The perception of heading during eye movements

Area of Science:

• Visual neuroscience
• Human perception
• Navigation

Background:

• Heading perception is typically determined by the focus of expansion in retinal motion flow during self-motion.
• When head and eye movements occur, retinal motion patterns deviate from radial flow, complicating heading perception.
• Existing models for heading perception include extra-retinal and retinal-image based approaches.

Purpose of the Study:

• To investigate the role of extra-retinal information in heading perception during eye movements.
• To test whether heading judgments require extra-retinal signals at higher, more ecologically relevant eye movement velocities.

Main Methods:

• Heading perception was measured under conditions simulating translation with and without simulated eye movements.
• The study compared performance at slow eye movement velocities (as in prior research) and higher, more typical velocities.
• Observers judged heading while tracking a point on a simulated ground plane versus fixating a stationary point with simulated eye movement.

Main Results:

• Previous findings of similar performance at very slow eye movements were replicated.
• At higher, more naturalistic eye movement velocities, heading perception accuracy significantly decreased without extra-retinal information.
• Performance was significantly better when extra-retinal eye position information was available.

Conclusions:

• Extra-retinal information regarding eye position is essential for accurate heading perception during many real-world viewing conditions involving eye movements.
• Previous conclusions suggesting extra-retinal information is unnecessary may have been limited by the extremely slow eye movement speeds used in prior studies.