People tend to walk around in circles.

From Daily Mail:

It's a recurring scene in desert movies - a group of lost people try to find their way through the dunes but end up walking round in circles.

Now scientists have shown that the old cliché really is true, and that without help from the sun or stars people are unable to walk in a straight line.

Researchers in Germany left six volunteers in a forest and asked them to keep going in the same direction. On cloudy days - with no sun to guide them - the volunteers ended up walking in circles and crossing their paths without realising it.

In a second experiment, volunteers were left in the Sahara for several hours with water and food.

Again, they were able to keep to a straight path only when the sun was visible. As soon as it went behind clouds they wandered aimlessly in loops.

Dr Jan Souman, who led the study, said: 'Those stories about people who end up walking around in circles when lost are true.

'People cannot walk in a straight line if they do not have absolute references, such as a tower or a mountain in the distance or the sun or moon, and often end up walking in circles.'

[...] Dr Souman, of the Max Planck Institute for Biological Cybernetics in Tubingen, added: 'One explanation offered in the past for walking in circles is that most people have one leg longer or stronger than the other - which would produce a systematic bias in one direction.'

But the researchers disproved that by showing that blindfolded volunteers walked in circles but without any preference for going clockwise or anti-clockwise.