  Virtual reality allows creating highly immersive visual and auditory
experiences, making users feel physically present in the environment. This
makes it an ideal platform to simulate dangerous scenarios, including fire
evacuation, and study human behaviour without exposing users to harmful
elements. However, human perception of the surroundings is based on the
integration of multiple sensory cues (visual, auditory, tactile, or/and
olfactory) present in the environment. When some of the sensory stimuli are
missing in the virtual experience, it can break the illusion of being there in
the environment and could lead to actions that deviate from normal behaviour.
In this work, we added an olfactory cue in a well-documented historic hotel
fire scenario that was recreated in VR, and examined the effects of the
olfactory cue on human behaviour. We conducted a between subject study on 40
naive participants. Our results show that the addition of the olfactory cue
could increase behavioural realism. We found that 80% of the studied actions
for the VR with olfactory cue condition matched the ones performed by the
survivors. In comparison, only 40% of the participants' actions for VR only
condition were similar to the survivors.
