‘Ban under-threes from watching television, says study.’ This is how the Guardian reported the findings of a recent article – ‘Time for a View on Screen Time’ by Aric Sigman – that reviews evidence on the effects on physical and mental health of watching television and using computers.

Articles like this – that grab attention by tickling the guilt to which so many parents are susceptible – always annoy me. It often turns out that the scientific research arrives at much more qualified conclusions than the journalist allows. And in any case the possibility that there might be considerable disagreement on the issue in question – among scientists – is not always made clear.

Here, though, the summary appears to be broadly accurate, helped by the fact that the original paper ends with specific recommendations. Furthermore it quotes Dorothy Bishop, a professor of developmental neuropsychology at Oxford University, who argues that Sigman’s paper is not ‘an impartial expert review of evidence for effects on health and child development’ and points out that Sigman ‘does not appear to have any academic or clinical position, or to have done any original research on this topic.’ Most importantly of all: ‘His comments about impact of screen time on brain development and empathy seem speculative in my opinion, and the arguments that he makes could equally well be used to conclude that children should not read books.’

Some of these remarks are beside the point. The article doesn’t claim to be anything more than a summary of existing research, and the author’s ability to do this is surely not dependent on holding an academic or clinical position. But, as reported, the article does seem insufficiently aware of an obvious objection: we know that long periods of physical inactivity are probably not good for you, especially if it was not accompanied by social interaction. Surely it is this, rather than specifically ‘screen time’, that would help to account for increasing obesity and heart problems in children or their compromised intellectual and emotional development.

But what is also problematic (and this is my main concern here) is the assumption that ‘screen time’ is incompatible with physical activity and social interaction. It seems to me that ‘screen time’ covers a highly diverse range of activities – watching televisio; playing games; solving puzzles; following instructions; listening to music; conducting conversations via text, email, messaging or social media; reading and writing anything from status updates to full-length books; making video calls; editing and mixing sounds and images; and so on.

Furthermore, even the traditionally most passive of these – watching television on your own without the ability to change channels or adjust the volume – is often far from mindless consumption. When I walk in on my five-year-old watching a programme, the chances are that he’s commenting out loud on the action, anticipating dialogue, answering questions, expressing surprise or delight, laughing, belting out a song that is playing or – in the case of Tree Fu Tom – standing up, striking poses and trying out moves in imitation of someone on screen. And once I’ve joined him, he’ll ask me things, or draw my attention to something that is happening or about to happen. Sometimes we’ll laugh together in appreciation or pour scorn on something badly executed.

I was intrigued enough to read Sigman’s original paper. Could it really be so uninterested in the nuances and variety of so-called ‘screen time’? It would appear so. I even checked out two or three primary research papers that he cites, curious about the methods they used. Typically, data about ‘screen time’ seems to be collected by asking individuals (or their parents) to complete diaries or questionnaires indicating the number of hours they spend watching television or using computers each day. Thus:

The average time spent each day (weekdays and weekend days combined) in screen time (TV, video, computer, and video game usage) was assessed from parent-reported values. Time spent watching TV was defined as minutes spent watching TV, videotapes, or DVDs. Computer use was defined as minutes spent using a home computer or video game. Screen time was computed by summing minutes spent in TV viewing and computer use. (‘Associations between sedentary behavior and blood pressure in young children’, p726)

In at least one case this data was derived from devices attached to participants’ televisions and computers which would record when they were in use, together with a programme of incentives to ensure different levels of usage in the groups being compared. This is worth quoting at length, as it requires a degree of domestic surveillance that takes us into the realm of dystopian science fiction:

After completing a telephone screen, families attended an orientation, and, if interested, parents read and signed the informed consent and then completed a questionnaire that assessed the numbers of televisions, television video game units, VCR and DVD players, and computers in the home. Approximately 1 week later, a TV Allowance was attached to each television and computer monitor in the home by a research assistant […] who recorded the numbers of televisions and computers and their locations in the home. The TV Allowance is an automated device that controls and monitors the use of televisions or computer monitors, including television, video game systems, DVD players, VCRs, and computers. The appliance was plugged into the TV Allowance, the plug was locked in, and the device was plugged into the wall. To turn on the television or computer monitor, each family member used an individually selected 4-digit code. To protect against the participating child watching television or playing a computer game on other family members’ time, the participating child was not informed of the codes of other family members. If the child learned the codes of another family member, these codes were changed. The TV Allowance sums the minutes of use for each code to objectively determine use of that device.

Baseline television and computer use was measured during a 3-week period. Seventy families met eligibility criteria and were randomized into intervention and control groups [….] Families were recruited in cohorts, were stratified by child sex, and were randomized by the study statistician […] in blocks of 2 without replacement using a random number generator limited to 2 numbers. Group assignments were provided to the project coordinator [….]

Study staff [… ] set the weekly time budgets for television viewing, computer use, and associated behaviors. Budgets were reduced by 10% of their baseline amount per month for children in the intervention group until the budget was reduced by 50%. When the budget was reached, the television or computer monitor could not be turned on for the remainder of the week. Study staff could set different amounts of time for each child in a household, if desired, to reduce conflict if another child was not on the program. Parents and non-participating family members could use their code to watch television or to use computers without being on a budget.

Children in the intervention group earned $0.25 for each half hour under budget, up to $2.00 per week. Parents were instructed to praise the participating child for reducing television viewing and for engaging in alternative behaviors. Decreases were also reinforced by a star chart. At each home visit, a study staff member reviewed the star chart and praised the child for the number of stickers earned. When the child reached the 50% decrease at 6 months, the star charts were discontinued, and changes were supported through monthly newsletters and by parental praise for behavior change. The intervention group received ideas for alternatives to sedentary behavior, a tailored monthly newsletter with parenting tips to reduce sedentary behavior, and information about how to rearrange the home environment to reduce access to sedentary behavior. Children in the control group were provided free access to television and computers and received $2.00 per week for participating, independent of their behavior change. Control families received a newsletter to provide parenting tips, sample praise statements, and child-appropriate activities and recipes. (‘A randomized trial of the effects of reducing television viewing and computer use on body mass index in young children’, p240).

But as far as I could tell, no tests made any distinctions finer than that between one electronic device and another.

Why collect such bland information? It is as if one set up controlled clinical trials to establish whether eating sandwiches was bad for you, or swallowing pills, or going out at night. It is of course perfectly possible that, after quantifying this data, you find that doing more of one thing was probably doing you more harm than less, and to recommend that we cut down on one or other of them. But – even if we accepted the results of these tests – we might think, before making recommendations, to investigate whether it was certain types of sandwiches (with high levels of salt, sugar or saturated fat, for example) that was the main case of harm and if so it might be more effective to recommend reducing our consumption of these sandwiches rather than others. And of course the dangers of going out at night must depend a great deal on what you do: attend an evening class, cycle on busy roads, play bingo, babysit for a friend, deal drugs, or drink alcohol and smoke solidly for twelve hours.

So why don’t these finer distinctions come into play here? One reason must be that it is much harder to quantify ways of watching television or using computers, as opposed to simply calculating the time spent engaged in these activites. Having resolved to model one’s research on clinical trials, the appropriateness of this mathematical model is taken for granted, even though it just may not be possible to make the distinctions thought necessary.

But another reason must be the fairly widespread – but hardly ‘scientific’ – antipathy towards television and its successors, an antipathy that is directed at an easily identifiable target – a product or an industry – that feeds on a simplistic moral division that sets technology against apparently more wholesome forms of activity such as reading and social interaction, a rhetoric that dominates Sigman’s article. Researchers more wary of this ‘common sense’ might have devised methods that tested these assumptions more thoroughly, and Sigman might have challenged them to do so.

The problem here is that both reading, painting, writing, social interaction are not distinct from ‘screen time’ but overlap with it. Many people now prefer to read ebooks than bound books; a good deal of creative design is now accomplished on a laptop rather than with paper, pens and brushes. Social media are so-called because of the, er, social interaction they permit (and demand certain standards of etiquette), although what they herald is the possibllity of increasingly polyphonic conversations already implicit in email, sms and instant messaging services which were originally largely one-to-one.

Until we can find ways of identifying different ways of engaging with computers and televisions and mapping these against certain standards of physical and mental health, we are not likely to learn very much.