Pierre Chalfoun Claude Frasson Optimal Affective Conditions for Subconscious Learning in a 3D Intelligent Tutoring System. 39-48 2009 HCI (4) http://dx.doi.org/10.1007/978-3-642-02583-9_5 conf/hci/2009-4 db/conf/hci/hci2009-4.html#ChalfounF09