[Martin Taylor 2012.11.28.22.50]
From Bill Powers (2012.11.27.1350 MST)]
Fred Nickols (2012.11.27.0942 AZ) --
[Fred Nickols] I think it's important to note that I am NOT predicting
where the ball will land or even where it is going. I am predicting the
likelihood that I can intercept it (based on my perception of the relative
movement between me and the ball). If it becomes clear to me that I can't
catch it I will likely change course and head toward where I DO predict the
ball is headed or will go (and I have often been wrong and surprised on that
score, especially when the ball takes an odd bounce).When you look at the ball and see that it is moving neither up, down, left, or right, but remains at a fixed angle in the sky, and when you see its image is getting larger, I think you will judge that you are going to intercept it. If it moves upward, you have to move away from it faster to bring it downward again; if it moves downward, toward it by moving a little slower away, or faster toward it. If it moves left, you move right. If right, you move left.
Something doesn't seem right about this, at least in the up-down aspect. If you are in the outfield and a ball is hit that might possibly be a potential catch, it moves upward from the bat. This is true whether the ball will land far in front of you or well behind you. Many fielders, at least in amateur cricket, run in toward the bat when the trajectory will actually pass over where they were initially standing (I missed a hat-trick -- a very rare occurrence in cricket -- in an international match because a fielder did this when he could have caught the ball if he had stood still). If they did as you propose, the universal tendency would be to move away from the bat. That is so when the ball trajectory's trace on the ground goes straight through you. It's much easier to know whether to move forward or back when you also will have to move left or right.
Later in the ball's flight, what you suggest may actually be what people do, but from long experience, the hardest thing is initially to decide whether to move back, forward, or stand still. In support of your proposal, it is much easier to catch a ball against a backdrop of fluffy, differentiated clouds than against a clear blue sky if the trajectory is so high that one cannot reference the ball's vertical angle to the ground detail.
I'm talking subjective experience here, not theory. And as we know, what one actually does may not be what one believes one does. Nevertheless, from both experience and theory, the initial movement of the ball off the bat is upward, and when fielders in cricket do make a mistake it is almost always to run inward when they shouldn't.
Martin