Cues from the vestibular system are generally weak in comparison to other senses, especially vision. For example, a common danger for a skier buried in an avalanche is that he cannot easily determine which way is up without visual cues to accompany the perception of gravity from the vestibular system. Thus, the vestibular system functions well when providing consistent cues with other systems, including vision and proprioception. Mismatched cues are problematic. For example, some people may experience vertigo when the vestibular system is not functioning correctly. In this case, they feel as if the world around them is spinning or swaying. Common symptoms are nausea, vomiting, sweating, and difficulties walking. This may even impact eye movements because of the VOR. Section 8.4 explains a bad side effect that results from mismatched vestibular and visual cues in VR.