4 ms·

The Brain Uses Calculus to Control Fast Movements

2 points by theafh 4y ago

elmerfud 4y ago
The brain uses calculus or calculus describes/explains fast movement control.
- mannykannot 4y ago
  I go with the latter: IMHO it is a category error to confuse the symbolic manipulation of abstract symbols for physical processes, even if the symbols are intended to stand for quantitative data about those physical processes.
joezydeco 4y ago
Dogs have been integrating parabolic curves since the first tennis ball was thrown.
- Someone 4y ago
  I think you mean extrapolation, not integration, but that is unlikely. I do not know whether it has been tested on dogs, but the behavior of human ball catchers can be described by a simpler algorithm. Extrapolation would compute where and when the ball would land and then move one’s hand towards that location. A simpler algorithm that we think humans use is to move in such a way that the ball stays in the same location in one’s visual field. So, if the ball moves up in your visual field, move away from the ball. If it keeps moving up, move faster. If it starts dropping down, slow down. Similarly, if the ball moves left/right/down, move left/right/towards the ball. If you manage to do that, the ball will eventually hit your eye. For dogs, it then is a small last-ditch change to make the ball land in their mouth instead. That algorithm never uses the ball’s distance or speed, doesn’t require one to know that gravity accelerates the ball in a particular direction, and doesn’t compute where or when it will be caught. I think https://psycnet.apa.org/record/1994-36011-001 https://psycnet.apa.org/record/1994-36011-001 (paywalled) describes something like that. For humans catching a ball in one’s hand or kicking a ball, it’s a bit more difficult, but I doubt they do the seemingly necessary extrapolation of the ball’s path plus trigonometry to compute shoulder and elbow angles.
  - joezydeco 4y ago
    Perhaps you're right, but I saw it as integration. The ball is falling to earth at Vf=Vo+1/2at^2, the dog integrates to get the velocity Vf and thus position to find the point in space to run/jump and time his catch in mid-air.

2 points by theafh 4y ago

elmerfud 4y ago

The brain uses calculus or calculus describes/explains fast movement control.

mannykannot 4y ago
I go with the latter: IMHO it is a category error to confuse the symbolic manipulation of abstract symbols for physical processes, even if the symbols are intended to stand for quantitative data about those physical processes.

joezydeco 4y ago

Dogs have been integrating parabolic curves since the first tennis ball was thrown.

Someone 4y ago
I think you mean extrapolation, not integration, but that is unlikely. I do not know whether it has been tested on dogs, but the behavior of human ball catchers can be described by a simpler algorithm. Extrapolation would compute where and when the ball would land and then move one’s hand towards that location. A simpler algorithm that we think humans use is to move in such a way that the ball stays in the same location in one’s visual field. So, if the ball moves up in your visual field, move away from the ball. If it keeps moving up, move faster. If it starts dropping down, slow down. Similarly, if the ball moves left/right/down, move left/right/towards the ball. If you manage to do that, the ball will eventually hit your eye. For dogs, it then is a small last-ditch change to make the ball land in their mouth instead. That algorithm never uses the ball’s distance or speed, doesn’t require one to know that gravity accelerates the ball in a particular direction, and doesn’t compute where or when it will be caught. I think https://psycnet.apa.org/record/1994-36011-001 https://psycnet.apa.org/record/1994-36011-001 (paywalled) describes something like that. For humans catching a ball in one’s hand or kicking a ball, it’s a bit more difficult, but I doubt they do the seemingly necessary extrapolation of the ball’s path plus trigonometry to compute shoulder and elbow angles.
- joezydeco 4y ago
  Perhaps you're right, but I saw it as integration. The ball is falling to earth at Vf=Vo+1/2at^2, the dog integrates to get the velocity Vf and thus position to find the point in space to run/jump and time his catch in mid-air.