Balancing what your eyes see with what your ears sense can be tricky when you’re on the move.
A collection of nerves, channels and fluid called the vestibular system inside your ears co-ordinates equilibrium by detecting motion from sensory inputs when moving. When you shift your position, the fluid in your ear also moves, triggering nerve messages that – along with visual information from the eyes-tell the brain what’s going on so it can react.
However, when travelling in a coach or on a boat, for example, the atypical motion experienced by the body can cause an imbalance between what the eyes are seeing (or perhaps what they aren’t seeing) and what the ears are experiencing physically.
This can also happen in reverse whereby the eyes may perceive movement visually while none is felt by the vestibular system, providing the brain with conflicting information that can’t be processed quick enough to enable the body to respond and maintain balance.