Virtual Reality (VR) is increasingly used in a variety of contexts (ranging from occupational learning to psychotherapy) with the goal to immerse users in lifelike but controlled situations. Users typically describe experiencing the virtual world "as if they were there", but are of course well aware of the situation's artificiality. In hindsight, however, the distinction between VR and reality may become blurry: In our recent study, participants saw objects in reality, in VR and on a computer monitor, and, when later asked to recall in which situation they saw each object, tended to more frequently confuse VR and reality compared to the computer monitor and reality. These source memory errors may contribute to the generalization of psychotherapeutic treatment effects obtained in VR, but they may also constitute a negative side effect of VR usage that needs further investigation.

Rubo, M., Messerli, N. & Munsch, S. (2021). The human source memory system struggles to distinguish virtual reality and reality. Computers in Human Behavior Reports, 100111. doi: https://doi.org/10.1016/j.chbr.2021.100111