The Blind-Spot Between High-Level Decision and Low-Level Muscle Movement

A few days ago, I was laying in bed, trying to fall asleep without much success. After reading for a while, I turned off the light and ended up on my stomach, with my head resting on my folded arms. I was getting sleepy, so I decided to get in a more comfortable position before I fell asleep. But right before I could physically execute my decision, I thought about how I was going to do it.

Not as easy as it sounds. I knew for certain that I could get out of that position – I’ve probably done it thousands of times – but I just didn’t know precisely how I would do that in advance. How would I move? Would I shift my weight this way, or that way? Support myself on my right elbow? Try to spin and then use my back muscles to sit up? I had a vague idea of how it went, but the details truly stumped me, and I just laid there trying to figure it out.

Why is it so hard to predict in high-resolution totally mundane movements that we’ve done a thousand times?

Is it because we can do most of them without paying attention, and so we’re simply not used to thinking about it. Maybe with practice I could improve?

Is it because there’s an evolutionary advantage to not cluttering our conscious mind with it, so we’re not equipped on the hardware level to precisely and reliable forecast complex – if banal – physical movements?

Or maybe it’s because even the motor centers of our brain don’t know the details in advance, and rely on many feedback loops to adjust things in real-time once the sequence has started? After all, even when doing familiar things, you never move in exactly the same way, so there’s got to be some room for improvisation and adjustments.

It could be that the ‘key’ to the puzzle of doing the movements is stored in a type of memory – commonly known as ‘muscle memory’ – that can only be ‘read’ sequentially (just like you can’t remember the notes of a melody out of order) and needs to be played back physically. You can’t just simulate it in your brain.

I’m trying to think about precisely how I’m going to get up from this chair, and I just can’t do it. Then I do it and it seems obvious (twist my back to the right and swing my arm around the back, then shift my weight to the right buttock, move my right feet back and then push up with the legs, which pushes the chair back, stabilize, done), but it really wasn’t.

Once you’ve done the exercise a few times while paying attention, you can better predict what you’re going to do the next time, but it’s probably just because you’ve stored a new memory of the movement in addition to the original ‘muscle memory’. If you try the whole exercise again with a different movement, it’s just as hard as the first time.

Sometimes when I look at myself or someone else move, I’m just amazed at human motor skills. It’s so familiar, yet so alien. It’s like water to a fish.

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One Response to “The Blind-Spot Between High-Level Decision and Low-Level Muscle Movement”

  1. space bar Says:

    It is interesting how this may relate to prosthetic devices (arms, legs)

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