“…is well known to play a major role in any form of human-human [15,33] and human-machine interaction [26,32]. Since teaching is a inherently social activity, education sciences investigated extensively the effect of nonverbal behavior during lectures or, more in general, oral presentations (see [40,46] for extensive surveys). Two main aspects of the problem were explored: on one hand, the effect of teachers' nonverbal behavior on the impressions developed by students [2,3] and, on the other hand, the impact of teachers' nonverbal behavior on students' outcomes [12,36].…”