TEST pilots at NASA push human performance to its limits. They must climb
into untried, high-performance aircraft and fly them at high speed while taking
them through complex test procedures. To stay alive they need the ultimate
mental edge. And to help gain that edge, NASA pilots have a trade secret.
Before taking a new plane for that first flight, NASA pilots jack up the
speed of their simulators until they run faster than 鈥渞eal-time鈥�. Being trained
to cope even when events happen twice as fast as in reality, makes the pilots
feel they can think faster and stay calmer once they are airborne and their
lives are on the line.
Is such training just a curiosity for people who live on the edge? Simulator
enthusiasts claim that it may have a much wider impact. What works for the
military could provide a tonic for all hard working minds. A pep-up computer
game鈥攐r better still, a thorough perceptual work-out in virtual
reality鈥攃ould boost the speed at which ordinary people think, they
say.
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Dutch Guckenberger, a research fellow at the simulator manufacturer, ECC
International in Orlando, Florida, believes that humans are surprisingly plastic
in their speed of thought. He says that most of us dawdle along at a lazy 10 or
20 鈥渄ecision cycles鈥� a second. But if retuned by the demands of an artificial
reality, this could be boosted to 30 or even 40 cycles a second. 鈥淵ou could take
a slow man and turn him into a fast man,鈥� says Guckenberger. 鈥淔rom our work with
above real-time training, the evidence is that a 30 per cent performance
increase could be a normal gain.鈥�
On the strength of these claims the US military funded new studies with F-16
fighter pilots learning emergency drills and tank gunners practising shooting
down enemy helicopters. Guckenberger says training at an accelerated rate in a
simulator left personnel with more time to carry out complex tasks in real-life
situations, giving green recruits the battle-hardened reflexes of veterans.
But computer games to boost your IQ? Is it possible that training the brain
to work faster could also make you smarter? First it was subliminal learning
tapes and biofeedback machines: then smart drugs were touted as the short-cut to
a sharper mind. How long before CD-ROM hypertime game trainers are the latest
fad in the consciousness-expanding industry? The dream of instant
braininess鈥攜ours for just 拢99.99 plus postage鈥攎eans that there
will always be a market for such products. But does science give us reason to
believe that we could ever benefit from a quick fix solution? Is IQ based on
some simple brain property鈥攕uch as the level of a vital neurotransmitter,
a few key genes, or the tuning of an inner perceptual clock鈥攖hat would
make it susceptible to some gross form of manipulation like gene therapy or
virtual reality training?
Opinion on this is divided. Many psychologists are convinced that IQ is a
matter of high-level skills such as logic and abstract thinking. They see the
brain as such a complex system that any variation in its performance must be due
to some incredibly subtle details of its design, and so there can be no simple
way of making it run better, or boosting intelligence. But another group of
psychologists takes the opposite view. They reason that the brain grows from a
relatively limited number of genes, so some very simple factors will have to
dictate its level of performance. Something about the basic speed or efficiency
of a person鈥檚 neurons will have to account for much of the observed variation in
intelligence.
Chris Brand, a psychologist at the University of Edinburgh, argues in his new
book, The g Factor, that serious scientists can no longer deny that
intelligence has a biological component. He says that underlying most cognitive
activities is a single mental power called general intelligence or g.
Brand says that comparisons of twins reared apart and other such studies now
strongly suggest that about 45 per cent of the variance found in IQ (or, at
least, whatever it is that IQ tests measure) is the result of inherited factors.
Differences in the home environment, says Brand, account for just 10 per cent of
the variance in IQ scores, with just 5 per cent down to other environmental
influences such as schooling. If this view is correct then much of IQ has its
roots in basic biological factors which may be open to manipulation. But what is
it about the working of brains that might account for differences in IQ?
The idea that intelligence might be linked to nerve conduction speed or
perceptual efficiency dates back to the work of Francis Galton, the Victorian
gentleman-scientist. At his London testing centre, Galton compared the reaction
times and sensory acuity of labourers and middle-class subjects. When he failed
to find any correlations, psychologists moved on to develop the pencil and paper
reasoning tests that are familiar as IQ tests today. Only a few isolated
figures, such as Arthur Jensen from the University of California, Berkeley, kept
looking for evidence that sheer neural speed might play a role in
intelligence.
Trunk cabling
Neuroscience certainly gives reason to doubt that raw conduction speeds would
count. After all, the brain does not use just one kind of nerve. The conduction
speed of a nerve fibre depends on its size and the thickness of its fatty
insulation. On the kind of trunk cabling used to connect the eye to the brain or
send a muscle command down to the hand, impulses zip along at just under 90
metres per second. But inside the brain, the wiring is generally slower and more
varied. Impulses tend to crawl along at between 1 and 9 metres per second.
That the brain uses such a mix of nerves would seem to kill off any simple
theory of conduction speed. Yet in recent years, a number of researchers have
claimed to have found positive correlations between IQ scores and neural speed.
Perhaps the most radical are studies by Philip Vernon at the University of
Western Ontario in Canada who has matched IQ to the speed of impulses in the
median nerve of the arm. Using electrodes at the elbow and armpit to time the
reaction to a small electric shock at the wrist, Vernon claims that variations
in conduction velocity show a modest, yet significant, correlation.
Unfortunately, even those sympathetic to conduction-time theories of IQ, such as
Jensen and Hans Eysenck at the Institute of Psychiatry in London, have been
unable to replicate these findings.
Another approach has been to measure mental processing speeds using evoked
response potential techniques. An ERP is a scalp electrode recording of the snap
of electrical activity produced in the brain by a simple stimulus, such as a
flash of light or the reversal of a chequerboard pattern. Nothing can be seen in
a single trial because the brain produces too much background noise. But by
putting someone through hundreds of trials and averaging the results, the
background activity cancels itself out, leaving just the rises and falls in
neural activity associated with processing the stimulus.
With a stimulus such as a reversing chequerboard, the first big ERP peak
comes after about a tenth of a second. This rise in polarity is taken to be the
building of a primary sensory map in the visual cortex. Other peaks follow in
different parts of the brain and these are believed to be related to thoughts
about the meaning or significance of the sensory information.
The conventional wisdom is that ERP timings vary little from person to
person. Take a common measure, such as the P100 spike, which occurs 100
milliseconds after the sharp visual jolt of a chequerboard reversal. Mike Rugg
from the University of St Andrews says that the variation in P100 times is so
small that doctors use it as a benchmark for diagnosing conditions that damage
nerves, such as multiple sclerosis. What鈥檚 more, only a few milliseconds are
actually taken up by the transmission of impulses down the optic nerve from eye
to brain. The rest of the 100 milliseconds is used up in transduction of light
by pigments in the retina and by the visual cortex as it organises its
reaction.
However, even though variation in P100 is low, there will still be a small
percentage of people with ERPs beyond 110 milliseconds, or below 90
milliseconds. Jensen and Ed Reed at the University of Toronto, believe that this
leaves plenty of room for speed differences to count: the two have reported a
small, but constant, correlation between P100 times and IQ scores. Jensen uses
this to argue that if ERP differences over the first leg of the sensory
processing journey reflect a general efficiency of wiring in the brain, then raw
conduction advantages could account for as much as 25 per cent of the variance
in IQ scores.
The ERP approach to measuring brain speed has been replicated by a number of
laboratories over recent years. However many feel that neural speed alone is
probably, after all, a little too simple to explain advantages in intelligence.
The belief that the quick movement of nerve traffic must be good is based on a
rather old-fashioned, computational view of the brain. In the classic serial
processing computer, information is chopped up and passed through a sequence of
calculating steps. The faster each step is completed, the sooner a computer
completes its program.
But modern neuroscience sees the brain as a dynamic neural network. A 鈥渟tate
of information鈥� has to grow organically, evolving under the pressures of
positive and negative feedback until it reaches a state of balanced tension. In
such a network, it is not the speed of traffic along individual wires that
counts but the performance of the entire network as it settles into a 鈥渟olution
state鈥�. So ERP studies might really be measuring reliability rather than
speed.
Less speed, more synchrony
Pat Rabbitt at the University of Manchester used to be sceptical about simple
biological explanations of IQ but has been persuaded by his own work on
perception timing tasks. He points out that a person鈥檚 ERP score is the average
of hundreds of trials. Analysis of these averages suggests that high IQ scorers
are not markedly quicker, but exhibit less overall variation. Their averages are
lower because fewer trials are skewed by the occasional lagging response.
鈥淲hen you look at the development of reaction times in kids, what you get is
fewer slow responses occurring as they get older, rather than more fast ones,鈥�
says Rabbitt. The same phenomenon shows up in other mental tasks such as judging
short spans of time. 鈥淚f we ask people to estimate time periods of under a
second, clever and less clever subjects have similar averages, but the variance
of one is smaller than the other,鈥� he says.
This picture fits with recent findings by Peter Caryl, Brand鈥檚 colleague at
the University of Edinburgh. Caryl says he looked at the ERPs of people who had
to judge which of two lines was longest when the pair was flashed up on a
screen. The ERPs of high IQ scorers tended to show a steeper, more pronounced
rise, as if their brains were responding with sharper synchrony. The bunching of
ERP times would fit the idea that some brains form mental representations that
are more precise.
Yet both Caryl and Rabbitt warn against overinterpreting these findings. As
Rabbitt points out, if it turns out to be network performance rather than plain
neural conduction speed which is basic to the biology of intelligence, then that
is really quite a complex 鈥渟imple factor鈥�. At the moment, researchers can only
guess what it might take to tune a brain network to optimum pitch. All sorts of
variables, from the number of branches on neurons to the replenishment rates of
neurotransmitters, could play a part in producing a crisp response.
Caryl adds that as soon as you take a dynamic network view of the brain, it
also becomes difficult to separate 鈥渦pstream鈥� from 鈥渄ownstream鈥� processes. The
old cognitive science model saw sensory information being mapped in the visual
cortex then being analysed for meaning and content by a succession of filters.
But in a neural network, feedback from high-level brain areas will flood down to
affect the primary visual map even as it forms.
Indeed, there is now plenty of evidence that the brain runs ahead of itself,
anticipating what will happen in the next few moments so as to guide its sensory
processing. When we reach for a door handle, our brains will already have
anticipated how it should feel. We only notice this ever-present habit of
anticipation when something goes wrong鈥攚hen someone pulls the door open
from the other side just as you are about to grab the handle. The unexpected
causes sensory confusion and we find ourselves briefly flummoxed.
Boost to the system
If feedback intimately connects high-level processes to basic sensory
processes, then people with high IQ might have their advantages elsewhere, says
Caryl. The crispness of an ERP might reflect the efficiency of priming and
attention-directing processes further up the brain. In that case, even a strong
correlation between some apparently basic neural property and IQ would not mean
that one was causing the other. A fast brain could be just one that anticipates
better.
So intelligence researchers have no answers: just some firmer correlations
and a few ideas about possible neural network properties. As a result, most are
reluctant to speculate about whether intelligence could be boosted by some mind
drug or perceptual training technique. Nevertheless, the main argument against
these and other physical interventions is that if peak mental performance
depends on delicately tuned neural networks, then these methods would be like
jamming a screwdriver into the front of your hi-fi.
The accepted view on mental training has been that any benefit is normally
limited to the skill being practised. According to Rabbitt, playing a lot of
chess, doing crosswords鈥攐r even filling in IQ questionnaires鈥攎akes
you better at those activities, but will not give you a general boost to the
system.
So where does this leave Guckenberger and his dreams of using 鈥渉ypertime鈥�
training to quicken a person鈥檚 thinking? Firstly, his attempts to explain a
training effect in terms of an increase in decision cycles owes too much to the
outdated, serial computer model of the way the brain works. Perhaps rather than
fast and slow man, Guckenberger should be talking about the difference between
precise and blurred man. But more importantly, a consultant who looked into
accelerated simulator training for NASA back in the 1970s came up with a
relatively straightforward explanation for the effect.
Staff at NASA鈥檚 Dryden testing ground in Edwards, California, first stumbled
upon above real-time training in the early 1970s while working on the F-15 jet
fighter project. The prototype of the F-15 was actually a remotely piloted model
glider designed to test the controls and flight surfaces. The pilot sat in a
mock cockpit on the ground and flew the model via a radio link. After preparing
for hours in a conventional flight simulator鈥攆lying a
computer鈥攑ilots still complained of feeling rushed when they began flying
the model, so NASA engineers tinkered with the simulator to let pilots adjust
its speed to what seemed a psychologically realistic level. This turned out to
be about 1.4 times as fast as real-time. Ever since, NASA Dryden has routinely
used speeded up simulators for the final stages of flight training.
Simulator consultant Robert Hoey investigated the basis of the effect.
Hooking up pilots to a heart monitor, Hoey found that they were much more
relaxed in a simulator than when flying a plane. Even just knowing that they
were flying a radio-controlled glider was enough to produce an extra rush of
adrenaline.
Such physical arousal is a normal response that prepares a person to take
violent action in potentially dangerous situations. Arousal also has a
psychological effect, altering the balance of certain neurotransmitters and
lowering sensory thresholds, so making us feel more 鈥渏umpy鈥�. In neural network
terms, the weights of connections are adjusted so the network is more likely to
respond to partial information, allowing the brain to trade off urgency against
a greater probability of errors.
Hoey argued that under these conditions, the brains of test pilots would have
more trouble dealing with the kind of detached, intellectual skills needed to
check out a new plane. Test pilots, unlike normal pilots, have to follow a
strict plan of manoeuvres while watching for problems. Training under
accelerated conditions in a simulator appeared to be a good way of mimicking the
effects of added psychological stress, so that during the eventual flight the
pilots felt less rushed and better able to cope.
Guckenberger鈥檚 own more recent studies support this explanation. In his work,
F-16 pilots reaped the most benefit during enemy avoidance drills which involved
a complicated sequence of manoeuvres. The pilots had to deal with a lengthy
checklist while under severe stress. Guckenberger found much less evidence that
above real-time training gave an advantage when learning ordinary flight skills.
Likewise, the tank gunnery exercise was peculiarly dependent on making complex
calculations under pressure.
This suggests that time-pressured training may only help in situations that
mix high arousal with a need to preserve a measure of analytical detachment. A
speeded-up virtual reality environment might well prove valuable for training
traders in the City, where millions ride on split-second decisions; surgeons,
whose actions can mean life or death; and even people who suffer exam nerves. In
fact, it could be useful for anyone who has to use skills in stressful
conditions. But it is unlikely to deliver the general IQ boost talked about by
Guckenberger.
Still, Guckenberger is not downhearted. He admits that he has no hard
evidence that above real-time training could be harnessed as other than a way of
simulating the effects of psychological stress. But he can still dream. At the
moment he is toying with a computer display that takes you down a road of
columns, with the columns zipping by faster and faster. 鈥淪taring at the screen
might pick up the brain rate,鈥� says Guckenberger. 鈥淚t鈥檚 worth a try.鈥�