Umpires can’t help but call it out


Originally published on: 26/02/10 15:01

Whod be a sporting official? Boxing referees have to put their bodies on the line to ensure two professional fighters keep it legal. Footballs assistant referees have to look in about eight different directions simultaneously to judge a player offside. Even track and field isnt safe.

And now, scientists have proved that tennis umpires are wired to see the ball land out more often than in.

Apparently, its not just umpires. The problem involves a 100 millisecond-lag between the moment an object appears on the retina, the part of the eye that translates light into images, and when our brains spot that object.

Pros should challenge more often when the ball is called out than in

Because the brain is constantly playing catch-up with visual reality, all of us struggle to follow the trajectory of a fast-moving projectile say, a tennis ball so our brains try to fudge the results, tricking the eye into believing a ball travels that little bit further than we thought.

David Whitney, a vision scientist at the University of California, Davis, explains. “Its a consequence of human visual processing – a visual illusion caused by a mechanism that allows the system to localise a moving object.”

Whitneys study took 4,457 randomly selected points from the 2007 Wimbledon Championships, identifying 83 wrong calls. Of those 83 misjudgements, 70 involved line judges and umpires calling the ball out when in actuality it had landed in.

This year, with the advent of HawkEye challenges, Whitneys team found the same bias 69% of challenged calls judged out by line officials were actually in.

So, other than stamping our feet John-McEnroe-style about the shortcomings of the human body, how can we use the information to our advantage? Well, for the top pros, the advice is to use HawkEye challenges more strategically they should challenge more often when the ball is called out than in, Whitney says.

For the rest of us, our only hope is to dispute calls on sound scientific theory, so commit the following to memory:

Our visual system takes an image and shifts it forward and allows us to perceive it in a more physically accurate position so we can live in the present. That works great for continuously moving systems, but if something changes abruptly, there can be mistakes; the visual system has a hard time with that abrupt change.

What? Were off for a cup of tea and a lie down.


Tim Farthing, Tennishead Editorial Director & Owner, has been a huge tennis fan his whole life. He's a tennis journalist and entrepreneur as well as playing tennis to a national standard. He also helps manage his local club and volunteers for his local tennis organisation. He's a specialist in content about the administration of professional tennis and tennis coaching for all levels.