  A cluster of research in Affective Computing suggests that it is possible to
infer some characteristics of users' affective states by analyzing their
electrophysiological activity in real-time. However, it is not clear how to use
the information extracted from electrophysiological signals to create visual
representations of the affective states of Virtual Reality (VR) users.
Visualization of users' affective states in VR can lead to biofeedback
therapies for mental health care. Understanding how to visualize affective
states in VR requires an interdisciplinary approach that integrates psychology,
electrophysiology, and audio-visual design. Therefore, this review aims to
integrate previous studies from these fields to understand how to develop
virtual environments that can automatically create visual representations of
users' affective states. The manuscript addresses this challenge in four
sections: First, theories related to emotion and affect are summarized. Second,
evidence suggesting that visual and sound cues tend to be associated with
affective states are discussed. Third, some of the available methods for
assessing affect are described. The fourth and final section contains five
practical considerations for the development of virtual reality environments
for affect visualization.
