The visual perception coordinate system uses axes defined by the earth, trunk, and vision

Area of Science:

• * Neuroscience
• * Human Perception
• * Visual Neuroscience

Background:

• * Understanding how the human brain processes spatial orientation is crucial for fields like robotics and virtual reality.
• * Previous research indicates that visual perception is influenced by body posture and internal reference frames.

Purpose of the Study:

• * To investigate how young adults orient lines relative to internal and external reference frames under varying head and trunk postures.
• * To determine the influence of head and trunk orientation on the accuracy of perceived vertical and oblique lines.

Main Methods:

• * Eight young adults adjusted a visual line on a display to match internal vertical, horizontal, or oblique axes.
• * Tasks were performed in a dark room with participants in erect and varied head and trunk postures.
• * Errors in line adjustment were measured to assess perceptual accuracy.

Main Results:

• * Lowest errors occurred when setting lines to internal vertical (frontal plane) and oblique lines (horizontal plane) with varied postures.
• * The oblique effect persisted across different head and trunk orientations.
• * Constant errors in line alignment showed directional differences based on display side but not on internal axes.

Conclusions:

• * The visual perceptual system relies on internally specified vertical and visual horizontal references for object orientation.
• * The preservation of the oblique effect suggests integration of internal gravitational cues with visual input.
• * Body posture significantly influences spatial perception accuracy, highlighting the interplay between proprioception and vision.