In Praise of Walking: A New Scientific Exploration

by Shane O'Mara

Stable, rhythmic movement is the core of walking, another crucial input is the system that allows foot placement without us paying continuous conscious attention to the foot itself. How does the brain solve this problem of knowing where your foot is, and then placing it against the ground, and levering you on? As we will soon see, the brain possesses an acute sense of extended space, a ‘cognitive map’ that allows you to navigate the world. But it also has an acute sense of the body that it animates. The brain engages in ‘exteroception’ (processing information about the outside world from vision and hearing), and ‘interoception’ (processing information about, for example, hunger, thirst, pain from internal organs). We also have a highly developed sense of the position of our ankle, knee and hip joints in space, and also from signals from the muscles and ligaments: this is our ‘sixth sense’ – proprioception.14 Testing your proprioceptive sense is the subject both of many childhood games and neurological tests. One simple test is touching your nose with your fingertip with your eyes closed. The margin of error here should be less than about a centimetre. Another is walking in the dark or with your eyes closed – in an obstacle-free environment this is surprisingly straightforward. Finally, stand on one leg with your eyes open, and repeat with your eyes closed. As you try to maintain an upright posture you become acutely aware of how visual input is integrated with your joint s...