Storytelling Science

Sehwag's Brain

Amitabha Mukerjee


Shoaib Akhtar's ball, all 100 mph of it, is less than half a second from crunching into your ribcage. If you are like me, your top priority is having intact bones after the encounter. And yet Virendra Sehwag goes out there, throws all batting rules to the four winds, and manages to score three hundred runs. Obviously, somewhere, something is wired very differently in his brain!

Consider the magnitude of the task. Your eye can see well only for a small region (abt a 50-paisa coin at arms length). This foveal region is held steady for about 1/3d of a second (called a saccade) before being whipped around amazingly fast (700deg/sec) to some other point of interest. This is what your eyes are doing even as you read t h e s e w o r d s, but you are so used to it, it's hard to catch yourself doing this.

Change Blindness

What most of us don't realize is that we don't "look" at things even when we are looking straight at them. Say you go into Nirula's, and are ordering food from the lit-up menu. Suddenly the man at the cash register drops a pencil and goes beneath the counter to fetch it. Unknown to you, this is actually a psychology experiment, and out pops an altogether different man! His face is different, he has a moustache, he is a bit taller. Would you notice? This phenomenon is called Change Blindness, and overwhelmingly, people don't see it!

This happens because our mind can only calculate so much. To survive, we must pay "attention" only to that which is likely to be most crucial, and If someone's face is not likely to change, we don't refresh it.

Fixating the Eye

So what is crucial about Shoaib's ball? What you and I do, and many coaches recommend, is "to keep your eye on the ball". But this is very difficult because of the ball's speed and we get only very rough estimates of its motion. If we could see the ball with the eye at rest, we could get some really precise data.

Where would you look while Shoaib's ball is hurtling towards your ribcage
? [Image: Mooshir Vahanvati]

But each fixation is about 300 milliseconds, and in the half second that Shoaib's ball will take, you can have at most one saccade. So how does Sehwag's brain cope? Recently some British neuroscientists studied cricketers' gaze by using "eye-trackers". Here is what they found: Until the point of delivery, an expert batsman like Sehwag fixes his gaze on the bowler's delivery, from which he guesses the bounce point. He makes no attempt at all to "keep his eyes on the ball". His gaze races ahead and locks onto the bounce point about 150 milliseconds before the ball gets there. Where it bounces, and how soon, tells him the two things he needs to know when will the ball reach the bat, and how high will it be then. You can work these out with class nine physics, but Sehwag's brain learns this and stores it in its circuits, (which is a lot faster than algebra). Knowing these, he can swing his bat with the millisecond precision needed to hit those fabulous sixers. . .

So now you can see why this plan is really the "best". Given you have just this one saccade, this is the best possible way to use it. Sehwag's brain has learned it from experience. Next time you see him batting, think of his brain, and let its workings illuminate your own personal science . . . and that of a child near you.

Amitabha Mukerjee ( theorizes about cricket and brains at the Computer Science Dept, IIT