Modeling the Tennis Context
Do as I say, not as I do!
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In setting up my target-shooting games (which involve both study or practice and challenge shots), I ignored the players, linesmen, spectators, birds, sun, wind, etc., things that make up the real tennis context. I also put the bio-physical aspects of the player on the back burner (aspects like the ability to hold and swing a racket). I confined my attention just to physical properties of the court and adopted Newton’s mechanics of motion of the ball. This defined the objective court.
Relativity theory may have displaced Newton's theory for representing the universe, but the classical view still dominates in everyday regions. For court distances, the speed of light might just as well be infinite, as Newton hypothesized, and the nature of space might just as well be flat, as he argued. So I stick with Newtonian physics as the best available investigative tool. (For the really small stuff, you have to depend on Quantum Mechanics.)
For the perceiver’s chunk of the objective environment (the subjective side), I've taken as given the empirical facts of the visual and motor system that defines the organism that perceives the objective stuff of the court.
After simplifying the objective tennis world, I simplified the equations of the player’s subjective world (i.e., the objective world of the court and the athlete himself as viewed by the athlete himself). I ignored almost all of the player’s personal attributes, leaving just those directly related to tracking and reacting to the moving ball by intercepting and hitting it. In the thesis phase of the project I allowed for various strategies for intercepting the ball. The player was also able to perceive, i.e., to visually measure (though not perfectly) the distance to the ball and its speed.
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Tracking and intercepting a ball is a complex process involving interaction between the athlete and his/her environment. The player must perceive the moving ball, estimate what it's doing, determine an intercept point, and exercise muscle control for the intercept. This involves perceptual mechanisms (the special way we see) and plans that interpret the motion and lead to a judgment of the remaining distance to the projected intercept point and the time remaining to get there. Faulty judgment is immediately reflected in the difference between what is expected and what is perceived. The feedback alters the player's running and tracking tactics. Meantime, tracking must be continued and the body and racket readied to make a return shot. This requires serious concentration and an effective system of mental representations (concepts, theories, plans). That, at any rate, is the way it seems to work.
Unfortunately, we don’t any of us really know how we actually track a tennis ball, which can be fast-moving. Nor, for that matter, do we know how we perceive our worlds. The odd thing is, tracking is so easy, even children and pets can be successful at it, and that says a lot for the potency of the brain. Granted, the ball motion is typically slow. But even so, there is still blurring, which hints at the limitations of visual perception as a n investigative tool.
The real art of tracking is in the refinement of the skill, to be able to intercept and return hard shots repeatedly. To reach this ideal, careful analysis of trajectories and controlled court practice are essential. You want to program your intercept trajectory to be able to intercept any oncoming ball in a timely manner and swing your racket freely and properly at it for a successful return shot. Not easy.
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What we experience depends on our makeup and the way we’ve learned to use our various neural subsystems. The experience must vary from one person to the next, because our histories are different and our sensors are qualitatively different one to another. And as individuals differ, so too their cells differ, one person to the other. We are each very unique. (In the extreme, for example, a case of visual blindness leaves one only with a void for the visual component of our subjective view.
Because of the many detailed structural differences between us, there can be significant differences between our individual experiences (differences in the way we experiment). Faulty sensors alone create variations. Also, we can, and we do, classify (conceptualize) our percepts differently (both objects and events). For instance, we might not agree as to how particular tennis rackets should be classified. The differences can show up in the way we learn skills and in the way we behave generally.
Furthermore, what we experience could be quite different from what occurs objectively in that world, including what's happening to us, personally. In other words, because of the quality of our biological mechanisms we can at times be seriously mistaken in seeing what has happened, including what might just have occurred at the tennis court -- disputes arise all too often. I see them as failed experiments.
Despite the possible perceptual errors and the fact that we can only see ourselves in a personally constructed world, we can still learn about the objective world. Learning actually changes the way we see the world, the way we put it together. What we take to be objective at one time might not be understood as such later; we do the best we can with what we know. (As an example of learned perceptual differences, you might think about the changes that can occur in our reading of a foreign language as we learn it. Learned words and phrases seem to spring up out of gibberish. A sentence in Russian, for instance, can make more sense and take on a new quality as it becomes more familiar to us.) So too the path of a tennis ball can become more significant with increased trials. It makes sense that we can learn to project the path differently, more effectively. Proper learning should improve our percepts, bring us closer to what is truly there.
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