Perception is the interpretation of sensory information by the brain. It's influenced at the lowest level by the instinctive drives and immediate priorities - fighting, flight, feeding and reproduction. But in humans and many other higher animals it's overridingly framed by accumulated experience.

To venture successfully into the wild, it's essential to develop a habit of quiet unobtrusive movement. Learning this takes patience, perception and practice.

The very design of much modern footwear forces us to move unnaturally, clumsily and noisily. Try walking normally in your ordinary shoes on a smooth hard surface at a quiet time of day.

Having mastered the techniques of moving quietly on the pavement, the next objective is to transfer that skill to the real ground surfaces of the wild. Some of the most challenging include squelchy mud, leaf litter both wet and dry, long grass, grit, woodland undergrowth and shingle. And of course fresh snow - it's almost impossible to walk silently in newly fallen snow more than about an inch (25 mm) thick.

We naturally tend to wave our arms in step when walking, but it's mostly a habit rather than an essential requirement for locomotion. In the wild it poses two problems.