(Gavin Ritz 2011.04.18.11.10NZT)
What exactly is the catcher
controlling?
Space-time.
What is space-time?
I don’t want to
give you the answers Rick because
you don’t Trust my answers.
Answer this then we will
be moving to get on the same page.
Let me suggest a
wonderful book by John Wheeler
called “Journey into Space-Time”
[From Rick Marken (2011.04.17.2115)]
Gavin Ritz (2011.04.18.11.10NZT)
GR: What exactly is the catcher controlling?
There are several hypotheses regarding what a real fielder (or
catcher) is controlling when they move to catch a fly ball. One
hypothesis is that the fielder is controlling the optical trajectory
of the ball, an trying to keep it linear (this is called the Linear
Optical Trajectory hypothesis). Another hypothesis is that the
controlled variable is vertical optical acceleration and lateral
angle. My hypothesis is that the controlled variable is vertical
optical velocity and lateral angle. So far, my hypothesis fits the
data best, particularly in situations where the actual trajectory of
the ball (or object to be caught, such as a Frisbee) results in
disturbances that "push" the alternative variables (optical trajectory
and vertical optical acceleration) away from their reference states.
I don�t want to give you the answers Rick because you don�t Trust my
answers.
I don't trust anyone's answers including my own. That's why I do
research to test my "answers". Trust but verify;-)
Answer this then we will be moving to get on the same page.
OK, I answered it. Are we on the same page now?
Let me suggest a wonderful book by John Wheeler called �Journey into
Space-Time�
Thanks.
Best
Rick
--
Richard S. Marken PhD
rsmarken@gmail.com
www.mindreadings.com
Rick,
Would there be any different coaching tips you would give for someone learning to catch a flyball based on the different models for what is attended to?
David
----- Original Message ----- From: "Richard Marken" <rsmarken@GMAIL.COM>
To: <CSGNET@LISTSERV.ILLINOIS.EDU>
Sent: Monday, April 18, 2011 12:15 AM
Subject: Re: Flyball
[From Rick Marken (2011.04.17.2115)]
Gavin Ritz (2011.04.18.11.10NZT)
GR: What exactly is the catcher controlling?
There are several hypotheses regarding what a real fielder (or
catcher) is controlling when they move to catch a fly ball. One
hypothesis is that the fielder is controlling the optical trajectory
of the ball, an trying to keep it linear (this is called the Linear
Optical Trajectory hypothesis). Another hypothesis is that the
controlled variable is vertical optical acceleration and lateral
angle. My hypothesis is that the controlled variable is vertical
optical velocity and lateral angle. So far, my hypothesis fits the
data best, particularly in situations where the actual trajectory of
the ball (or object to be caught, such as a Frisbee) results in
disturbances that "push" the alternative variables (optical trajectory
and vertical optical acceleration) away from their reference states.
I don�t want to give you the answers Rick because you don�t Trust my
answers.
I don't trust anyone's answers including my own. That's why I do
research to test my "answers". Trust but verify;-)
Answer this then we will be moving to get on the same page.
OK, I answered it. Are we on the same page now?
Let me suggest a wonderful book by John Wheeler called �Journey into
Space-Time�
Thanks.
Best
Rick
--
Richard S. Marken PhD
rsmarken@gmail.com
www.mindreadings.com
[From Rick Marken (2011.04.18.0900)]
Rick,
Would there be any different coaching tips you would give for someone
learning to catch a flyball based on the different models for what is
attended to?
Hi David
Not really. I did (and continue to do) the 'object interception"
research as an illustration of what I think basic research on PCT
might look like. I think this research can be used to illustrate what
a controlled variable _is_, how one can go about testing hypotheses
about what variables are being controlled in a particular behavioral
situation and how to use modeling as an intrinsic part of the research
process.
I don't think the specific results of the research would be useful to
a coach, mainly because it's possible that different people might
control different perceptions in these circumstances. So far it looks
like everyone does seem to control vertical optical velocity and
lateral optical angle, but some might use different variables or it
may be that the "true" controlled variables in this situation are
similar but not identical to vertical optical velocity and lateral
optical angle.
What I think could be useful for coaches in general is just an
understanding that the behavior they see people performing represents
the coach's view of the side effects of control of perception. So to
teach a skill you don't show a person what observable behavior to
produce; you try to tell them what kind of perceptions to produce for
themselves. A forehand in tennis, for example, is, from the point of
view of the player, a set of mainly proprioceptive and some visual
perceptions, that are controlled. A good coach would, I believe, try
to describe what the player is supposed to try to "feel" (orientation
of the arm and wrist, the movement of the arm and wrist relative to
the body, etc) and see (the face of the racket oriented perpendicular
to the ground as it strikes the ball) in order to produce the intended
result (forehand smash going 6 inches over the net).
Best
Rick
On Mon, Apr 18, 2011 at 5:33 AM, davidmg <davidmg@verizon.net> wrote:
--
Richard S. Marken PhD
rsmarken@gmail.com
www.mindreadings.com
[From Bill Powers (2011.04.18.0840 MDT)]
DG: Would there be any different
coaching tips you would give for someone learning to catch a flyball
based on the different models for what is attended to?
Rick Marken: So far, my
hypothesis fits thedata best, particularly in situations where the actual trajectory of
the ball (or object to be caught, such as a Frisbee) results in
disturbances that “push” the alternative variables (optical
trajectoryand vertical optical acceleration) away from their reference
states.
BP: Specifically, move yourself so the ball appears to be ascending
slowly at a constant speed and in a vertical direction. If you can do
this, the ball will pass within reach just above your head, and it won’t
hit you in the head or body if you miss it (unless your glove deflects it
downward, so angle the glove up a little). This was actually mentioned in
print first by a physicist named Chapman, if I remember the name right,
in Science, some time in the '60s I think. He didn’t know he was talking
about controlling a perception, but he was. I told Rick about this and he
used it as the starting point of his modeling.
I just Googled “chapman catch fly ball science” and came up
with
http://www.livescience.com/3445-baseball-players-catch-fly-balls.html
Chapman called his theory OAC or Optical Acceleration Cancellation,
but the way he described it was that the fielder would keep the tangent
of the vertical angle increasing at a constant rate. As a physicist, he
thought in terms of the actual vertical acceleration, which would
be proportional to the tangent of the apparent (angular) acceleration.
However, the fielder perceives the apparent acceleration, not the actual
acceleration, and keeping the apparent vertical angular acceleration at
zero works better (you don’t have to perceive the horizontal distance to
the ball accurately and multiply it by the tangent of the angle to get
the vertical acceleration). Of course keeping the angular acceleration at
zero means keeping the angular velocity constant, which is what we
actually do. My recommendation of keeping the velocity small and positive
(upward) is simply a safety precaution, though I believe Chapman also
described it that way. You will also be able to “Look the ball into
the glove” as baseball coaches put it, because the glove won’t hide
the ball as you catch it. If you keep the velocity small and downward,
the ball will hit you in the stomach if you miss the catch. What you
really don’t want to do is keep the vertical velocity at zero. If
you do that perfectly, the ball will hit you in your dominant eye when
you miss.
The author of the article in the link above missed the
control-of-perception point entirely: “First, great ballplayers will
not sprint to the exact spot on the field where they think the ball will
land and then wait for it. Rather, they usually adjust their speed to
arrive at the landing spot just as the ball arrives.” Of course they
don’t do that. The speed is simply adjusted however necessary as part of
keeping the ball slowly rising vertically as the moving fielder sees it.
It’s a very simple control system (or two of them operating at right
angles). That gets the fielder to the right spot at the right time
without having to make any predictions.
The author concludes, “So, if you’re now coaching Little Leaguers,
be patient. Their brains may still be learning the math.” This idea
of compute-and-execute is the new shibboleth we now have to fight – it
pervades neuroscience and is worse that the “inverse dynamics and
kinematics” arm-waving and stimulus-response stuff we’ve been
dealing with for decades. Of course an outfielder’s brain does no
mathematics on the way to catching a fly ball. If your average outfielder
who got an A in math could do it at all, he would probably miss the
catch. Even if you could do analytical geometry perfectly and instantly,
which a brain can’t do, you can neither perceive nor act accurately
enough to make that work.
Here’s a link to download a demo I wrote a few years ago, after Rick
started his fly ball project.
[
http://www.billpct.org/CatchBall.exe
](http://www.billpct.org/CatchBall.exe)The two structures you see are supposed to be left and right
grandstands. You’re an outfielder and you can move yourself on the field
by moving the mouse left-right or forward-backward. If you center
yourself relative to the two grandstands and move the mouse forward,
you’ll see the baselines with second base closest to center. A flyball
will be seen at first, but ignore it.
A left-click causes a fly ball (a black dot) to be batted in some
direction and with some speed. You have to move to catch it. You can’t
actually catch it, but for most trials, you can make it pass close to
you. You’ll see it getting bigger just as it gets to you. You can move a
lot faster than a real outfielder could. Just maneuver yourself to keep
the ball rising vertically (not drifting left or right) at a VERY slow
constant rate. It will come near enough to look like a black circle just
before it disappears. It’s the actual apparent size of a baseball. If you
back up a little you’ll see the ball where it landed (it doesn’t
roll).
I didn’t keep track of how the fielder moved so it could be displayed
after a catch. I guess I should do that, but the source code (Delphi) is
available if anyone else wants to do it first. Maybe I’ll use this as an
opportunity to learn more about using OpenGL, a nifty graphics system
built into most computers.
Best,
Bill P.
At 08:33 AM 4/18/2011 -0400, David Goldstein wrote:
Rick,
Stick to catching a flyball. From what you have found out, what would you tell a person who doesn't know how to catch a flyball to attend to?
David
----- Original Message ----- From: "Richard Marken" <rsmarken@GMAIL.COM>
To: <CSGNET@LISTSERV.ILLINOIS.EDU>
Sent: Monday, April 18, 2011 11:56 AM
Subject: Re: Flyball
[From Rick Marken (2011.04.18.0900)]
On Mon, Apr 18, 2011 at 5:33 AM, davidmg <davidmg@verizon.net> wrote:
Rick,
Would there be any different coaching tips you would give for someone
learning to catch a flyball based on the different models for what is
attended to?Hi David
Not really. I did (and continue to do) the 'object interception"
research as an illustration of what I think basic research on PCT
might look like. I think this research can be used to illustrate what
a controlled variable _is_, how one can go about testing hypotheses
about what variables are being controlled in a particular behavioral
situation and how to use modeling as an intrinsic part of the research
process.I don't think the specific results of the research would be useful to
a coach, mainly because it's possible that different people might
control different perceptions in these circumstances. So far it looks
like everyone does seem to control vertical optical velocity and
lateral optical angle, but some might use different variables or it
may be that the "true" controlled variables in this situation are
similar but not identical to vertical optical velocity and lateral
optical angle.What I think could be useful for coaches in general is just an
understanding that the behavior they see people performing represents
the coach's view of the side effects of control of perception. So to
teach a skill you don't show a person what observable behavior to
produce; you try to tell them what kind of perceptions to produce for
themselves. A forehand in tennis, for example, is, from the point of
view of the player, a set of mainly proprioceptive and some visual
perceptions, that are controlled. A good coach would, I believe, try
to describe what the player is supposed to try to "feel" (orientation
of the arm and wrist, the movement of the arm and wrist relative to
the body, etc) and see (the face of the racket oriented perpendicular
to the ground as it strikes the ball) in order to produce the intended
result (forehand smash going 6 inches over the net).Best
Rick
--
Richard S. Marken PhD
rsmarken@gmail.com
www.mindreadings.com
[From Fred Nickols (2011.04.18.0954 MST)]
Wayne Gretzky famously said, “I skate to where the puck is going to be, not where it has been.” Presumably, a few outfielders might say they run to where the ball will be and probably none of them would say “I control my perception of where it is.” Anyway, although pucks do sometimes go in the air, most of the time they’re on the ice so there’s little vertical movement to factor in. Has anyone done a demo of a skater intercepting a moving puck? It seems to me it ought to be simpler than a fly ball demo.
Fred Nickols
From: Control Systems Group Network (CSGnet) [mailto:CSGNET@LISTSERV.ILLINOIS.EDU] On Behalf Of Bill Powers
Sent: Monday, April 18, 2011 9:43 AM
To: CSGNET@LISTSERV.ILLINOIS.EDU
Subject: Re: Flyball
[From Bill Powers (2011.04.18.0840 MDT)]
At 08:33 AM 4/18/2011 -0400, David Goldstein wrote:
DG: Would there be any different coaching tips you would give for someone learning to catch a flyball based on the different models for what is attended to?
Rick Marken: So far, my hypothesis fits the
data best, particularly in situations where the actual trajectory of
the ball (or object to be caught, such as a Frisbee) results in
disturbances that “push” the alternative variables (optical trajectory
and vertical optical acceleration) away from their reference states.
BP: Specifically, move yourself so the ball appears to be ascending slowly at a constant speed and in a vertical direction. If you can do this, the ball will pass within reach just above your head, and it won’t hit you in the head or body if you miss it (unless your glove deflects it downward, so angle the glove up a little). This was actually mentioned in print first by a physicist named Chapman, if I remember the name right, in Science, some time in the '60s I think. He didn’t know he was talking about controlling a perception, but he was. I told Rick about this and he used it as the starting point of his modeling.
I just Googled “chapman catch fly ball science” and came up with
http://www.livescience.com/3445-baseball-players-catch-fly-balls.html
Chapman called his theory OAC or Optical Acceleration Cancellation, but the way he described it was that the fielder would keep the tangent of the vertical angle increasing at a constant rate. As a physicist, he thought in terms of the actual vertical acceleration, which would be proportional to the tangent of the apparent (angular) acceleration. However, the fielder perceives the apparent acceleration, not the actual acceleration, and keeping the apparent vertical angular acceleration at zero works better (you don’t have to perceive the horizontal distance to the ball accurately and multiply it by the tangent of the angle to get the vertical acceleration). Of course keeping the angular acceleration at zero means keeping the angular velocity constant, which is what we actually do. My recommendation of keeping the velocity small and positive (upward) is simply a safety precaution, though I believe Chapman also described it that way. You will also be able to “Look the ball into the glove” as baseball coaches put it, because the glove won’t hide the ball as you catch it. If you keep the velocity small and downward, the ball will hit you in the stomach if you miss the catch. What you really don’t want to do is keep the vertical velocity at zero. If you do that perfectly, the ball will hit you in your dominant eye when you miss.
The author of the article in the link above missed the control-of-perception point entirely: “First, great ballplayers will not sprint to the exact spot on the field where they think the ball will land and then wait for it. Rather, they usually adjust their speed to arrive at the landing spot just as the ball arrives.” Of course they don’t do that. The speed is simply adjusted however necessary as part of keeping the ball slowly rising vertically as the moving fielder sees it. It’s a very simple control system (or two of them operating at right angles). That gets the fielder to the right spot at the right time without having to make any predictions.
The author concludes, “So, if you’re now coaching Little Leaguers, be patient. Their brains may still be learning the math.” This idea of compute-and-execute is the new shibboleth we now have to fight – it pervades neuroscience and is worse that the “inverse dynamics and kinematics” arm-waving and stimulus-response stuff we’ve been dealing with for decades. Of course an outfielder’s brain does no mathematics on the way to catching a fly ball. If your average outfielder who got an A in math could do it at all, he would probably miss the catch. Even if you could do analytical geometry perfectly and instantly, which a brain can’t do, you can neither perceive nor act accurately enough to make that work.
Here’s a link to download a demo I wrote a few years ago, after Rick started his fly ball project.
[http://www.billpct.org/CatchBall.exe
](http://www.billpct.org/CatchBall.exe)The two structures you see are supposed to be left and right grandstands. You’re an outfielder and you can move yourself on the field by moving the mouse left-right or forward-backward. If you center yourself relative to the two grandstands and move the mouse forward, you’ll see the baselines with second base closest to center. A flyball will be seen at first, but ignore it.
A left-click causes a fly ball (a black dot) to be batted in some direction and with some speed. You have to move to catch it. You can’t actually catch it, but for most trials, you can make it pass close to you. You’ll see it getting bigger just as it gets to you. You can move a lot faster than a real outfielder could. Just maneuver yourself to keep the ball rising vertically (not drifting left or right) at a VERY slow constant rate. It will come near enough to look like a black circle just before it disappears. It’s the actual apparent size of a baseball. If you back up a little you’ll see the ball where it landed (it doesn’t roll).
I didn’t keep track of how the fielder moved so it could be displayed after a catch. I guess I should do that, but the source code (Delphi) is available if anyone else wants to do it first. Maybe I’ll use this as an opportunity to learn more about using OpenGL, a nifty graphics system built into most computers.
Best,
Bill P.
[From Bill Powers(2011.04.18.1110 MDT)]
Fred Nickols (2011.04.18.0954 MST) –
Wayne Gretzky famously said, I
skate to where the puck is going to be, not where it has been.
Presumably, a few outfielders might say they run to where the ball will
be and probably none of them would say I control my perception of where
it is. Anyway, although pucks do sometimes go in the air, most of
the time theyre on the ice so theres little vertical movement to factor
in. Has anyone done a demo of a skater intercepting a moving
puck? It seems to me it ought to be simpler than a fly ball
demo.
I sent a link in my previous post to an article in which it was mentioned
that skilled baseball players actually do poorly at estimating where a
ball is going to drop – even when they devoutly believe, and say, that
they run to where the ball is going to be.
Even the greatest can have the wrong explanation for what they do.
Gretzky was describing the effect of what he did but that, I guarantee,
is not what he did. The simplest way to “skate to where the puck is
going to be” is to skate so that the puck remains in a constant
direction from your direction of travel. You change your direction of
travel and/or your speed until the direction to the puck stops changing.
That will get you to where the puck is going to be without calculating
where it’s going to be.
This is also how the conning officer of an oil tanker can tell whether
the tanker is on a collision course with another ship. In his case you do
NOT want the other ship to stay at a constant bearing. As I have
mentioned several times on CSGnet, this is taught in the Navy as the way
to avoid collisions. If you want to have a collision (with a puck) this
is the most reliable way to do it.
http://en.wikipedia.org/wiki/Proportional_navigation
“The basis of proportional navigation was first discovered at sea,
and was used by navigators on ships to avoid collisions. Commonly
referred to as
Constant Bearing Decreasing Range (CBDR), the concept continues to
prove very useful for conning officers (the person in control of
navigating the vessel at any point in time) because CBDR will result in a
collision or near miss if action is not taken by one of the two vessels
involved. Simply altering course until a change in bearing (obtained by
compass siting) occurs, will provide some assurance of avoidance of
collision. Obviously not foolproof, the conning officer of the vessel
having made the course change, must continually monitor bearing lest the
other vessel does the same. Significant course change, rather than a
modest alteration, is prudent.
International Regulations for Preventing Collisions at Sea dictate
which vessel must give way but they, of course, provide no guarantee that
action will be taken by that vessel.”
This article also shows how a Sidewinder missile uses this principle to
hit its target.
Best,
Bill P.
[Martin Taylor 2011.04.18.13.56]
[From Bill Powers(2011.04.18.1110 MDT)]
Fred Nickols (2011.04.18.0954 MST) --
Wayne Gretzky famously said, �I skate to where the puck is going to be, not where it has been.� ...
I sent a link in my previous post to an article in which it was mentioned that skilled baseball players actually do poorly at estimating where a ball is going to drop -- even when they devoutly believe, and say, that they run to where the ball is going to be.
Even the greatest can have the wrong explanation for what they do. Gretzky was describing the effect of what he did but that, I guarantee, is not what he did. The simplest way to "skate to where the puck is going to be" is to skate so that the puck remains in a constant direction from your direction of travel.
My understand of Gretzky's comment has always been that he understood the play, not the trajectory of the puck. He judged where his own and the opposition players would try to move the puck, so he could be where whoever would be controlling the puck would take it, if it would be useful for him to be there.
On the flyball topic, in my cricketing career I usually played close to the bat, in a position where almost none of my catches had the ball trajectory going above me, and the ball came fast with little gravitational drop. Many of them were caught one-handed at full stretch just before the ball hit the ground to my left or right, sometimes after a leap in that direction. I think a different analysis of the controlled perception is need for that condition. Likewise, for a fly ball in the cricket outfield, one is never taught to catch the ball overhead unless it is unavoidable. One tries to catch it somewhere near chest or waist high in cupped hands, depending on whether the dropping trajectory is more vertical or more horizontal when the ball reaches you. Remember that cricketers do not use gloves, and the ball has the same dimensions and weight as a baseball.
Martin
Yes here's one learn Geometrodynamics.
Rick,
Would there be any different coaching tips you would give for someone
learning to catch a flyball based on the different models for what is
attended to?
David
----- Original Message -----
From: "Richard Marken" <rsmarken@GMAIL.COM>
To: <CSGNET@LISTSERV.ILLINOIS.EDU>
Sent: Monday, April 18, 2011 12:15 AM
Subject: Re: Flyball
[From Rick Marken (2011.04.17.2115)]
Gavin Ritz (2011.04.18.11.10NZT)
GR: What exactly is the catcher controlling?
There are several hypotheses regarding what a real fielder (or
catcher) is controlling when they move to catch a fly ball. One
hypothesis is that the fielder is controlling the optical trajectory
of the ball, an trying to keep it linear (this is called the Linear
Optical Trajectory hypothesis). Another hypothesis is that the
controlled variable is vertical optical acceleration and lateral
angle. My hypothesis is that the controlled variable is vertical
optical velocity and lateral angle. So far, my hypothesis fits the
data best, particularly in situations where the actual trajectory of
the ball (or object to be caught, such as a Frisbee) results in
disturbances that "push" the alternative variables (optical trajectory
and vertical optical acceleration) away from their reference states.
I don't want to give you the answers Rick because you don't Trust my
answers.
I don't trust anyone's answers including my own. That's why I do
research to test my "answers". Trust but verify;-)
Answer this then we will be moving to get on the same page.
OK, I answered it. Are we on the same page now?
Let me suggest a wonderful book by John Wheeler called "Journey into
Space-Time"
Thanks.
Best
Rick
--
Richard S. Marken PhD
rsmarken@gmail.com
www.mindreadings.com
[From Rick Marken (2011.04.18.1330)]
Rick,
Stick to catching a flyball. From what you have found out, what would you
tell a person who doesn't know how to catch a flyball to attend to?
Bill actually answered this: "move yourself so the ball appears to be
ascending slowly at a constant speed and in a vertical direction". The
reason I didn't think this was practical knowledge for catching is
because my kids learned to catch before they were particularly
articulate ("ascending" and "vertical" would probably have given them
problems at 3 year of age). So they learned rather quickly by
reorganizing their own control systems based on trying.
Bill was (dare I say it) wrong about one thing. He said: " keeping the
apparent vertical angular acceleration at zero works better" which
implies that vertical angular acceleration is (or could be) one of the
variables controlled when intercepting a fly ball. In fact, angular
acceleration will not work reliably as the controlled variable when
it's kept at or slightly greater than 0 because it is crucial that
the velocity be kept close to zero but positive. In my models, when
acceleration is controlled (with a reference of 0 or slightly >0) the
velocity is often way too high. That's because you can keep
acceleration at zero for any non-zero velocity (which is familiar to
you from driving a car; you can cruise -- zero acceleration -- at 60,
70, or 20 mph -- velocity). So my modeling shows that it must be
vertical optical velocity that is controlled and it must be controlled
just slightly above zero.
As for intercepting pucks, there have been studies of people catching
ground balls; I haven't analyzed that data yet using my model but
based on what I've see it looks like the same controlled variables are
involved in this case as well. So far my model has been able to
account for intercepting fly balls, Frisbees and toy helicopters (the
latter two having quite unpredictable trajectories so prediction won't
work for sure). I think control of vertical optical velocity and
lateral horizontal angle may be the variables involved in all
"intercepting" type behaviors.
Best regards
Rick
On Mon, Apr 18, 2011 at 9:46 AM, davidmg <davidmg@verizon.net> wrote:
--
Richard S. Marken PhD
rsmarken@gmail.com
www.mindreadings.com
(Gavin Ritz 2011.04.19.8.47NZT)
[From Rick Marken
(2011.04.18.1330)]
Rick,
Stick to catching a flyball. From what you have
found out, what would you
tell a person who doesn’t know how to catch a
flyball to attend to?
Bill actually answered
this: "move yourself so the ball appears to be
ascending slowly at a constant speed and in a vertical
direction". The
reason I didn’t think this was practical knowledge for
catching is
because my kids learned to catch before they were
particularly
articulate (“ascending” and
“vertical” would probably have given them
problems at 3 year of age). So they learned
rather quickly by
reorganizing their own control systems based on
trying.
That’s because at
the energetic level they are probably mirroring the momenergy internally and trying
to match that externally.
That’s why this
question is being posed “is the human brain a space-time
energy transducer”
Of-course at the
mechanical level just like Newton’s
laws hold good so would all your flyball assumptions. But that is not what this
discussion is about.
Anyways I’m a off
to work.
Regards
Gavin
On Mon, Apr 18, 2011 at 9:46 AM, davidmg davidmg@verizon.net wrote:
[From Rick Marken (2011.04.18.1620)]
Gavin Ritz (2011.04.19.8.47NZT)
> Rick Marken (2011.04.18.1330)]
RM: Bill actually answered this: "move yourself so the ball appears to be
ascending slowly at a constant speed and in a vertical direction".GR: That�s because at the energetic level they are probably mirroring the
momenergy internally and trying to match that externally.
OK, that's your theory. How do we test it?
Best
Rick
--
Richard S. Marken PhD
rsmarken@gmail.com
www.mindreadings.com
(Gavin Ritz 2011.19.12.41NZT
[From Rick Marken
(2011.04.18.1620)]
Gavin Ritz (2011.04.19.8.47NZT)
Rick Marken
(2011.04.18.1330)]
RM: Bill actually answered this: "move yourself so the ball appears to
be
ascending slowly at a constant speed and in a
vertical direction".
GR: That’s because at the energetic level
they are probably mirroring the
momenergy internally and trying to match that
externally.
OK, that’s your theory.
It’s not a very
good theory, actually it’s a declarative statement. It sounded good.
How do we test it?
Well at the mechanical level,
I don’t have to you have already done the job.
At the energetic level I haven’t
the foggiest idea.
Regards
Gavin
[From Bill Powers (2011.04.19.0900 MDT)]
Martin Taylor 2011.04.18.13.56 --
MMT: My understand of Gretzky's comment has always been that he understood the play, not the trajectory of the puck. He judged where his own and the opposition players would try to move the puck, so he could be where whoever would be controlling the puck would take it, if it would be useful for him to be there.
BP: I may have misunderstood the reference to what he said. In the article I linked to, on the other hand, it was said that well-known baseball players said they thought they ran to where the ball was going to be, despite the finding that they were not good enough at predicting where the ball would be to catch it very often that way. Rick's models, on the other hand, show how easy it is to be at the right place at the right time without controlling specifically for that situation.
Ask any bicycle rider to describe the first move to make in order to transition from riding in a straight line to riding in a left turn. Very few of them will give the right answer, which is "Turn the front wheel to the right." Most will say they lean to the left, which is the consequence of turning the front wheel to the right. I don't know what Lance Armstrong would say, but just being famous is no guarantee that a person will notice details of actual behavior. Most people pay attention to the outcomes of behavior.
For example, when I say "turn the front wheel to the right," I am talking about a consequence of pulling on the right handlebar and/or pushing on the left handlebar, which is a consequence of tensing certain muscles. We don't normally attend very closely to the details of our own behavior.
MMT: On the flyball topic, in my cricketing career I usually played close to the bat, in a position where almost none of my catches had the ball trajectory going above me, and the ball came fast with little gravitational drop. Many of them were caught one-handed at full stretch just before the ball hit the ground to my left or right, sometimes after a leap in that direction.
BP: Yes. Even when catching a flyball, what happens at the very end can't be described in the same way as getting in the right position for the catch. I don't have any clever way to handle the end-game here.
MMT: I think a different analysis of the controlled perception is need for that condition. Likewise, for a fly ball in the cricket outfield, one is never taught to catch the ball overhead unless it is unavoidable. One tries to catch it somewhere near chest or waist high in cupped hands, depending on whether the dropping trajectory is more vertical or more horizontal when the ball reaches you. Remember that cricketers do not use gloves, and the ball has the same dimensions and weight as a baseball.
BP: In American football, catching overhead is considered less reliable than catching at chest or belly level. That's probably because missing the catch is less costly when the ball hits your body instead of sailing on past you where the wrong person might catch it. In baseball it seems to be standard practice to back up catches with the body -- "blocking" -- so the ball can be recovered quickly if missed. Ouch. I just recommended the overhead catch for safety, when teaching beginners (as David Goldstein wanted to do).
Best,
Bill P.