We set out to test whether positive non-verbal behaviours of a virtual coach can enhance people's engagement in automated virtual reality therapy. 120 individuals scoring highly for fear of heights participated. In a two-by-two factor, between-groups, randomised design, participants met a virtual coach that varied in warmth of facial expression (with/without) and affirmative nods (with/without). The virtual coach provided a consultation about treating fear of heights. Participants rated the therapeutic alliance, treatment credibility, and treatment expectancy. Both warm facial expressions (group difference = 7.44 [3.25, 11.62], p = 0.001, [Formula: see text]=0.10) and affirmative nods (group difference = 4.36 [0.21, 8.58], p = 0.040, [Formula: see text] = 0.04) by the virtual coach independently increased therapeutic alliance. Affirmative nods increased the treatment credibility (group difference = 1.76 [0.34, 3.11], p = 0.015, [Formula: see text] = 0.05) and expectancy (group difference = 2.28 [0.45, 4.12], p = 0.015, [Formula: see text] = 0.05) but warm facial expressions did not increase treatment credibility (group difference = 0.64 [- 0.75, 2.02], p = 0.363, [Formula: see text] = 0.01) or expectancy (group difference = 0.36 [- 1.48, 2.20], p = 0.700, [Formula: see text] = 0.001). There were no significant interactions between head nods and facial expressions in the occurrence of therapeutic alliance (p = 0.403, [Formula: see text] = 0.01), credibility (p = 0.072, [Formula: see text] = 0.03), or expectancy (p = 0.275, [Formula: see text] = 0.01). Our results demonstrate that in the development of automated VR therapies there is likely to be therapeutic value in detailed consideration of the animations of virtual coaches.
Humans, Emotions, Mental Health, Phobic Disorders, Virtual Reality