The effect of avatar deviations on upper body and head motion in Virtual Reality

Abstract

This study investigates how deviations in avatar motion influence user motion in virtual reality (VR), specifically focusing on upper body and trunk motion in a virtual environment (VE). Previous research showed that user motion can be altered via the avatar follower effect, in which avatar deviations are followed by users. This is the first work exploring this effect for a deviation including the head. The primary objective was to explore whether these deviations could subconsciously guide user motions, potentially contributing to real-time motion sickness reduction in automated vehicles.
The experiment involved participants performing seated lateral leaning tasks where they were instructed to touch virtual goals with their heads. During some trials, the avatar unexpectedly deviated from the user's intended motion.
The results revealed that contrary to expectations, the avatar follower effect did not occur. Instead, an opposing effect was observed where participants' motions contradicted the avatar's deviations, particularly when the avatar stopped prior to the instructed goal. This effect was not influenced by the user's perspective (first or third person) or the scoring mechanism used in the game. However, individual personality traits, such as a tendency for autonomy or a focus on rewards, did affect the strength of the opposing effect.
These findings suggest that using avatar deviations to guide upper body and head motion in VR may not be effective, thus unsuited for applications such as motion sickness prevention in automated vehicles.