readings> anticipation in sports
Benjamin Libet's famous finding that a state of consciousness takes about half a second to form - that's how long it takes the brain to complete all the processing - poses a problem for sports enthusiasts. How does anyone ever hit a ball? Anticipation is the answer - and anticipation is critical to the understanding of consciousness itself.
It is easy to see what makes a Gooch or a Borg a great champion as they turn towards the oncoming ball, their faces dark with concentration. But the McEnroes and Gowers of this world seem somehow different. While lesser mortals grind out victories with patient shot-making, eliminating risks and playing the percentages, the truly gifted seem to conjure with time. They bring an unhurried genius to their game that allows them to play shots which sometimes surprise even themselves for sheer audacity.
Or at least this is how it seems to the spectator in the stands. But is there anything in the common belief that some players are blessed with infinite time? That some genetic advantage allows a few lucky individuals to react as if the rest of the world were moving in slow motion?
Dr Bruce Abernethy, a sports psychologist at the University of Queensland in Australia, believes there must be: "You would think there would have to be something innate in the make-up of a person like a McEnroe because a lot of the population could practice as much as he did, yet never reach his level of performance. But it's not easy to say what it is that makes the difference - you would be talking about doing something like twin studies to find out. Also, it's not likely to be any one simple answer but a mixture of many factors," he says.
While sports psychologists may not have a ready explanation for sporting genius, they are beginning to turn up a few clues - and also a few surprises. One surprise has been that raw reaction times do not appear to be the answer. The simplest assumption would be that fluent performers have more time to react because their nervous systems are literally quicker. Yet when elite athletes have been tested in standard reaction time tests - such as having to hit a switch as soon as it lights up - they are not noticeably faster than average.
"There is surprisingly little difference between top class sportsmen and good, fit ordinary people. In laboratory tests of reactions using unskilled tasks, most people show much the same reaction time of about 200 milliseconds [a fifth of a second]. So top class athletes don't appear to be tapping into some generalised superiority," says Dr Peter McLeod of Oxford University's Department of Experimental Psychology.
Even more surprising for those expecting an explanation in terms of raw speed of thought, other research has shown that it takes nearly half a second for our minds to become properly conscious of fast-moving events. It is known from EEGs and other measurements of the brain's electrical activity that it takes only about 20 milliseconds for nerve traffic to travel the distance between the sense organs and the brain. However reaction time tests show that it takes a minimum of 100 milliseconds before the brain can produce even the simplest reflexive action and nearer 200 milliseconds to make the more complex judgement involved in hitting a light switch. But research by University of California physiologist, Dr Benjamin Libet, suggests that becoming consciously aware of an event takes even longer (see below). His experiments show that it takes between 400 and 500 milliseconds for the brain to complete all the filtering and recognition processes needed to produce a settled field of awareness.
What this means is that consciousness lags behind reality by up to half a second and so any rapid reactions shown by athletes must be achieved by sub-conscious processing. Given that the time window in which a cricket or tennis player must make contact with a fast-moving ball is about five milliseconds - any sooner or later with the swing and the ball will be mishit - the mystery becomes not that some people are so skillful, but that anyone ever manages to strike a ball at all.
To investigate where the advantage of elite performers lies, sports psychologists begin by making a distinction between input and output, between perceptual and motor processes. It is assumed that the gifted either manage to make quicker sense of what they are seeing, or else they are able to unleash a more reliable and smoothly co-ordinated response - or, of course, both.
As said, it is known that top flight performers are not significantly faster than the average in their raw reaction times - scores vary by about 25 milliseconds and there is no significant clustering of the skilled at the top of this range. But equally there is plenty of evidence that players do use anticipation to quicken their responses and that they have a superior ability to read the game.
The advantage of an expert eye was first demonstrated away from the sports pitch in intellectual games like chess. Research showed that grandmaster level players seem able to sum up a board at a glance. Given five seconds to look at a complex position, top players were more than 90 percent accurate in remembering the arrangement of the pieces, compared to good club players who could manage only 50 percent accuracy. It seems that grandmasters could "chunk" their perception of the board - breaking what they saw into a small number of meaningful units - so increasing the apparent bandwidth of their processing. Proof that it was the eye of experience that counted - rather than some generalised memory ability - lay in the fact that if the position of the chess pieces was random, not taken from a real game, the performance of both groups fell to the same level.
Over the past decade, sports psychologists have taken games such as hockey, basketball and soccer, testing players with slides of meaningful and random field positions, and found the same perceptual chunking process at work. It seems that while information may not enter the brain of top performers significantly faster, where the novice experiences only a blur of details, the expert sees a well-ordered set of possibilities. Such an ability to read a game allows the expert to anticipate and so paper over the split second gap that exists between reality and the brain's perceptual processes.
Queensland University's Abernethy says studies have shown that top performers are skilled at picking up early clues about what their opponents are about to do. For example, a group of novice and competitive badminton players were compared to see how quickly they could detect which way an opponent was about to flick a shuttle. While novices had to wait until they saw the racquet head start to move, the experts could guess much earlier from preliminary movements of the body and arm. "Experts do a good mechanical analysis of their opponent's playing action and can tell whether a shot is going cross- court or down the line. Sometimes the cue may be no more than movements in the large muscles of the chest," Abernethy says.
The same early response is true of tennis, where top players can tell from a server's action whether the ball will be land on their forehand or backhand, and of cricket, where a first class batsman will have decided whether to play off the back foot or front foot at least 100 milliseconds before a fast bowler has released the ball.
The interesting thing about such anticipation is that players are not conscious of the cues they are responding to. Abernethy says players go by a gut feeling - a sub-conscious recognition - and the only way to discover the cues they are actually using is to film the bowler's or server's action and then see what is happening in the frame where the expert's guess is made. "You can't teach people anticipation by saying look at point A or point B. It just has to come with practice and players may never really know what they are reacting to," says Abernethy.
Top athletes become so good at anticipation that their responses can seem almost instantaneous, as if no reaction gap existed. However, players can be cruelly exposed whenever a ball or opponent does something unexpected. Dr Peter McLeod of Oxford University carried out one of the best-known experiments to demonstrate the "incompressibility" of the blindspot in human reactions.
McLeod got three England batsmen, Allan Lamb, Wayne Larkins and Peter Willey, to face a bowling machine on a special matting pitch. Under the matting he placed a number of dowel rods to make the ball seam unpredictably. What McLeod found was that if the ball bounced sharply sideways closer than 200 milliseconds to the bat, then the batsmen would mis-play the ball every time. No correction was possible.
Anticipation studies would seem to suggest that the superior reactions of top performers are due largely to learning rather than any innate factor. But as Abernethy says, many people practice long and hard, yet few turn into a McEnroe or a Gascoigne. So it could be that the genetic component at play is a greater "trainability" of the nervous system. For example, some players might find it easier to develop anticipation skills because they have been born with better visuo-spatial and pattern recognition abilities. Certainly, one of the distinguishing features of both John McEnroe and Paul Gascoigne appears to be their imagination - their ability to visualise more possibilities in a given situation. However an alternative is that anticipation skills are, indeed, mostly learnt and that the genetic advantage lies at the output stage of stroke production.
Part of the impression that gifted athletes give of having infinite time comes from the silky smoothness of their shot execution. Again, some sports psychologists suspect that the genetic component of such motor skill may not lie in some pure measure of co-ordination but in the trainability of a person's nervous system. It has long been known from anecdotal evidence that in learning a skill, whether it is playing tennis, driving a car or learning to unscrew a bottle cap, there is a progression from crude conscious control of the action to smooth, automatic performance under the control of the cerebellum, the brain's specialised movement centre. But it is only recently, with the arrival of medical scanners able to track brain blood flows, that there has been convincing neurological evidence for such a "down-loading" of skills.
Dr John Stein, a physiologist at Oxford University, says in the early stages of learning a skill, the cortex and basal ganglia - roughly speaking, the higher conscious part of the brain - are most active. But as the skill is mastered, these areas drop out of the picture and control is taken over by the cerebellum. The cerebellum used to be thought of as just a memory store for motor routines - a blind, inanimate warehouse which produced stereotyped responses when triggered by a command from higher consciousness. However there is evidence to show that the cerebellum has considerable - if sub-conscious - intelligence. The cortex may set the global goals but the cerebellum can improvise to meet them.
Stein says support for this view comes from the discovery that there are two routes by which sensations reach the cerebellum. There is a cortical route where sensations are mapped first on the cortex (forming a conscious picture) and then passed down to the cerebellum. However there is also a direct route from the eyes to the cerebellum, by-passing the cortex. It is presumed this second route gives the quick delivery of information needed to control sub-conscious skills. The tempting conclusion is that gifted performers may simply be born with a "high-IQ" cerebellum. They may have a specialised motor genius that allows them to be more creative and agile in shot execution.
While it is too early to rule out such a "raw advantage" hypothesis, sports psychologist like Dr John Fazey of Bangor University believe the explanation could be more subtle. Fazey says it might simply be that some people are better at automating skills. Something in their make-up may allow them to down-load more of a complicated sporting action from clumsy conscious control to smooth sub-conscious performance.
Whatever produces a skilled cerebellum, the difference is easily noticed. Elite tennis and cricket players never seem to have to remind themselves to move their feet or turn their shoulders because these preparatory movements appear to be so fully under automatic cerebellar control. Their bodies snap into position of their own accord, leaving them poised to strike a clean shot. But weekend hackers find themselves forever wrestling with their own limbs, mechanically trying to get all the parts in the right place, then finding they are forced to make a cramped swipe because the ball is already upon them.
Somewhat unkindly, sports psychologists describe the hacker's plight as one of near skeletomuscular anarchy. Yet measurements of muscle and nerve activity show this to be an apt description. Where the nervous system of a skilled performer delivers small, accurate bursts of instructions to the limbs, producing a smooth response, that of the unskilled fires off blasts of often contradictory messages, creating a jerky, awkward movement as opposing muscles end up pushing and pulling at the same time.
Putting all this evidence together, sports science still cannot say precisely what makes a McEnroe or a Maradona, an Ali or an Agassi. It is obvious that years of dedicated training play a huge part. Also, differences in childhood stimulation may be important - Andre Agassi, for instance, was taught to bat a dangling balloon while still in his highchair. Such stories are typical of great athletes. Then there is the contribution of genes, although the likelihood is that the genetic component of exceptional skill has more to do with a capacity to benefit from training than with a set of raw ingredients like reaction speed.
However it seems that gifted performers are better at using anticipation to cover for a lagging brain. By reading their opponent's game, the skilled prime themselves to react to what they imagine will happen rather than waiting the 200 to 500 milliseconds it takes to actually become aware of what is happening. They create a virtual reality which allows them to act as if consciousness was indeed instantaneous. Then coupled to this perceptual priming is a smooth and intelligent execution of body movement. The gifted player's brain not only knows what it should do, it also has the automated skills to carry out the actions with a minimum of fuss and maximum of accuracy.
So the spectator in the stands is right after all.
The gifted are conjurors of time. They buy extra time with anticipation
and avoid losing time by automating their responses. The irony is that
if a McEnroe or a Gascoigne wants to appreciate their own skills then,
like any other spectator, they will have to wait the split second or so
it takes for their conscious awareness to catch up with the shots their
sub- conscious processes have just chosen to play. And any feeling they
might have had of being there at the time was just an illusion.
Libet's half-second delay
Experiments suggesting that conscious awareness lags behind reality by as much as half a second have been around for several decades now. But so difficult to stomach are the implications that many philosophers and psychologists still dismiss the results out of hand. In fact, the ability of tennis or cricket players to strike a ball within a tiny three to five millisecond time window is frequently cited as proof that consciousness must be the near instantaneous process that subjectively it appears to be.
Much of the controversial research has been carried out by University of California physiologist, Dr Benjamin Libet. What Libet has shown is that the nerve traffic generated by a sensory experience, such as an electrical pulse to the hand, takes just 20 milliseconds to reach the brain. But merely reaching the brain does not bring awareness. The activity has to persist for up to 500 milliseconds before a conscious experience is formed.
Libet uses several lines of evidence. In one experiment, Libet used an electrode to directly stimulate the touch centre of a subject's brain and found that the person did not register the pulse until after it had been on for half a second. In another, he found that if a pulse to the hand was followed up by a direct pulse to the brain 400 milliseconds later, the two merged to create a single enhanced pulse - as if the direct pulse could add its energy to the original still developing experience. Bizarrely, in both cases the subjects felt that the experience actually happened at the moment the pulses first arrived at the brain. Libet says it appears the brain can compensate for any processing lag by back-dating neural events and so creating a convincing illusion that we live in real time.
For safety reasons, most of Libet's work has been with weak electrical pulses at the limits of detection. But he says that while increasing the intensity of the stimulus may quicken the processing time - perhaps shortening it to 400 or perhaps even 300 milliseconds - this still leaves a large gap to be explained by anyone wanting to argue for near instantaneous consciousness.
The picture emerging from Libet's work and other related research is that sensations reach the brain within 20 milliseconds, but it takes at least 100 milliseconds for the brain to start to produce a reaction - and even this is of the well-rehearsed, sub-conscious variety where the brain has been primed as to the form of sensation to expect (such as a tennis serve heading towards the backhand) and so is able to react with the minimum of sensory processing. For novel or unexpected events, the brain has to spend up to 500 milliseconds before it produces the high-level settled picture that we call conscious experience.
Much of this half second may be devoted to the act of recognition - forging the link between sensation and stored memories that allows us to understand what is being seen against a backdrop of prior knowledge. It could be that it is only once the brain has clicked with an aha! of recognition that the sensation becomes manipulable by higher thought processes and so can enter the record of subjective experience.