred the knowledge, showed less activity than those who not showed transfer. Correlation analysis between teacher and student activity indicate that in successful educational dialogs student and teachers "dance at the same pace". This is the first study measuring simultaneously brain activity of teacher-student interactions and paves future investigations of brain networks involved in complex educational interactions. (Contains 5 figures and 3 tables.)