Watching television relaxes you. The almost undetectable screen flicker is a perfect mechanism for lowering our brain waves into the alpha state, the condition we're going for when we meditate. This is why it's so effective for calming an agitated or over-stimulated kid. It's so effective that even those who watch very little TV, and are therefore "unconditioned," are put into that state in 3 minutes or less. It's why so many parents, over decades now, have used "TV time" as a euphemism for "peace and quiet."
But as we all know, there's a price to pay for this shortcut to deep relaxation, just as there is with every shortcut ever devised. We all already know about the opportunity cost of watching TV, all that time spent sitting indoors instead of being outside getting exercise, which has lead in an almost straight line to an epidemic of obesity and diabetes. And most of us are pretty attuned to the fact that advertisers are using the highest powered persuasive techniques ever devised to brainwash our children, and take measures to counteract that. But I'm surprised at how many parents are dismissive about what TV does to our brains.
In college (30+ years ago) we were already talking in our journalism classes about the narcotizing effects of television. It's a real thing. I'm not saying that you should keep your child away from TV, but you need to know, it's no different than putting them on drugs. It's an effective, but not a harmless way to buy yourself a little peace and quiet.
So what exactly does happen to our children's brains as they watch TV?
For one thing, from almost the moment the pictures start to flicker, brain activity shifts from the left side of our brains (the part of our brains responsible for logical analysis and critical thought) to the right side. This means that there is little or no critical analysis taking place, opening their brains to a suggestible, hypnotic state. When we say that watching television is a "passive activity," it is true in a very real sense: scientists detect almost no beta waves at all in TV viewers, indicated no active involvement in or response to what we are watching.
TV is a physical addiction. It causes the brain to release those feel good chemicals called endorphins, morphine like substances created from within the body, and like all opiates, endorphins are highly addictive.
When you watch television your higher brain regions (like the mid-brain and the neo-cortex) simply shut down, leaving you with what is sometimes referred to as the reptilian brain. Studies show that over use of this fight-or-flight part of our brain leads to atrophy of the parts of our brain used for higher functions making us, to use the technical term, stupider.
Our brains, like our muscles, need to be "exercised" in order to remain healthy. The more one watches TV, the less exercise our brains get. Just as lack of physical exercise is known to lead to countless health issues as we get older, lack of mental exercise has been linked to an increased likelihood of being diagnosed with ADHD and other attention disorders, as well as dementia and Alzheimers later in life. (Not to mention the physical risks of heart disease, stroke, and cancer that result from too much sedentary time in front of the boob tube.)
And like with the use of drugs and alcohol, this narcotic of television is particularly dangerous when consumed by children given that their brains are not fully developed.
I know, what a bummer on a summer Saturday, but you know what? It's summer! It's Saturday! Get outside and play! Studies also show that children who play outdoors laugh 20 times more than their indoor, TV watching counterparts, and that's got to be better than quiet time.
Update: I've written a follow-up to this post entitled I Don't Know What It Means, But It's True, in which I address many of the comments and questions from readers. I've also included links to reference materials used to write this post.