Balls Out

An article in Newsweek explains how line judges can make those crazy-making line calls that can ruin tennis matches -- "Out!"

Memo to tennis players: because of the way the human visual system works, referees are more likely to call “out” a ball that actually lands in, rather than call “in” a ball that in fact lands outside the line. Now that professional players are permitted to challenge calls, therefore, they would do well to focus on balls that are called “out,” since they are more likely to be wrong.

So concludes a neat little study published online today in Current Biology. Scientists led by David Whitney of the University of California, Davis, started from the fact that the human visual system consistently misperceives moving objects as shifted in the direction of their motion, making them appear to be farther along their path than they are.

When I play, I'm pretty generous with calling balls in. If it looks even a few inches from the line. I usually just call it in. Looks like calling it in is a good call. Karma meets cognitive science.

Oh, and the picture of Marat Safin above is just because.