Odours in a visual virtual environment: effects of congruency

The present study aimed to explore the effects of odours, presented together with a virtual reality (V.R.) environment, on memory and numerous aspects of perception in the context of congruency vs incongruency. We examined both effects of intended manipulation of congruency (determined by a group of olfactory experts) and the manipulation check (individual perception of congruency) between V.R. environment and olfactory conditions. 100 participants watched 5 different pleasant vs unpleasant three-dimensional 360° videos, and were randomly attributed to one of 5 groups, each exposed to a specific pleasant or unpleasant odour condition. Following the presentation of each of the 5 V.R. environments, the participants responded to 9 questions assessing various aspects of each V.R. presentation. During the second test, the participants provided self-declared memory ratings and descriptions of the content of the V.R. scenes without experiencing odours or V.R. environments. Linear Mixed Model analyses revealed that intended manipulation of congruency increased some perceived positive aspects of virtual videos. However, odours that are incongruent with visual contents also enhanced positive assessment of the V.R. environments what was further noticed in case of the manipulation check. Eventually, high level of self-declared memory of virtual videos’ details positively influenced V.R. environments’ perception.