Perception of two-dimensional, simulated ego-motion trajectories from optic flow

Area of Science:

• Neuroscience
• Perception Psychology
• Human Factors Engineering

Background:

• Ego-motion perception relies on integrating visual, vestibular, and proprioceptive signals.
• Previous research indicated accurate path perception with constant head orientation but errors when turning relative to the path.
• The role of vision in correcting or complementing vestibular perception during complex ego-motion scenarios remains unclear.

Purpose of the Study:

• To investigate whether visual information improves ego-motion path perception when vestibular signals are ambiguous or conflicting.
• To compare visual ego-motion perception with previously established vestibular perception capabilities.
• To determine how observers' orientation relative to the path and space influences trajectory perception.

Main Methods:

• Subjects viewed simulated 2D linear and curvilinear trajectories using head-mounted displays with optic flow.
• Observer orientation was manipulated: fixed in space, fixed relative to the path, or changing relative to both.
• Perceived movement was reproduced using a model vehicle, with position and orientation data recorded.

Main Results:

• Subjects accurately perceived ego-rotation (yaw) but perceived their orientation as fixed relative to the path or space.
• This misperception of orientation led to errors in trajectory perception when body rotation was incorrectly attributed to path rotation.
• Visual perception of ego-motion closely mirrored previously observed vestibular perception.

Conclusions:

• Visual ego-motion perception shares significant similarities with vestibular perception, including susceptibility to orientation-based misinterpretations.
• Conflicting orientation cues in visual or vestibular domains can lead to similar trajectory misperceptions.
• The findings highlight the complex interplay between sensory inputs and internal reference frames in ego-motion perception.