Working in Movement

I recently had the fun opportunity to play ball with my three-year old grandson. His throws are pretty wild at this stage, and catches happen fairly infrequently, but he's learning rapidly. Though it seems a simple thing, catching a ball involves a lot when you really think about it. You need to gauge where the ball is coming from, where it's going and then get yourself and your hands into a position to snag the ball as it descends. And all this without benefit of computers calculating angles and trajectories. Learning how to do it takes time, and some people master it better than others. How do they do it?

Not surprisingly, it involves keeping your eye on the ball, but in a special way. A thrown or batted ball changes trajectory and velocity as it travels through the air. According to a recent study, successful fielders position themselves relative to the ball so that the image of the ball appears to have a constant velocity and trajectory. In other words, they run fast and keep their eye on the ball until they intercept it. There is even a name for this strategy: the Linear Optical Trajectory or LOT. Researchers came up with the LOT idea after watching tapes of small video cameras worn by good baseball players.

Now it turns out that LOT practices aren't restricted to baseball players or even to humans. Dogs Catching Frisbees briefly describes research that strapped video cameras to the heads of two dogs catching frisbees. (I guess dogs don't make good outfielders.) Researchers threw the frisbees from a variety of angles and at different velocities. Being good dogs, the dogs caught them on the fly. Researchers analyzed the tapes and discovered the dogs used the LOT idea for positioning themselves to catch the flying discs.

And maybe the dogs didn't have to go through a long apprenticeship to learn how to catch the frisbees. In How Dogs Navigate To Catch Frisbees, one observer suggested the dogs' natural ability.

Dogs seem to have an instinctive ability to catch fast-moving objects, even as puppies, Marken added, whereas humans need a bit more training. "It's what evolution has done for dogs, and less so with humans," he said. "People have to learn it more."