Understanding Motion Sickness Cause

Motion sickness arises from a mismatch in sensory information received by the brain.

Sensory Systems Involved

Two key systems are involved:

• Visual System: Provides information about the environment through sight.
• Vestibular System: Located in the inner ear, it senses motion, head position, and spatial orientation.

The Conflict Principle

Motion sickness occurs when the information from the visual system and the vestibular system do not align, creating a sensory conflict. For example, while in a car, your inner ear might sense movement (acceleration, turns), but your eyes might see a stable interior, leading to conflicting signals.

Evaluating the Options

• Option (a) is incorrect because losing the vestibular sense causes balance issues, not typically motion sickness itself.
• Option (b) is incomplete; relying solely on visual information isn't the direct cause, but rather how it conflicts or fails to match other senses.
• Option (c) describes a situation where senses align, which prevents motion sickness.
• Option (d) accurately describes the core reason for motion sickness: a conflict between visual and vestibular system inputs.

Therefore, motion sickness happens specifically when the visual system and vestibular system are in conflict.