Tennis Serves Faster Than the Speed of Sight
Tennis superstars can return serves of over 120 mph. But are they aware of what they are doing?
In 2011 Croatian tennis player Ivo Karlovic set a new world record with a serving speed of 156 mph, beating the previous record holder, Andy Roddick, by 1 mph. Andy Murray and Jo-Wilfried Tsonga have both been known to serve at speeds of approximately 145 mph. The fastest serving woman has reached 130 mph. Players of both sexes regularly serve at speeds of over 120 mph.
As you watch those serves sizzle across the net, you may doubt that the opponent can have sufficient time to register the position of the ball, gauge the angle and force required to return it, and react accordingly. Yet, as often as not, the serve is returned, and with devastating accuracy.
The explanation of this seeming impossibility is believed to lie in the existence of two separate visual systems two within the brain. The slower of the two, known as the ventral stream, is involved in identifying objects. It gives rise to the subjective experience of 'seeing' and contributes to the formation of vision-related memories. The second system, the dorsal stream, is faster and, although no visual experience is associated with it, its circuitry enables a sequence of visuomotor activities such that the organism - in this case the tennis player - makes the appropriate actions without any conscious act of will being involved.
In most people, both systems are operational and, in fact, conscious perception often plays an active part in determining motor responses to visual stimuli. Tennis players are usually aware of seeing even the fastest serves, the only difference being that in this case, this awareness comes too late to be able to feed back in to control the movement of returning the ball. The same is true of many other practised series of movements, particularly in sport.
Blindsight
Evidence of the subcortical dorsal route is provided by people who have damage to the primary visual cortex, the part of the brain associated with visual awareness. When this occurs the ventral route is incapacitated. It appears, however, that such people, who claim in all sincerity that they are unable to see, can, in fact, respond to visual stimuli. The condition, known as blindsight - a term coined by neurologist Lawrence Weiskranz - has been demonstrated in a variety of experiments in which blindseers, when prompted to do so, are found to able to point to objects, discriminate facial expressions, navigate obstacles, and so on with a high rate of success.
So are the top tennis players mere robots, with visuomotor systems operating as mechanically as the reflex arcs triggered when a doctor taps a patella? It appears not. To reach the level of skill required to return those serves, players must spend countless hours practising, first of all with intense conscious effort and attention. Only when the movements become automatic and fine-tuned can the ventral system take a back seat. When that point is reached, conscious attention can even get in the way.
If you can touch-type think of the speed and ease with which you do so. Then try to type while trying to remember where the various letters are on the keyboard before hitting each key. I guarantee that it will take you much longer, and possibly result in mistakes. This is how it is with all automatised behaviour.
Published online, Suite101
As you watch those serves sizzle across the net, you may doubt that the opponent can have sufficient time to register the position of the ball, gauge the angle and force required to return it, and react accordingly. Yet, as often as not, the serve is returned, and with devastating accuracy.
The explanation of this seeming impossibility is believed to lie in the existence of two separate visual systems two within the brain. The slower of the two, known as the ventral stream, is involved in identifying objects. It gives rise to the subjective experience of 'seeing' and contributes to the formation of vision-related memories. The second system, the dorsal stream, is faster and, although no visual experience is associated with it, its circuitry enables a sequence of visuomotor activities such that the organism - in this case the tennis player - makes the appropriate actions without any conscious act of will being involved.
In most people, both systems are operational and, in fact, conscious perception often plays an active part in determining motor responses to visual stimuli. Tennis players are usually aware of seeing even the fastest serves, the only difference being that in this case, this awareness comes too late to be able to feed back in to control the movement of returning the ball. The same is true of many other practised series of movements, particularly in sport.
Blindsight
Evidence of the subcortical dorsal route is provided by people who have damage to the primary visual cortex, the part of the brain associated with visual awareness. When this occurs the ventral route is incapacitated. It appears, however, that such people, who claim in all sincerity that they are unable to see, can, in fact, respond to visual stimuli. The condition, known as blindsight - a term coined by neurologist Lawrence Weiskranz - has been demonstrated in a variety of experiments in which blindseers, when prompted to do so, are found to able to point to objects, discriminate facial expressions, navigate obstacles, and so on with a high rate of success.
So are the top tennis players mere robots, with visuomotor systems operating as mechanically as the reflex arcs triggered when a doctor taps a patella? It appears not. To reach the level of skill required to return those serves, players must spend countless hours practising, first of all with intense conscious effort and attention. Only when the movements become automatic and fine-tuned can the ventral system take a back seat. When that point is reached, conscious attention can even get in the way.
If you can touch-type think of the speed and ease with which you do so. Then try to type while trying to remember where the various letters are on the keyboard before hitting each key. I guarantee that it will take you much longer, and possibly result in mistakes. This is how it is with all automatised behaviour.
Published online, Suite101