How your sense of direction drifts
When familiar landmarks disappear, you lose an outside reference for checking whether you are still heading straight. Instead, you rely more on dead reckoning: estimating your position and direction from your own movement since the last known point. Each step contributes a little information, but none is perfectly measured.
Your brain combines signals from your legs, joints, balance system, and vision. These signals help estimate how far you have moved and how your body has turned. But a barely noticeable curve or turn can be hard to detect, especially when the surroundings offer no stable visual cue to compare against.
Small errors can become a large detour
Imagine trying to walk straight through fog. If each step angles slightly to one side, the next step begins from a position already off course. The error carries forward, and later estimates are based on the altered path. You may feel that you are continuing in one direction even as your route bends.
This is not necessarily a deliberate choice or a failure to pay attention. It is a limitation of navigation based on accumulating estimates: without a landmark to correct the drift, “straight ahead” can gradually shift without feeling different. The practical consequence is simple—when visibility is poor, checking a compass, map, or fixed landmark can provide the external correction your body’s own signals cannot reliably supply.
