  Understanding validity of user behaviour in Virtual Environments (VEs) is
critical as they are increasingly being used for serious Health and Safety
applications such as predicting human behaviour and training in hazardous
situations. This paper presents a comparative study exploring user behaviour in
VE-based fire evacuation and investigates whether this is affected by the
addition of thermal and olfactory simulation. Participants (N=43) were exposed
to a virtual fire in an office building. Quantitative and qualitative analyses
of participant attitudes and behaviours found deviations from those we would
expect in real life (e.g. pre-evacuation actions), but also valid behaviours
like fire avoidance. Potentially important differences were found between
multisensory and audiovisual-only conditions (e.g. perceived urgency). We
conclude VEs have significant potential in safety-related applications, and
that multimodality may afford additional uses in this context, but the
identified limitations of behavioural validity must be carefully considered to
avoid misapplication of the technology.
