Retinal curl as a functional signal for heading estimation beyond the focus of expansion.

Retinal curl serves as a key functional signal for heading estimation, causing systematic perceptual biases that depend on gaze direction.

• Why it matters: Understanding how humans perceive heading during movement is crucial for models of navigation and visual processing, yet current theories focus on recovering the Focus of Expansion (FoE), which may be complex.
• What they did: The study involved 3D heading perception tasks with simulated walking paths, manipulating retinal curl in real-time to observe its effect on perceived heading and biases, supported by neural network modeling.
• The result: Findings demonstrate retinal curl directly influences heading perception, enabling the brain to use gaze stabilization geometry for navigation, simplifying the process by treating curl as a meaningful signal.