Why do people sway more when they close their eyes?

People tend to sway more when they close their eyes because visual input is a key component of maintaining balance. When the eyes are closed, the brain loses a significant source of information about the body's position in space, relying more heavily on the vestibular and proprioceptive systems. This can lead to increased instability and swaying as the body adjusts to the lack of visual cues. Additionally, without visual references, one's sense of orientation can become less reliable, contributing to the swaying motion.