Subjective fear in virtual reality: a linear mixed-effects analysis of
skin conductance
Abstract
The investigation of the physiological and pathological processes
involved in fear perception is complicated due to the difficulties in
reliably eliciting and measuring the complex construct of fear. This
study proposes a novel approach to induce and measure subjective fear
and its physiological correlates combining virtual reality (VR) with a
mixed-effects model based on skin conductance (SC). Specifically, we
developed a new VR scenario applying specific guidelines derived from
horror movies and video games. Such a VR environment was used to induce
fear in eighteen volunteers in an experimental protocol, including two
relaxation scenarios and a neutral virtual environment. The SC signal
was acquired throughout the experiment, and after each virtual scenario,
the emotional state and fear perception level were assessed using
psychometric scales. We statistically evaluated the greatest sympathetic
activation induced by the fearful scenario compared to the others,
showing significant results for most SC-derived features. Finally, we
developed a rigorous mixed-effects model to explain the perceived fear
as a function of the SC features. Model-fitting results showed a
significant relationship between the fear perception scores and a
combination of features extracted from both fast- and slow-varying SC
components, proposing a novel solution for a more objective fear
assessment.