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HOUR AFTER HOUR, day after day, the images flicker out. The programmes may change but the attention scarcely wavers. What is it about television that can mesmerise most of the Western world'? Why is the box addictive?
Australian researchers Fred and Merrelyn Emery claim to have hit upon the answer. Forget the programmes. they say. Whether it's the 'Ascent of Man' or a Bugs Bunny cartoon makes no difference at all. The important thing is the special kind of light that the TV emits. This is what stuns the brain cells and closes down the mind.
The glow from your TV screen, they say, is difficult for the human nervous system to cope with. This is firstly because it is 'radiant' rather than 'ambient' light and secondly because it is constantly switching on and off.
This is different from what we are used to. Human beings usually absorb information via 'ambient' light - light that has been reflected off objects. Light that started out from the sun or a light bulb is being reflected from the white spaces between the letters on this page and then travelling on into your eye.
But if you look now at the light source itself, you get radiant light at a much higher intensity. And this is something, say the Emerys, that the human brain cannot make much use of.
'The human perceptual system,' they say. 'evolved to deal with ambient light, not radiant light'. Nothing in evolution has prepared us for the luminous beams from the television set. Our ancestors' only similar experience might have been star-gazing or staring into the fire. And since we have no evolved system for extracting information from radiant light, 'We don't try to do it. We cut off'.
But TV light, they say, has a second important characteristic that sets it aside from other human experience. It is pulsating very rapidly and regularly - fifty or sixty times per second - (see box). This could produce 'habituation' - the brain gets used to the rhythm of the rapid changes and becomes so fixated by them that the picture itself fades into insignificance.
Television, they claim, can only be seen as a 'direct technological analogue of the hypnotist', with the brain effectively dominated by the signal. 'Provided the viewers continue to watch, they are unlikely to reflect on what they are viewing.'
The Emery's first put forward this startling hypnothesis on the physiological effect of TV back in 1975 while they were at the Australian National University of Canberra. Then in 1978 they appeared before a government committee enquiring into the effects of television on children and which recommended the 'priority be given to testing their theories'.
In fact relatively little was done; for all their efforts the Emerys found it almost impossible to get funds.
Most of their conclusions are based on experiments done by other people in related fields. These have usually involved assessing 'brain waves; - those electronic pulses which can be measured by tapping electrodes to the human scalp. The waves are of two main types. Alpha waves correspond to when the brain is relaxing and not processing information while the faster beta waves are produced when the brain is actively organising an analysing what it receives.
Dr Herbert E. Krugman of the US General Electric Company, for example, has compared the brain waves produces when reading magazines with those produced when watching television. Magazine reading produced largely beta waves while watching television for just 30 seconds produced a 'characteristic mode of response' with a predominance of the slower alpha waves - regardless of the programme.
Another experiment in the United States involved ten children watching their favourite TV programmes. It was thought likely that, since they were interested, their brains would go backward and forward between beta and alpha waves. But, as Dr Eric Peper of the San Francisco State University describes the results: 'They didn't do that, they just sat back. They stayed almost all the time in alpha. This means that while they are watching they were not reacting, not orienting, not focussing, just spaced out.'
That their most avid viewers are 'spaced out' a good deal of the time raises some awkward questions for the producers of television programmes. As Dr Krugman put it in a recent paper for the US Journal of Advertising Research:
'Students of media behaviour may yet confront the embarrassing fact that television audiences give close attention for long periods of time to stimulii that create no thought and very little recall'.
Like the Emery's, Dr Krugman is concerned to find out what the brain is doing all this time if it is not actively working. His approach is to look specifically at the distinction between left-brain and right-brain activity.
It is now accepted that the left side of the brain is used for organising and analysing information, whereas the right has much more general functions. Studies at the Department of Psychology at University College, Cardiff, in the United Kingdom have shown that left-brain attention, though much more accurate than that of the right-brain, tires quite quickly. The right-brain attention, however, shows almost no fatigue.
Krugman suggests that it is the right-brain that maintains the vigil over the tolerance of the TV screen and which only nudges the left-brain into alertness as needed. The tolerance of the right-brain for sustained attention is what accounts for childrens' ability to watch TV for hours on end. 'We should find nothing remarkable about this physiologically. 'he says. 'It is not more remarkable than the ability of a truck driver to drive his vehicle for many hours and to keep adequate watch on the road ahead.
'Of course both children and truck drivers may have to fight to stay awake because of the hypnotic monotony of the situation. This is not because their brain is working hard but because it is working very little.'
The remarkable aspect of the Emerys' proposition is that it provides a physiological reason - beyond that of boredom or fatigue —why the brain might be closing down. And, if it is the radiant, repetitive light signal that is doing the damage, there is not much that the makers of programmes or commercials can do about it.
Indeed the implications are so serious that you would have expected a whole flood of research programmes designed to test the proposition. In fact there has been almost nothing, The Emerys' themselves, who are now working at the University of Pennsylvania in the United States, have been trying for years to get the finances to back a major study.
'We have had neurophysiologists standing by and research proposals in for as little as $11,000,' says Merrelyn Emery, 'but no one wants to fund them. My suspicion is that there are a lot of people terrified that we may well be right.'
The implications for the makers of educational programmes on television would be radical. Fred Emery is particularly forthright. Giving evidence before the Australian government commission, he said: 'If we are going to show TV in school hours then we have to be very clear about what we are doing: we are wasting our time.'
And if it is the fluctuating light that is closing down the brain then there are implications possibly even more serious. The Emerys suggest that those parts of the brain that are being closed down are the ones that normally exert control over more basic instincts. Without such control the old or primitive brain, which we share with lower order species, has much more of a free rein and long-term viewing could produce anything from irritability to aggression. Violent behaviour that results from watching television may thus come not from the programmes but from the medium itself.
It is clear however that the 'habituation' effect that the TV screen has cannot be totally effective. People who are viewing screens in an active way such as those reading visual display units on computers are obviously managing to overcome to a great extent whatever effect there is. In the first place they are moving their eyes to read, whereas the TV viewer tends to sit far enough back so that almost no eye movement is needed to take in the screen. Then again, as with reading a magazine or a book, the brain is constantly refreshed and rested by looking away or choosing another piece of information to be studied.
Herbert Krugman' s conclusion from the evidence that has been gathered is that educational TV will have to work much harder to imitate the action of reading or of being in the presence of a good teacher. To actually get people to think while they are watching, he says, the producers should be much more tolerant of pauses - rest stops for the tired brain. Timing is everything,
That people are not actively thinking as they are viewing does not, however, mean that the images are not going into - and being retained by - the brain. It is generally accepted that politics, for example, has become much more a matter of TV image than argument. That the electorate in the United States is so tolerant of President Reagan, for example, would make more sense if watching his press conferences were considered as a right-brain rather than a left-brain activity. It is how he appears as an actor that makes the impact.
The same would be true for advertising. As Fred Emery puts it: 'Television is very good at familiarising people with something. Hence its great value in advertising - especially for launching new products. It gets over the strangeness straightaway'. Again in news or current affairs broadcasts the likelihood is that people have become more familiar with the sights of Beirut or El Salvador.
But when it comes to the mechanism of learning from the television screen, we still seem, after all these years, to be in fairly unknown territory.
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