Self-motion sensitivity to visual yaw rotations in humans

Area of Science:

• Perception Psychology
• Human-Computer Interaction
• Visual Neuroscience

Background:

• Humans rely on visual cues for self-motion perception and action control.
• Understanding how visual stimulus intensity influences self-motion perception is crucial for various applications.
• Visually induced self-motion, or vection, is a key phenomenon in this area.

Purpose of the Study:

• To investigate the human ability to discriminate perceived velocities of visually induced illusory self-motion (vection) around the vertical (yaw) axis.
• To quantify motion sensitivity as a function of stimulus velocity.
• To explore factors influencing vection onset and sensitivity.

Main Methods:

• Participants performed a two-interval forced-choice task to discriminate rotational velocities of a virtual forest environment.
• Stimuli were presented on a projection screen with a wide field of view.
• Motion sensitivity was measured by determining the differential threshold at five different velocities (5-60 deg/s).

Main Results:

• Differential thresholds for circular vection increased with stimulus velocity, following a power law (exponent 0.64).
• The time to reach complete vection was longer for initial presentations compared to subsequent ones.
• Vection onset time was independent of stimulus velocity.

Conclusions:

• Human sensitivity to perceived self-motion velocity decreases as stimulus intensity increases.
• Lower differential thresholds (higher sensitivity) are associated with slower rotational velocities, potentially due to frequent real-world exposure.
• Prior visual motion exposure may facilitate vection, possibly via visual motion after-effects.