If you blindfold and try to walk straight, you can't do it. You always lean to the left or right. If you keep walking, your route will be an arc. "Ghosts hit the wall" is this principle. Usually when we walk, our legs are commanded by the brain, and the brain will automatically correct the direction according to the information obtained by the eyes, so people can go wherever they want. However, if the eyes can't get outside information, the brain can't effectively control the direction of walking. Because the steps taken by people's two legs are slightly different, there is a step difference, and the distance between the two legs is more than 10 cm, which leads to the deflection of the walking direction. In this way, two feet will walk in two concentric arcs, and people will turn around. Therefore, when walking in the dark or foggy wilderness, the eyes can't receive the reference information of the surrounding scenery, and the brain can't adjust the influence caused by the step difference, so there may be a phenomenon of "ghosts hitting the wall", which is actually getting lost.