Walking straight without a compass: why people walk in circles and how to prevent it

With every step you deviate a tiny bit – because the ground is uneven, because you avoid a branch, because one leg lands slightly differently. Without an outside reference the brain does not notice these errors, and they add up to a curve. Researchers led by Jan Souman showed in 2009 that people in a forest under an overcast sky and in the desert without the sun repeatedly walked in circles, but fairly straight with the sun visible.

A fixed point in the distance replaces the missing reference. If you walk straight towards a tree, you keep correcting without noticing. Two points one behind the other are even better: as long as they stand in line for you, you are on the line – if they shift against each other, you have drifted sideways.

Looking back works the same way, only in reverse. The sticks or trees behind you must form a straight row. If the row curves, you know which way you are drifting and can steer against it.

Choose targets you cannot mix up: a tree with a striking shape, a pale rock, a gap in the forest. A target that disappears among a hundred identical spruces on the way does not help. Better short legs with clear targets than long legs with uncertain ones.

In pairs you are much more precise. The person in front walks until they are just still visible. The person behind stands on the line, looks over the previous points and waves the one in front left or right until they stand exactly on the line. Then the rear person moves up. Agree on clear signs beforehand.

You do not go around obstacles by feel. Step off at a right angle and count your paces, then pass the obstacle in the old direction, and then walk the same number of paces back. Or sight a point on the far side that lies exactly on your line and walk around to it.

Even with the best technique you will not arrive exactly. That is why you choose a direction in which a wide catching feature lies that you cannot miss: a road, a large stream, a long forest edge. Decide beforehand the longest you will walk. If you have not reached the catching feature by then, stop and think again.

Before you set off at all, there is the STOP rule. If someone knows where you are, staying at a visible place is often the better choice. In steep, rocky terrain paths and terrain decide the route – walking straight through there can be life-threatening. And at night you do not walk through unknown terrain.

The technique pays off wherever there are no paths and the terrain looks similar: in forest, scrub, on wide plains. It is especially valuable when you have found a direction with the sun, stars or natural signs and now have to hold it for a long time.

With a compass the same technique works much more precisely. Without any reference – in thick fog on snow or on a dark night – it reaches its limits. Then stopping is often better than going on.

The common belief that people walk in circles because one leg is longer was not confirmed by the 2009 study: the circles went sometimes left, sometimes right, even for the same person. It is the many small, random errors that add up.

A good practice game for children and adults: on a meadow, choose a target, set off blindfolded and see where you end up. Then do the same with an intermediate target. Anyone who has seen the difference once no longer trusts their feeling in the forest.