Saturday, August 25, 2007

The heuristic of the successful catcher

At cricket, back in my school days, I used to be a good fielder. In fact, I don’t remember to have dropped a single catch in my entire career. No, that’s not true. In one of the matches, running all the way from first slip, I failed to get my fingers on to a ball that was just crossing the fence over long on.

Anyway, the secret of my amazing skills as a catcher was that I always carried my geometry box with me, to the playground.

Gerd Gigerenzer, explains my methods, in his book, “Gut Feelings”.

Computing the trajectory of a ball is not a simple feat. Theoretically, balls have parabolic trajectories. In order to select the right parabola, the player’s brains would have to estimate the ball’s initial distance, initial velocity and projection angle. Yet in the real world, balls, affected by air resistance, wind and spin, do not fly in parabolas. Thus, the brain would further need to estimate, among other things, the speed and direction of the wind at each point of the ball’s flight in order to compute the resulting path and the point where the ball will land. All this would have to be completed within a few seconds- the time a ball is in the air….. Clearly, this is too complex a process and something else is at work.

Is there a simple rule of thumb to catch a ball? Studies have shown that experienced players use what is called the ‘gaze heuristic’ which works in situations where the ball is already high up in the air. “Fix your gaze on the ball, start running and adjust your running speed so that the angle of gaze remains constant.” The angle of gaze is the angle between the eye and the ball, relative to the ground.

Thus, good fielders, unconsciously rely on a simple rule of thumb that dictates the speed at which a player runs. Note that the player using this heuristic is not able to compute the point at which the ball will land. Yet the heuristic leads the player to the landing point.


What Gigerenzer does not mention, of course, is my name, but cleverly couches it in expressions such as ‘experienced players’; that’s because I did not give him permission to use it, till I broke the story myself in my blog. Another thing he does not mention, probably because he forgot to, is that , as I fixed my gaze on the ball and started running, I used to quickly open my geometry box, pull out the protractor and keep measuring the angle of gaze and adjust my speed in such a way as to keep the angle constant.

Yes, that was my technique. It’s out in the open now.

There’s just that solitary instance to be explained. Why did I drop that catch at long-on? What happened was that, as I ran from my position at first slip, I tripped over the fielder standing at mid-wicket and dropped my protractor on the ground. I picked it up in a second and started running again, but the angle of gaze had changed by a couple of degrees, rendering the heuristic unworkable.

Now, you know everything..

4 comments:

chaitra said...

Ha ha! Every time I tell myself, "he can't probably write something better than this", and you prove me wrong, each and every time! You're just too hilarious!

Raj said...

chaitra, every time I hear you tell yourself that, I try harder to prove you wrong.

Toxic Survivor said...

I'm thankful for your boasting, as I've used your system to create a sporting equipment empire! My Raj-a-Matic CatcherCap will be on retail shelves from Chicago to Chenai on Monday; with ballistic nylon cap and swivel-attached carbon composite protractor it will revolutionize cricket and baseball. Since the hat holds the protractor unaided, the catcher has an extra hand free. Now he can actually catch two balls at once! The games will be changed forever.

Raj said...

toxic survivor, I am so glad that somebody is commercialising my idea. Do remember the royalty, though.