How much I moved: Robust biases in self-rotation perception.

Area of Science:

• Neuroscience
• Sensory Perception
• Human Navigation

Background:

• Vestibular cues are essential for sensing head acceleration and spatial orientation.
• Vestibular information integrates with proprioceptive and visual senses for navigation.
• Emerging evidence suggests auditory cues can enhance self-motion perception.

Purpose of the Study:

• To investigate the interaction between vestibular and auditory information in estimating passive rotational self-motion.
• To determine how virtual acoustic landmarks influence the perception of rotational displacements.
• To explore the effect of auditory cue presentation methods (passive vs. active) on self-motion estimation.

Main Methods:

• Two experiments were conducted with healthy participants on a Rotational-Translational Chair.
• Participants performed a self-motion discrimination task involving yaw rotations without visual input.
• Accuracy (Point of Subjective Equality) and precision (Just Noticeable Difference) of rotation amplitude estimation were measured under vestibular-only and audio-vestibular conditions.

Main Results:

• A significant overestimation bias for rotational displacements was observed across all conditions, directions, and sound generation methods.
• Neither the presence of auditory cues nor the method of sound presentation altered this overestimation bias.
• Precision (JND) and accuracy (PSE) measures indicated consistent biases in self-motion perception.

Conclusions:

• Vestibular self-motion perception is characterized by a robust overestimation bias for passive rotations.
• Auditory information, including virtual acoustic landmarks, did not significantly modulate this overestimation bias.
• This bias may serve an adaptive function, potentially aiding in the detection of critical deviations from expected movement trajectories in daily navigation.