Walking in Circles
I am often asked about the tendency of people to walk in circles when lost. Here is an explanation of what happens.
1) If people have a steady external clue to direction, eg. the sun, the moon, a distant mountain summit, they are very unlikely to walk in circles when trying to walk in a straight line. This is true even if they are lost.
2) If people are in unfamiliar territory and they are denied an external reference to direction, for example in poor visibility or dense woodland, they will begin to walk in circles.
3) The radius of these circles varies enormously between individuals.
4) This trait can be found in other animals too, even very small ones, and has been observed 'in blindfolded birds and mice and in rotifers, ciliates, flagellates, amebas, Oscillatoria, Spirochaets, ciliated larvae of many marine in- vertebrates, spermatozoa, zoospores and spermatozoids.' [A. A. SCHAEFFER]
5) The cause of this circling does not appear to be, as has sometimes been claimed, due to 'biomechanical assymmetry' - we don't walk in circles because one leg is longer or stronger than the other. [See Note A, below] Similarly, it is not related to whether we are right or left-handed.
6) There have not been enough studies for a universally accepted explanation for why we walk in circles. One academic explanation for this tendency is that it is 'the result of accumulating noise in the sensorimotor system' [Souman et al., Walking Straight into Circles, Current Biology (2009)]
Humans, like all animals, need an external clue to direction in order to be able to follow a fixed course. Without this external reference we will deviate. These deviations from a straight course can accumulate to create a circular walking pattern.
Multiple theories exist for the reason why we deviate from a straight line, but not enough studies have been done for any one of them to emerge as triumphant.
The fascinating aspect of this topic, from a natural navigator's perspective, is that the assumption is made very widely that the external references must be very large and distant, eg. the sun. However, a large part of the art of natural navigation is found in the recognition of the smaller, closer clues, such as plants, animals, puddles etc.
This is no way invalidates any of the studies referenced above, since these are still external references, but it does highlight the cultural differences between those of us who immerse ourselves in the subject of finding our way using nature and those who look at it from a distance.
In other words, we are much less likely to get lost or walk in circles, if we pay attention to what's under our noses!
'The large variability in curvature of the blindfolded walking trajectories and the absence of a consistent bias in most participants suggest that biomechanical asymmetries did not play an important role. This conclusion was supported by further tests on the effect of biomechanical asymmetries.' [Souman et al., Walking Straight into Circles, Current Biology (2009)]
I would like to thank:
Prof Dr Peter Brugger of the Department of Neurology, University Hospital Zurich, for drawing my attention to the academic articles cited here.