By Joshua Brumberg
For the first day of class I like to introduce the concept that the brain is an integrative device. I ask my class to stand up with their hands at their sides and I ask them to stay still, something most students do not have a problem doing. I then ask the students to stand on one leg and remain still, this is a slightly harder task. I then ask the students to bend one knee and still keep still, at this point many people have to steady themselves, and some students will put out their hands for balance. Finally I ask the students to close their eyes and try to maintain their balance at this point most students cannot and they put their raised foot down. I then ask the class to sit back in their seats and we discuss the task.
The class easily realizes we are most stable when we have two feet on the ground and as we lift up one leg things get harder; further discussion gets them to realize that sensory inputs arriving via their visual system are being used by their brains to help maintain their balance (via descending inputs to motorneurons which activate muscles in the legs). When their eyes are closed they have to rely on proprioceptive inputs from their ankles which are slower to arrive to their brains’, which makes it harder to quickly correct deviations in balance. The ultimate realization is that different sensory (visual, proprioceptive) and motor systems do not work in isolation but in conjunction, which is a primary focus of the class.
Dr. Joshua Brumberg is the Dean of the Sciences at the Graduate Center and a Professor of Psychology at the Graduate Center and Queens College.
Sakina Laksimi Morrow
Thank you for sharing this interesting and unique activity. I was wondering if you could address how you might adapt or change this activity for students who are not physically capable of doing these tasks (for example amputees, students in wheelchairs, blind students etc)? More broadly, what are the pedagogical implications of an activity designed with a particular body in mind? Thank you!
Unfortunately this particular experiment only works for those who can stand up. There is an analogous upper body experiment.
You ask for a student volunteer and then ask someone to provide you with a heavy bag with a strap that can be grabbed by a hand.
Ask the volunteer to hold out their hand and keep it parallel to the ground and then ask them to hold their hand steady as you place the bag strap in their hand – they should have no problem keeping their arm straight.
Then ask the volunteer to do the same thing with their eyes closed – when you place the strap in their hand you will see the hand go down and then return to the outstretched position.
In the case with the eyes open there is an anticipation and the visual system is sending information to the motor system to pretense the arm muscles – in the eye closed condition the subject must rely on stretch receptors that get activated in the muscle and this is a slower pathway and their is no anticipation so the arm goes down before being brought back up.
In this example someone in wheelchair could do it. A blind person could do the standing up exercise – they would have a harder time balancing but the result would be the same. In the case of the arm exercise you would only need one example instead of the whole class and if possible I would rather involve the whole class.