Monday, June 3, 2019

Movement That Gives You the Feels

A baseball player walks into the batter’s box. He shifts weight from front foot to back while circling the bat. Rotates his right heel into the ground. Orients his gaze to the pitcher while pointing his bat to center field. Slowly swings his bat three or four times to an imagined contact point with the ball. Then crouches lower to wait for the pitch, still shifting weight from foot to foot. What’s the point of all this seemingly useless motion?

You can see similar routines in any sport that allows an athlete a few free seconds before taking action.

Waggling the club before a golf shot.

Bouncing the ball before a free throw or tennis serve.

Doing all manner of bizarre shit before a deadlift.


Are these rehearsals for the upcoming action? Sure doesn’t look like it. Do these movements get you in the groove? Maybe so but why? And, did you actually watch the deadlifting video? Go back and watch please, show Jujimufu some respect.

Epistemic Actions

I think these movements might be what are called “epistemic actions.”

David Kirsh and Paul Maglio introduced this term as a way to distinguish between physical movements done directly in the performance of a physical task (“pragmatic actions”) and movements done to reduce the difficulty of the information processing necessary to control the task (“epistemic actions”).

Accurate motor control requires you to have information about the moving parts in the body and environment. You also need to interpret the meaning of that information so that it helps you plan the right movements. An epistemic action is one that either delivers the right information at the right time, or assists in the interpretation of that information. You might say it is a movement that gives you a good sense of “feel” about how to move.

Here’s an example of an epistemic movement that is trivially obvious – turning the eyes or head to see objects in the environment. Check out this video of Frank Lampard playing soccer with his head on a swivel.



Part of the reason he is turning so much is that he needs updates on a changing environment. But even when analyzing a static scene, such as a room full of objects, you must constantly shift your eyes back and forth to make any practical sense of the information (for example, finding where you left your keys.) The information won’t arrive passively just by staring in the right direction. Vision is therefore a very activeprocess – you need to move to perceive, and you need to move the right way to perceive the right things.

Proprioception is the same way, it is an active process, not a passive one. Many of the our movements have a primarily epistemic purpose – they are not done so much to directly accomplish a physical goal, but to create proprioceptive information that optimizes or simplifies motor control.

I think this is what the batters are doing in the box while waiting for a pitch. They are moving in a way that actively seeks all the sensory information that will help them hit the ball. They are looking for the “feel” of the position of the feet relative to the plate and the pitcher; the angle of the head; the place where they will contact the ball; and the orientation of the hands, shoulders and hips relative to the bat.

Of course these players have already built, through many years of practice, maps or representations inside their brains that have information about all of these factors, and this allows them to “feel” the right stance even in the absence of these preparatory movements. But all this representing and mapping places a burden on memory and information processing. “The best map for the world is the world itself”, therefore it is far more efficient to gather information about the body and environment right when it is needed, as opposed to constantly maintaining an internal model of that information. Epistemic actions are a way to check in with the state of the world through movement.

(By the way, the idea of “offloading” the demands of information processing to the body or environment is very consistent with the ideas about “extended mind” that I discussed in my previous post.)


So why is this interesting? Well it just is. Here’s a few more reasons.

I think a good deal of the movements seen in various forms of corrective exercise are much more epistemic than pragmatic. That is, their value consists more in feeling your body than in rehearsing actual movements you might do some day. And remember that this feel is temporary – you need to keep refreshing it through movement.

Another reason epistemic action is interesting is that it should be a caution to analyzing the technical merits of a movement with too much reliance on its biomechanical “pragmatism.” What appears to be a pragmatic bug in someone’s movement technique might actually be an epistemic feature. Put another way, some ways of moving just “feel” better, and this might be more important than how it looks to the coach. 

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