Walking: It’s Harder Than You Think
Anybody who has ever played pin the tail on the donkey knows how hard it is to walk in a straight line blindfolded, especially while dizzy. It is actually impossible for us to stay on a straight path while blind-folded. Jan Souman, a German scientist, conducted an experiment to see if someone could walk in a straight line while blind-folded. He found that when the participant had no visual landmarks to work off of they ended up walking in circles, even though they thought that they were staying on a straight path.
But what exactly is a straight line? Well, according to the free dictionary, “a line…traveling in a constant direction.” In other words, having zero deviation throughout the entirety of the trip. In Jan Souman’s large scale experiment, where people were told to walk for up to an hour in a wide open area, a straight line meant not going in circles and staying in relatively one direction. However, in my much smaller scale experiments, where the participants will walk across a gym or small park area, a straight line will be the shortest distance between two points. In other words, if the participant takes a curved path and still reaches the target area it will not be considered a straight line. This is because my participants will be traveling a much shorter distance, and will have less room for error.
In my experiment I will be measuring how far the participant deviates from their path. They will have a four foot wide end point and in order to hit it they will have to remain on a near perfectly straight path. After each trial it will be measured, in feet, how far they deviated from the target area. I will do four total trials on each person, two without sound and two with the sound. I will then compare to see if there is any real effect of having the sound versus no sound.
So far I have talked a lot about walking in a straight line, but what exactly is walking? According to the free dictionary it is “To move over a surface by taking steps with the feet at a pace slower than a run.” Walking is a type of controlled falling where you let your body fall but catch yourself with your leading leg. It is also described as an“inverted pendulum” by F. Lacquaniti, R. Grasso, and M. Zago in the article Motor Patterns in Walking where we see the center of mass almost vault over the supporting leg. However, walking in itself is not perfect. Walking is a fluid motion where a lot of muscles have to make a lot of movements. Some of them are bound to make mistakes. If you are not blind-folded you could easily fix these errors and stay straight. However, once you are blind-folded fixing these mistakes doesn’t happen quite as often and you will veer off path. Even if you don’t have a blindfold on, if there is no clear visual landmark for you to work off of, i.e. the sun, you will veer of path just as easily.
If possible my experiment will be done indoors to avoid then sun piercing through the blindfold and acting as a visual landmark. If this is not possible then I will attempt to do my research on a cloudy day, or account for the sun in the results. Also, if I can not preform mt experiment in a gym I will attempt to do it on a flat surface such as a football field. The definition of walking noted above will be the same I will be using in my tests, a slow controlled movement over a surface.
In my experiment I will be using sounds in an attempt to replace the visual aid that is needed to stay straight. However, I will only be using distinct sounds, such as an alarm beeping. The sounds I will use will be as clear and distinct as possible in an attempt to set it apart from any background or white noise. I will do multiple trials on each participant with the noise coming from the middle of the target area. I will then mark down how far they missed the target by, and if there is any difference whether or not there is a sound.
F. Lacquaniti, R. Grasso, M. Zago. Motor Patterns in Walking. August 1999. 7 March 2012.
Krulwich, Robert. A Mystery: Why Can’t we Walk Straight. 7 March 2012.