You are asked to pick up a coffee and move it to the other side. How much would you let the coffee reach the edge? What may seem like a simple question is the topic of experimentation and contemplation for Dagmar Sternad, professor of Biology, Electrical and Computer Engineering, and Physics, and C.J. Hasson, postdoctoral researcher at Northeastern University.
The act of picking up a cup of coffee is the result of physiological coordination by multiple systems. The amount of margin one keeps between the coffee inside a cup and the edge of the cup to prevent it from spilling is, according to them, significant of the variability in the environment that the person feels. Sternad and Hasson conducted a study at the Action Lab of the University where the participants were asked to take a virtual cup filled with liquid from one point to another for two seconds using a manipulandum, a large robotic arm. These two seconds are crucial to understand the individual and had multiple possibilities: the person could move quickly for the first second and slowly for the second, slowly for the first and quickly for the second, or slow for half a second and quickly for the other one and half seconds. Quite similar to what happens in real life, the robotic arm would generate sensations of weight of the cup and sloshing of the liquid within it.
The results of the study were interesting. They concluded that the ones who let the liquid go to a larger extent to the edge of the cup would have a lesser safety margin which meant that they came from environments where there was more consistency. The ones who came from a variable environment had a larger safety margin for their cups. These findings have important implications in assessing elderly patients and patients of motor disorders.
N Malavika Mohan