Why does active movement help people adapt to prism spectacles more than passive movement?

Active movement facilitates faster and more effective adaptation to prism spectacles because it provides the necessary conditions to resolve sensory discrepancies through perceptual learning.1

When wearing prism spectacles, there is a conflict between the visual location of an object and its felt position. Adaptation occurs as the brain re-evaluates sensory information—such as signals from receptors responding to tension in skeletal muscles—to reconcile these conflicting inputs.1

Active, self-initiated movement is critical because it generates the motor signals and sensory feedback required for this re-evaluation. In contrast, passive movement fails to provide the same motor-nerve discharge, leaving the brain without the necessary information to calibrate the relationship between seen and felt positions. This process mirrors early perceptual development; research, such as that by Richard Held, demonstrates that active movement is essential for developing normal visually guided behavior, whereas passive exposure to identical visual stimuli does not yield the same functional results.21