While controversy continues to surround the way the content screen media affects our thoughts and behaviour, a growing body of empirical evidence is indicating that watching television causes physiological changes, which are really not for the better. Most of these effects occur irrespective of the type of programme that people watch – whether it is violence or teletubbies (fun, games, etc). It is the medium, not the message.
Watching television is now the industrialized world’s main pastime, taking up more of our time than any other single activity except work and sleep.
However, biological sciences are fast becoming the new arena for examining the effects of society’s favourite pastime. And in industrialized societies, the findings are set to recast the role of the television screen as the greatest unacknowledged public health issue of our time.
Attention and Cognition
The general guidelines recommend that children under the age of two should not watch TV or any form of screen entertainment at all because television “can negatively affect early brain development” and that children of all ages should not have a television in their bedroom.
Early exposure to television during critical periods of synaptic development would be associated with subsequent attention problems.
Little thought has gone in to the potentially crucial role that early childhood experiences may have on the development of attentional problems.
Children who watch television at ages one and three had a significantly increased risk of developing such attentional problems by the time they were seven.For every hour of television a child watched per day, there was a significant increase in attentional problems. New brain-imaging studies have found that different parts of the brain deal with different types of attention and so there can be types of attentional damage.
Television elicits our instinctive sensitivity to movement and sudden changes in vision or sound.
The orienting response to television is apparent almost from birth: infants, when lying on their backs on the floor, will crane their necks around 180 degrees to watch. Twenty years ago, studies began to look at whether the medium of television alone – the stylistic techniques of cuts, edits, zooms, criticism, sudden noises, not the content of the programme – activates this orienting response. This was done by considering how electroencephalogram (EEG) responses were affected.
It is known that these stylistic techniques can indeed trigger involuntary physiological responses of detecting and attending to movement – dynamic stimuli – something television has in abundance. These techniques also cause us to continue to pay attention to the screen.
Most of our stares at a television screen are highly prone to termination, lasting less than three seconds. But as we continue to stare, it becomes progressively less fragile, gaining a powerful attentional inertia after about 15 seconds. By increasing the rate of edits – camera changes in the same visual scene – one can increase the subject’s physiological excitement along with attention to the screen.
Others have compared the attentional demands of children’s programmes made in the public and private sectors, that is, commercial television. Children’s television programmes increasingly demand constant attentional shifts by their viewers but do not require them to pay prolonged attentional shifts to given events.
Researchers are now asking if it is possible that television’s conditioning of short attentional span may be related to some school children’s attentional deficits in later classroom settings and whether the recent increase of attention deficit disorders in children of school going age might be a natural reaction to our modern, fast culture – an attention deficit culture.
Compared to the pace with which the real life unfolds and is experienced by young children, television portrays life with the fast-forward button fully pressed. Rapidly changing images, scenery and events and high-fidelity sounds are highly stimulating and extremely interesting. Television is the flavour enhancer of the audiovisual world, providing unnatural levels of sensory stimulation.
The actual currency used to pay off and corrupt the reward system may come in the form of the neurotransmitter, dopamine. The release of dopamine in the brain is associated with reward. In particular, dopamine is seen as rewarding us for paying attention, especially to things that are novel and stimulating. This under-functioning of dopamine may fail to reward the brain’s attention systems, so they do not function effectively.
Interestingly, adults with attention deficit disorder, who are given dopamine-boosting methylphenidate (Ritalin) before doing a maths test, find it easier to concentrate. This is partly because the task seems more interesting. More research is needed into the extent to which this reward system involving dopamine (and other neurotransmitters) is set in childhood by exposure to electronic media such as television.
Early exposure to television is now found in another childhood condition. The very latest research on communication disorders suggests that early childhood television viewing may be an important trigger for autism (communication disorders), the incidence of which appears to be increasing.
Research into Alzheimer’s disease are concluding that each additional daily hour is associated as a risk factor. This, in turn, leads to cognitive impairment in all measures, including attention, memory and psycho-motor speed. For example, a study looking at differences in cerebral blood flow between children playing computer games and children doing very simple repetitive arithmetic adding single digit numbers found that computer games only stimulated activity in those parts of the brain associated with vision and movement as compared to arithmetic-stimulated brain activity, adding single-digit, numbers-activated areas throughout the left and right frontal lobes.
Television viewing among children under three years of age is found to have a negative effect on mathematical ability, reading recognition and comprehension in later childhood.Along with television viewing displacing educational and play activities, it is suspected that this harm may be due to the visual and auditory output from the television actually affecting the child’s rapidly developing brain.
A 25-year study, tracking children from birth has recently concluded that television viewing in childhood and adolescence is associated with poor educational achievement by 30 years of age. Early exposure to television may have long-lasting adverse consequences for educational achievement and later, the socio-economic status and well-being.
An increasing number of studies have found that children get less sleep than previous generations had and experience more sleeping difficulties. New research has found a significant relationship between exposure to television and sleeping difficulties in different age groups, ranging from infants to adults. The number of hours of television watched per day was independently associated with both irregular nap-time and bedtime schedules.
Moreover, passive exposure to TV of more than two hours per day was strongly related to sleep disturbances. TV viewing, particularly passive TV exposures, significantly increase the risk of sleeping difficulties. On the other hand, those adolescents who reduced their television viewing from one hour or longer to less than one hour per day experienced a significant reduction in risk for subsequent sleep problems.
The implications may be serious. Studies have shown that lack of sleep can significantly alter levels of the hormone melatonin, an extremely powerful antioxidant. Reduced amounts of melatonin may result in a greater chance that the cell DNA will produce cancer-causing mutations.
Melatonin also causes sleepiness. As it grows dark, the melatonin levels rise and help facilitate sleep. Researchers have reported that exposure to a television screen was associated with lower urinary melatonin levels, particularly affecting younger children at a pubertal stage when important changes in melatonin’s role take place.
Research from as far as China and Mexico is increasingly identifying television exposure as an independent factor in obesity. Mexico’s health ministry has reported that obesity has risen by 170 per cent in a single decade, with odd ratios of obesity, 12 per cent higher for each hour of television watched per day. While in China, a study of 10,000 people found that for each hour of television viewing, there was a significant increase in the prevalence of obesity. A study in New Zealand following children from birth to 15 years recently found the amount of television viewing to be a more significant factor in obesity than the effect sizes often reported for nutritional intake and physical activity.
Beyond displacing physical activity, a new study has reported a significant dose-response relationship in which the resting metabolic rate [REE] decreased as average weekly hours of TV viewing increased.
One of the mechanisms by which television may induce us to eat more is through causing our brain to monitor external non-food cues – the television screen – as opposed to internal food cues telling us that we have eaten enough and can stop. Experiments have found that when distracted in this way humans continue to salivate unnaturally in response to more and more food when normally they would not. All of these observations occur at a time in our history when 75 per cent of dinners are eaten in front of the television.
A 26-year study of the association between child and adolescent television viewing and adult healthy nvolving 1,000 children recently published in the journal The Lancet, found that children who watched more than two hours of television a day between the ages of five and 15 developed significant health risks many years later. The study concluded that 15 per cent of cases of raised blood cholesterol, 17 per cent obesity, 17 per cent of smoking and 15 per cent of reduced cardiovascular fitness were linked to television viewing that took place years before when the adults were children. This link remained, irrespective of other factors such as social background, body mass index (BMI) at age five, parents’ BMI, parental smoking and the physical activity of children by the age of 15.
Other biological changes strongly associated with watching television range from a clinically increased risk of abnormal glucose metabolism and new type two diabetes in adults, through substantial increases in myopia (short sightedness), to increases in migration of coetaneous immune system mast cells which also lost their granular content and the cytoplasm shrunk.
Watching television, irrespective of the content, is increasingly associated with unfavorable biological and cognitive changes.
These alterations occur at viewing levels far below the population norm. Given the population’s sheer exposure time to this environmental factor it is more than puzzling to consider how little awareness and action has resulted.
Perhaps because television is not a dangerous substance or a visibly risky activity, it has eluded the scrutiny that other health issues attract. Additionally, there is little attention being paid in looking for the negative effects of the world’s favourite pastime.
Conversely, when research is directed at identifying what is termed “opportunities in the media-rich home” and methods to increase so-called “media literacy” or “visual literacy”, encouragement and funding appear highly forthcoming. Therefore, it is hardly surprising that the incriminating research concerning screen media is coming from beyond the domains of media studies, education and psychology.
Television is something that is widely recognized as being so influential and potentially dangerous, but has resulted in so little effective action. To be sure, there has been some lack of political will to take on the enormously powerful and influential entertainment industry to be recognized as a major public health issue”. The biological sciences are instrumental in providing an alternative account of the influence of screen media. By ignoring these observations, findings may ultimately be responsible for the greatest health scandal of our time.