by John Coates
Or consider one of the most dangerous positions in the sporting world, the short distance infielder in cricket. On a cricket field, one brave soul plants himself, crouched at the ready, a mere 14 to 17 feet from the batsman, with some coming in even closer than that. Here, without the benefit of gloves, he attempts either to catch the ball as it explodes off the bat, or clear out of the way. A cricket ball, slightly larger than a baseball and much harder, rebounds off a swinging bat at speeds of up to 100 miles an hour. The fielder facing this ball must first take care not to be hit by the bat itself, and then has as little as 90 milliseconds, less than a tenth of a second, to react to the incoming projectile. One of the closest of these positions is appropriately called the silly point, and in here, this close to the batsman, death can occur. One Indian player, Raman Lamba, was killed by a ball to the temple while he was fielding at another position frighteningly close to the batsman.
Equally deadly projectiles, ones responsible for far more injuries, can be found in contact sports like karate and boxing, where punches have been clocked at terrifying speeds. Norman Mailer, reporting on the Rumble in the Jungle, when Muhammad Ali fought George Foreman in the Zairean capital Kinshasa in 1974, describes Ali warming up in the ring, ‘whirling away once in a while to throw a kaleidoscope-dozen of punches at the air in two seconds, no more – one-Mississippi, two-Mississippi – twelve punches had gone by. Screams from the crowd at the blur of the gloves.’ If Mailer’s numbers are right, one of Ali’s punches would run its course from beginning to end in about 166 milliseconds, although Foreman would only have had half that time to avoid it. In fact, later, more scientific measurement timed Ali’s left jab at little more than 40 milliseconds.
Fig. 4. Speed of reactions. Jo-Wilfried Tsonga reaching for a volley at Wimbledon, 2011. If we assume his opponent, Novak Djokovic, hit a backhand from the baseline at about 90 mph, then Tsonga had a little over 300 milliseconds to respond.
It should come as no surprise that athletes facing fast-moving objects like cricket balls or ice hockey pucks frequently fail to intercept them (or in boxing to avoid them). But if an athlete succeeds, say, one time out of three, as a good baseball player does when at bat, his success rate approaches that of many predators in the wild. A lion, for example, closing in on an antelope, or a wolf on a deer, catches its prey on average one time out of three. In sport, as in nature, competition has pushed reaction times right to the frontier of the biologically possible.
Unfortunately, those of us not gifted with the reaction times of an Olympic athlete are nonetheless often called upon to respond with something like their speed, especially while on the road. A driver speeding at 70 miles an hour has as little as 370 milliseconds to avoid a car 75 feet in front that has mistakenly swerved into the oncoming lane. Here a success rate of one out of three still leaves a lot of car crashes.
The speed demanded of our physical reactions, in the wild, in sports, on the road, even in the financial markets, raises troubling questions when lined up against certain findings in neuroscience. Take this curious fact, for instance: once an image hits the retina, it takes approximately 100 milliseconds – that is a full tenth of a second – before it consciously registers in the brain. Pause for a moment and contemplate that fact. You will soon find it profoundly disturbing. We tend to think, as we survey the world around us or sit in the stands of a sporting match, that we are watching a live event. But it turns out that we are not – we are watching news footage. By the time we see something, the world has already moved on.
The trouble stems from the fact that our visual system is surprisingly slow. When light hits our retina, the photons must be translated into a chemical signal, and then into an electrical signal that can be carried along nerve fibres. The electrical signal must then travel to the very back of the brain, to an area called the visual cortex, and then project forward again, along two separate pathways, one processing the identity of the objects we see, the ‘what’ stream, as some researchers call it, and the other processing the location and motion of the objects, the ‘where’ stream. These streams must then combine to form a unified image, and only then does this image emerge into conscious awareness. The whole process is a surprisingly slow one, taking, as mentioned, up to one tenth of a second. Such a delay, though brief, leaves us constantly one step behind events.
Neuroscientists have discovered another problem with the idea that we are watching the world live. An important part of this idea is the notion that our eyes objectively and continuously record the scene before us, much like a movie camera. But eyes do not operate like this. If we continuously recorded the visual information presented to us, we would waste a great deal of time (and probably suffer constant headaches) looking at blurred images as our eyes pan from one scene to another. More importantly, we would be swamped by the sheer amount of data, most of which is irrelevant to our needs. Live streaming takes up an enormous amount of bandwidth on the internet, and it does so as well in our brains. To avoid a needless drain on our attentional resources, our brain has hit upon the tactic of sampling from a visual scene, rather than filming it. Our eyes fix on a small section of our visual field, take a snapshot, then jump to another spot, take a snapshot, and quickly jump again, much like a hummingbird nervously flitting from flower to flower. We are largely unaware of this process, and do not see a blur when our eyes shift location because, remarkably, the visual system stops sending images up to consciousness while it jumps from scene to scene. Furthermore, we are unaware of these jumps and intervening blackouts because our brain weaves these images seamlessly into something that does appear much like a movie. We can perform up to five of these visual jumps per second, the minimum amount of time required for a shift in view being therefore one fifth of a second.
If we return to sports, we can see that some numbers do not add up. How can a cricketer at the silly point catch (or duck) a ball in under a tenth of a second if he is not even aware of it yet? How can he direct his attention to the ball if it takes him twice as long just to move his eyes? And when dealing with these numbers we have not even begun to consider the additional 300–400 milliseconds required for an elementary cognitive decision or inference, and the 50 milliseconds or so it takes for a motor command to be communicated by nerves to our muscles. The picture conjured by these numbers is one of an infielder frozen in the readiness stance, eyes fixed like a waxwork statue, while a projectile shudders past his immobile and fragile head.
The same questions we ask about athletes can be asked, and with more urgency, beyond the sport field. How can we humans survive in a brutal and fast-moving world if our consciousness arrives on the scene just after an event is over? This is a baffling question. But asking it allows us to see what is wrong with the notion of the brain as a central processor, taking in objective information from the senses in the manner of a camera, processing this information rationally, consciously and discursively, deciding on the appropriate and desired action, and then issuing motor commands to our muscles, be they larynx or quadriceps. Each of these steps takes time, and if we were indeed programmed to behave this way, then life as we know it would be very different. If we had to think consciously about every action we took, sporting events would become odd, slow-motion spectacles that few people would have the patience to watch. Worse, in nature and in war we would have long ago fallen prey to some quicker beast.
I, CAMERA?
It turns out that there is something wrong with each step in this supposed chain of mental events. The eye takes snapshots rather than movies; but even these snapshots are not a photographic and objective record of the outside world. All sensory information comes to us tampered with. Like the news on TV, it is filtered, warped and pre-interpreted in a way designed to catch our attention, ease comprehension and speed our reactions.
Take for instance the ways in which the brain deals with the problem of the one-tenth-of-a-second delay between viewing a moving object and becoming consciously aware of it. Such a delay puts us in const
ant danger, so the brain’s visual circuits have devised an ingenious way of helping us. The brain anticipates the actual location of the object, and moves the visual image we end up seeing to this hypothetical new location. In other words, your visual system fast-forwards what you see.
An extraordinary idea, but how on earth could we ever prove it to be true? Neuroscientists are devilishly clever at tricking the brain into revealing its secrets, and in this case they have recorded the visual fast-forwarding by means of an experiment investigating what is called the ‘flash-lag effect’. In this experiment a person is shown an object, say a blue circle, with another circle inside it, a yellow one. The small yellow circle flashes on and off, so what you see is a blue circle with a yellow circle blinking inside it. Then the blue circle with the yellow one inside starts moving around your computer screen. What you should see is a moving blue circle with a blinking yellow one inside it. But you do not. Instead you see a blue circle moving around the screen with a blinking yellow circle trailing about a quarter of an inch behind it. What is going on is this: while the blue circle is moving, your brain advances the image to its anticipated actual location, given the one-tenth-of-a-second time lag between viewing it and being aware of it. But the yellow circle, blinking on and off, cannot be anticipated, so it is not advanced. It thus appears to be left behind by the fast-forwarded blue circle.
The eye and brain perform countless other such tricks in order to speed up our understanding of the world. Our retina tends to focus on the front edge of a moving object, to help us track it. We process more information in the lower half of our visual field, because there is normally more to see on the ground than in the sky. We group objects into units of three or four in order to perceive numbers rather than count them, a process, known as subitising, that comes in handy when assessing the number of opponents in battle. We rapidly and unconsciously assume an object is alive if it moves in certain ways, regularly changing direction say, or avoiding other objects, and then pay it closer attention than we would if it was inanimate.
Our reaction times can also be speeded up by relying more on hearing than vision. That may seem counter-intuitive. Light travels faster than sound, much faster, so visual images reach our senses before sounds. However, once the sensations reach our eyes and ears, the relative speeds of the processing circuits reverse. Hearing is faster and more acute than seeing, about 25 per cent so, and responding to an auditory cue rather than a visual one can save us up to 50 milliseconds. The reason is that sound receptors in the ear are much faster and more sensitive than anything in the eye. Many athletes, such as tennis and table-tennis players, rely on the sound a ball makes on a racket or bat as much as on the sight of its trajectory. A ball hit for speed broadcasts a different sound from one sliced or spun, and this information can save a player the precious few milliseconds that separate winners from losers.
If we now add up all the time delays between an event occurring in the outside world and our perceiving it, we discover the following lovely fact. For events occurring at a distance, we see them first and hear them with a delay, as we do, for example, when seeing lightning and hearing the thunder afterwards. But for events taking place close to us, we hear them, because of our rapid auditory system and relatively slow visual one, slightly in advance of seeing them. There is, though, a point at which sights and sounds are perceived as occurring simultaneously, and that point is located about ten to fifteen metres from us, a point known as the ‘horizon of simultaneity’.
Could our more rapid hearing provide traders with an edge over competitors? Right now, all price feeds onto a trading floor are visual images on a computer screen. But the technology does exist for supplying audio price feeds. These have already been supplied to blind people, and apparently they sound much like an audiocassette on fast forward. Such a feed could give traders a 40-millisecond edge. That is not much time. But who knows, it could prove decisive when hitting a bid or lifting an offer during a fast market.
Bringing a trader’s hearing into play may have a further advantage. Research in experimental psychology has found that perceptual acuity and general levels of attention increase as more senses are involved. In other words, vision becomes more acute when coupled with hearing, and both become more acute when coupled with touch. The explanation ventured for these findings is that information arriving from two or more senses instead of just one increases the probability that it is reporting a real event, so our brain takes it more seriously. Many older trading floors may have inadvertently capitalised on this phenomenon, because they came equipped with an intercom to the futures exchanges, with an announcer reporting bond futures prices: ‘One, two … one, two … three, four … fours gone, fives lifted, size coming in at six …’ and so on. With the advent of computerised pricing services, many companies felt this voice feed was antiquated and discontinued the service. Yet by bringing in a second sense it may have been an effective way of sharpening attention and reactions among the traders.
KNOWING BEFORE KNOWING
All these ad hoc adjustments to the information being transmitted to your conscious brain keep you from falling hopelessly behind the world. But the brain has an even more effective way of saving you from your fatally slow consciousness. When fast reactions are demanded it cuts out consciousness altogether and relies instead on reflexes, automatic behaviour and what is called ‘pre-attentive processing’. Pre-attentive processing is a type of perception, decision-making and movement initiation that occurs without any consultation with your conscious brain, and before it is even aware of what is going on.
This processing, and its importance to survival, has nowhere been better described than in the extraordinary book All Quiet on the Western Front, written by Erich Maria Remarque, a soldier who served in the trenches during the First World War. Remarque explains that to survive on the front soldiers had to learn very quickly to pick out from the general din the ‘malicious, hardly audible buzz’ of the small shells called daisy cutters, for these were the ones that killed infantry. Experienced soldiers could do this, and developed reactions that kept them alive even amid an artillery bombardment: ‘At the sound of the first droning of the shells,’ Remarque tells us, ‘we rush back, in one part of our being, a thousand years. By the animal instinct that is awakened in us we are led and protected. It is not conscious; it is far quicker, much more sure, less fallible, than consciousness. One cannot explain it. A man is walking along without thought or heed; – suddenly he throws himself down on the ground and a storm of fragments flies harmlessly over him; – yet he cannot remember either to have heard the shell coming or to have thought of flinging himself down. But had he not abandoned himself to the impulse he would now be a heap of mangled flesh. It is this other, this second sight in us, that has thrown us to the ground and saved us, without our knowing how.’
Neuroscientists have long known that most of what goes on in the brain is pre-conscious. Compelling evidence of this fact can be found in the work of scientists who have calculated the bandwidth of human consciousness. Researchers at the University of Pennsylvania, for example, have found that the human retina transmits to the brain approximately 10 million bits of information per second, roughly the capacity of an ethernet connection; and Manfred Zimmermann, a German physiologist, has calculated that our other senses record an additional one million bits of information per second. That gives our senses a total bandwidth of 11 million bits per second. Yet of this massive flow of information no more than about 40 bits per second actually reaches consciousness. We are, in other words, conscious of only a trivial slice of all the information coming into the brain for processing.
A fascinating example of this pre-conscious processing can be found in a phenomenon known as blindsight. It became a topic first of curiosity and then of medical concern during the First World War, when medics noticed that certain soldiers who had been blinded by a bullet or shell wound to the visual cortex (but whose eyes remained intact) were nonetheless ducking their heads w
hen an object, such as a ball, was tossed over their heads. How could these blind soldiers ‘see’? They were seeing, it was later discovered, with a more primitive part of the brain. When light enters your eye its signal follows the pathways, described above, back to your visual cortex, a relatively new part of the brain. However, part of the signal also passes down through an area called the superior colliculus, which lies underneath the cortex, in the midbrain (fig. 5). The superior colliculus is an ancient nucleus (collection of cells) that was formerly used for tracking objects, like insects or fast-moving prey, so that our reptilian ancestors could, say, zap it with their tongues. Now largely layered over by evolutionarily more advanced systems, it nonetheless still works. It is not sophisticated: it cannot distinguish colour, discern shape or recognise objects, the world appearing to the superior colliculus much like an image seen through frosted glass. But it does track motion, capture attention and orient the head towards a moving object. And it is fast. Fast enough, according to some scientists, to account for a batter or infielder’s rapid tracking of a moving ball. Lastly, blindsight operates without us ever being aware of it.
Fig. 5. The visual system. Visual images travel by electrical impulses projected from the retina to the visual cortex at the back of the brain. They are then sent forward along the ‘what’ stream, which identifies the object, and the ‘where’ stream, which identifies its location and movement. An older, faster route for visual signals travels down to the superior colliculus where fast-moving objects can be tracked.