Is there any scientific evidence for TV being intrinsically harmful to children, or is it the loss of what TV replaces that is harmful?

Question

It’s commonly accepted that responsible parents should regulate children’s amount of TV time closely.

Is this because there is something particularly problematic about the actual act of watching television that is problematic?

Or is it rather a problem simply because of what the children might otherwise be doing if not watching TV (e.g. reading, socializing, physical activity, and so on)? Does this imply, for example, that even “large” amounts of TV can be benign if, say, the TV is enjoyed with others (a form of socializing), or is itself educational (a partial replacement for reading)?

For the purposes of this question, let’s assume that any and all material seen on the TV is entirely appropriate for the child’s viewing, and that the parents are aware and involved enough to be monitoring and ensuring this fact. I am particularly interested here in any scientific literature on the subject; any personal stories or anecdotal evidence would have to be very clear-cut and explicit to be of interest to me.

My interest here is in encouraging “careful thinking” with respect to TV. Certainly, we can agree, there are some children who spend “too much” time in front of the TV—but I think it’s important to distinguish between that being inherently bad, and that being bad solely because of what it means they aren’t doing. Is it sufficient to simply limit TV time, or is there an implied assumption that limited TV time implies more time spent on other, more beneficial activities?—and if so, does that mean that parents ought to be not only limiting TV time, but also either providing superior alternatives, or monitoring how a child spends their time away from the TV to make sure the child is actually finding their own alternatives?

Answer 1

Great question. There are several different reasons one might want to limit TV time for kids, and understanding those reasons can help support informed decisions about when --- and how --- to let kids watch TV. There are three potential problems with TV time:

1. TV replaces other activities that may be more valuable
2. Some TV content may not be appropriate for kids
3. There may be negative effects of TV exposure itself

This is an area of on-going research, and all three of these are complex issues, so nothing is cut and dried. I've pulled together a couple resources that might be useful for you, though.

TV replaces other activities that may be more valuable

Many of the bad effects of TV are related to what's not happening during TV watching rather than what is, as you suggest:

Or is it rather a problem simply because of what the children might otherwise be doing if not watching TV (e.g. reading, socializing, physical activity, and so on)?

For example, there is evidence that higher TV watching is associated with health problems such as obesity (citation), but that's likely just because it's a sedentary behavior, not because the TV exposure itself is harmful (i.e. a child who spent at time sitting quietly on the couch not watching anything would probably be at the same risk as a child who spent that time watching TV).

There are also studies showing an association between more TV time and delays in learning to read (citation). In this case, the probable reason for the association is that children who spend more time watching TV spend less time reading, so they're getting less practice and are therefore slower learning than their peers who spend more time reading and less time watching TV. Similarly, more TV time is associated with slower language development, but this relationship can be completely statistically explained (a mediation model) by the amount of language kids hear from adults (study); in other words, the reason kids who watch more TV learn language more slowly is because those kids are hearing less language from their caregivers.

So basically, the risk is that there are only so many hours in the day and the more time you spend watching TV the less is left for other activities. That's potentially a serious concern, because TV watching is an activity with very few positive features (very little physical movement, very little problem solving or reasoning, very little social interaction, etc.).

Some TV content may be harmful for kids to consume

There are also studies showing negative effects of TV content itself, such as possible aggressive behavior, poor body image, substance use, and poor school performance (here is a review, including citations for several supporting studies). In many of these studies, the issue is appropriate content --- kids are watching programs with violence, substance use, sexualization of women, etc. which can influence their thoughts, ideas, and values.

Parents being involved and aware of their children's TV consumption (and setting rules about what is or isn't okay to watch) can prevent many of these issues. So what if you make sure your kid gets lots of time doing healthy activities, and you're careful about them not watching any inappropriate content? Is there still risk associated with TV time?

Negative effects of TV time itself

Even when watching child-appropriate content, there is still some evidence to suggest that more TV time is associated with attention problems later in life (citation). There are also immediate effects of high-energy TV such as cartoons, which make it harder for children to concentrate and reduce their ability to control impulses after watching them (citation). In that study, children were randomly assigned to watch either fast-paced cartoons (Spongebob Squarepants), educational TV (a PBS broadcast about a preschool aged boy), or to color. Right after, the children were measured on a variety of tasks designed to assess executive function skills such as attention, following instructions, and impulse control. Children who had just seen the cartoons showed impaired performance across the board. Children who had watched the slower-paced PBS show showed more or less normal performance, and children who had been coloring showed mostly normal performance with some tasks better than normal. This study illustrates that even among children's programming, some shows may sap cognitive resources while others don't.

So there's evidence that TV can impair cognitive functioning. Can TV still play an important role in education? From the studies that have been conducted on this topic, the answer appears to be, "Maybe for older kids, but not for infants and toddlers under 2." I've already compiled sources on this for my answer to another related question, so I'll just quote the relevant piece here:

This study tests toddlers' ability to learn new words from conversations watched over video compared to in person. This study tests particular videos explicitly marketed to help infants learn (Baby Einstein videos), showing that infants don't actually learn new words from them without significant scaffolding from caregivers. (Here's a review that covers several similar studies, if you want to learn more, and another)

There have also been a few studies testing how well infants can learn a foreign language from exposure to media (video recordings), the most famous of which is probably this study showing infants don't learn much about the sound structure of a foreign language unless they get exposed to it live, in person.

Here is a great review article on evidence about infants' ability (or lack thereof) to learn from TV, including a precise discussion of the special circumstances under which infants do appear to be able to learn from TV exposure. It also contains citations for many more studies on this topic, so if you want to learn more that's a great place to start. Another study investigated circumstances under which 2-year-olds were able to imitate a new skill learned in a video, and found that they could do it under some circumstances but not others.

Older kids (>2yo) and adults definitely can learn things from TV, of course (I've learned plenty of cool things from TV myself). But infants and toddlers really don't, unless you provide a lot of social support for them, watching and discussing the content together (and, at that point, it's hard to say if the child is really learning from the TV program or just learning from you talking about the TV program).

As with any activity, there are both pros and cons --- I'm not suggesting that we should all have a no-TV-ever policy for kids. Watching TV is fun, and it can be a nice opportunity to relax and cuddle. But in order to make decisions you feel good about, it's important to be aware of the risks of TV exposure and the benefits.

Answer 2

LINK According to that link:

• Children who consistently spend more than 4 hours per day watching TV are more likely to be overweight.
• Kids who view violent acts on TV are more likely to show aggressive behavior, and to fear that the world is scary and that something bad
  will happen to them.
• Teens who play violent video games and apps are more likely to be aggressive.
• Characters on TV and in video games often depict risky behaviors, such as smoking and drinking, and also reinforce gender-role and
  racial stereotypes.

That's why it's so important for parents to keep tabs on their kids' screen time and set limits to ensure they're not spending too much time in front of a screen.

There are many sources available as to the pros and cons of watching TV. I think it makes kids have shorter attention spans -- LINK That concerns smartphones -- but tech is tech.

There are many truly excellent programs on TV. Like the internet, it can be a friend or a foe to learning. Use it wisely and it is a plus. I once had a nonverbal student who watched NatGeo Animal Planet with his family and started to make sounds -- copying animals, and it helped lead him to some limited vocabulary.

If I were to advise anyone about TV, I'd say keep it to 2/3 'good' TV -- nature, history, educational and 1/3 sports and pure fun. Watch as a family. Use events in sitcoms and dramas to discuss your family morals and beliefs. TV can help get more difficult conversations going, naturally.

Answer 3

Is there any scientific evidence for TV being intrinsically harmful to children,

I don't know if this will be 'scientific' enough but Strobe lighting effect certainly can be detrimental to children. There was the infamous episode from the Japanese version of the Pokemon anime "Dennō Senshi Porygon" which had such intense strobe lighting effects that nearly a thousand Japanese children had to be taken to the hospital.

Wikipedia tells us the following.

"Dennō Senshi Porygon" (でんのうせんしポリゴン Dennō Senshi Porigon?, translated as "Cyber Soldier Porygon", though more commonly referred to as "Electric Soldier Porygon") aired on TV Tokyo in Japan on December 16, 1997 at 6:30 PM Japan Standard Time.[1] This episode was claimed to be dangerous for health. 20 minutes into the episode, there is a scene in which Pikachu stops some vaccine missiles with its Thunderbolt attack, resulting in a huge explosion that rapidly flashes red and blue lights.[2] Although there were similar parts in the episode with red and blue flashes, an anime technique called "paka paka" made this scene extremely intense,[3] for these flashes were extremely bright strobe lights, with blinks at a rate of about 12 Hz for about 5 seconds in almost fullscreen, and then for 2 seconds outright fullscreen.[4]

At this point, viewers started to complain of blurred vision, headaches, dizziness and nausea.[2][5] A few people even had seizures, blindness, convulsions, and lost consciousness.[2] Japan's Fire Defense Agency reported a total of 685 viewers, 310 boys and 375 girls, were taken to hospitals by ambulances.[2][6][6] Although many victims recovered during the ambulance trip, more than 150 of them were admitted to hospitals.[2][6] Two people remained hospitalized for over 2 weeks.[6] Some other people had seizures when parts of the scene were rebroadcast during news reports on the seizures.[5] Only a small fraction of the 685 children treated were diagnosed with photosensitive epilepsy.[7]

The news of the incident spread quickly through Japan. The following day the television station that had aired the episode, TV Tokyo, issued an apology to the Japanese people, suspended the program, and said it would investigate the cause of the seizures.[2] Officers acting on orders from the National Police Agency questioned the program's producers about the cartoon's contents and production process.[3] The Ministry of Health, Labour and Welfare held an emergency meeting, discussing the case with experts and gathering information from hospitals. The series exited the airwaves.[2]

Later studies showed that 5–10% of the viewers had mild symptoms that did not need hospital treatment.[4] 12,000 children reported mild symptoms of illness, but their symptoms more closely resembled mass hysteria than a grand mal seizure.[2][8] A study following 103 patients over three years after the event found most of them had no further seizures.[9] Scientists believe the flashing lights triggered photosensitive seizures in which visual stimuli like flashing lights can cause altered consciousness. Although about 1 in 4,000 people are susceptible to these types of seizures, the number of people affected by this Pokémon episode was unprecedented.[6]

After the airing of "Dennō Senshi Porygon", the Pokémon anime took a four-month break until it returned on April 16, 1998.[10][11] After the hiatus, the time slot changed from Tuesday to Thursday.[12] The opening theme was also redone, and black screens showing various Pokémon in spotlights were broken up into four images per screen. Before the seizure incident, the opening was originally one Pokémon image per screen.[12] Before the resumption of broadcast, "Problem Inspection Report on Pocket Monster Animated Series" (アニメ ポケットモンスター問題検証報告 Anime Poketto Monsutā Mondai Kenshō Hōkoku?) was shown. Broadcast in Japan on April 11, 1998, host Miyuki Yadama went over the circumstances of the program format and the on-screen advisories at the beginning of animated programs, as well as showing letters and fan drawings sent in by viewers, most of whom were concerned that the incident would lead to the anime being cancelled.[12] The seizures were actually caused by animation errors. After that episode aired, prior episodes with seizure-like effects were edited for rebroadcasting (especially the non-Japanese releases).