Underlying Working Mechanisms of Virtual Reality Exposure: Exploring the Role of Fearful Expectancies and Habituation.

While research has primarily focused on establishing the efficacy of virtual reality (VR) exposure, relatively scant attention has been paid to the underlying working mechanisms that drive the effects. The present study examined the role of fearful expectancies and fear reduction (habituation) in VR exposure. Fearful expectancies were measured before, during (retrospectively), and after a VR exposure session in 121 participants with elevated fear of spiders. In addition, skin-conductance and heart rate were measured throughout the exposure session to examine fear reduction within the exercises and across the session. Fearful expectancies decreased after VR exposure. Larger decreases were associated with better outcomes 1 week (in the verbal and behavioral measures) and 3 months (in one of the verbal measures) after exposure. Levels of expectancies during exposure were not associated with the outcome. We did not find evidence that expectancies about own reactions were better testable in VR exposure than expectancies about the spider. Fear reduction within the exercises or across the session did generally not predict VR exposure outcome. It is recommended to focus on various operationalizations and experimental manipulations of the mechanisms, as well as to compare these mechanisms between VR and in vivo exposure in future research.