Some tutoring systems, especially ones aimed at children, use animated characters to heighten the learner's sense of engagement. Such enhancements are in fact essential for systems aimed at learners with disabilities like deafness (where mouth and tongue movements of the virtual agent observed by the learner can help with articulation), autism, or aphasia (Massaro et al. 2012; Cole et al. 2007). As well, if tutoring is aimed specifically at training interpersonal skills, implementation of life-like characters (virtual humans) becomes an indispensable part of system development (e.g., Core et al. 2006; Campbell et al. 2011).