Real and visually-induced body inclination differently affect the perception of object stability

Area of Science:

• Perception science
• Human psychophysics
• Sensorimotor systems

Background:

• Object stability prediction relies on a gravity reference frame.
• Internal gravity representation is crucial for stability judgments.
• Visual and somatosensory cues contribute to gravity perception.

Purpose of the Study:

• To investigate how simulated and real body tilt influence gravity perception and object stability judgments.
• To determine if internal gravity representations bias critical angle (CA) estimations similarly across visual and vestibular conditions.
• To understand the differential weighting of visual motion and visual polarity cues in stability perception.

Main Methods:

• Measured critical angle (CA) for object stability across three experiments.
• Manipulated internal gravity representation using simulated visual tilt and real body tilt.
• Assessed perceived gravity direction and CA estimations in each condition.

Main Results:

• In simulated tilt, perceived gravity and CA deviated concordantly.
• In real tilt, body orientation affected perceived gravity but not CA.
• Visual motion and visual polarity cues are weighted differently for stability estimation.

Conclusions:

• Internal gravity representations derived from visual motion and body tilt have distinct effects on stability judgments.
• The brain differentially utilizes visual motion and visual polarity cues for estimating object stability.
• Understanding these differences is key to perceptual models of stability and orientation.