Hand-Foot Coordination 3: Phase Transition During Walking and Grasping Affected by Subsequent Action
It’s a well-replicated finding…
… that people tend to grasp objects ipsilateral to their stance leg. This is particularly interesting because such in-phase coordination is not what we typically do when walking. Think about it, you swing your upper and lower limbs in an anti-phase fashion, right? Well then, why do we tend to break out of this pattern in order to grasp with the same leg and arm thrust forward? Well… this study offers more insight into interlimb dynamics by looking at why we behave in such a pattern. You see, I hypothesized that this phase transition was due to our planning of the subsequent post-grasp movement. What we found was that when participants were instructed to grasp an object and then return to their starting position, they would often remain in an anti-phase pattern. So, breaking out of that pattern, as was often replicated in past research, was likely due to the participant’s plan to continue walking forward!
Design Implications
Phase transitions and when they happen are important to consider, because our stability drastically changes within each phase. Asking why we express patterns of behavior in certain physical contexts allows us to better predict and model human movement. Often, our brains have efficient ways of executing tasks, or at least they have familiar ways of executing tasks, and so algorithms and technologies that consider and accommodate existing cognitive processes and their accompanying physical movements will have an advantage. Notably, robotics could stand to be better informed by such a line of work, as well as advanced prosthetics.
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Photo by Pavel Danilyuk
Photo by Noelle Otto