The examples given here involve food. Although this was written to help with fears around tv, movies, and video, the principles fully apply to food, and to other things.
Conclusion: Restricting tv-watching time increases the marginal utility of tv watching and causes children to become extremely strongly attracted to it and to value tv-watching above other, nonrestricted, activities.
"Utility" is a word used by economists to mean the pleasure, satisfaction, usefulness, or whatever other value a person gets from a product or service. Gaining utility is the reason why a person buys a product or engages in an activity. Just like businesses make decisions in such a way as to maximize total profits, individuals make decisions in such a way as to maximize their "total utility." Economists view people as "utility-maximizing" agents. Through an economist's eyes, we're all going through our lives making constant comparisons — choosing minute-by-minute what to do, what to eat, what to buy, what to wear, what to say, and everything else, and every time we choose, we do it so as to increase our total utility as much as possible. Imagine you are standing in an ice cream store and choosing a flavor — what an economist sees is that your brain is rapidly going through all the choices, figuring out how much utility you'd gain from a scoop of strawberry versus a scoop of rocky road and so on, and then picking the one that gives you the most utility. (Notice that utility has to be predicted — we could be wrong in our pick, but we do our best given the information we have. I could decide that strawberry is my pick for today — that's the flavor that I prefer right now — the one that will give me the most utility. And then I might discover, to my dismay, that it doesn't live up to my expectations and I might WISH I could change my mind. It happens. So, our choices are actually based on our "expected" utility gains.)
Okay — there is a lot more I could say about "utility" and if you have objections to this way of seeing the world, we can talk about them. But I'll leave that for later and, after introducing one more idea, I'll move on to what this has to do with children and television-watching restrictions.
First, imagine you're in that ice cream shop and you've bought that strawberry cone because it had a high utility value to you. You eat it up and it is delicious and you compute the expected utility of ANOTHER ice cream cone and decide to buy one. You eat it. YUM. Now you compute the expected utility of a third ice cream cone. So — what do you think? Is the 2nd ice cream cone going to give you as much ADDITIONAL utility as the 1st did? Will the 3rd one be expected to add as much to your total utility as the 1st or 2nd ones did? What's going to happen as you eat more ice cream cones? After you've had one, the expected utility of the next is lower than the expected utility was for the first. And after you've had two, the expected utility for the third will be lower than the expected utility for the second one was. They still might have value to you, they still give you utility, just not as much extra utility.
The "extra" utility you get from having "one more" of something, is
called "marginal utility."
And - marginal utility goes DOWN as you have more and more of the same thing.
Even if you chose different flavors for each of your ice cream cones, you'd have chosen the highest-utility flavor first and so subsequent cones would provide lower and lower marginal utility.
This way of looking at choices is applicable to almost everything we do.
What's your favorite thing to do? Watch movies? Read a book? Garden? Go to Disneyland? Why don't you just do that all the time and nothing else? I mean — if it is your favorite, then doesn't it give you higher utility than anything else? Why do you ever stop doing it?
The answer is that as you do more and more of something, the marginal utility of doing even more of it, goes down. As its marginal utility goes down, other things start to look better and better.
When you restrict an activity, you keep the person at the point where the marginal utility is really high.
When you only allow a limited amount of TV, then the marginal utility of a little more tv is high and every other option looks like a poor one, comparatively. Watching more TV becomes the focus of the person's thinking, since the marginal utility is so high. Relax the constraints and, after a period of adjustment and experimentation to determine accurate marginal utilities, the focus on TV will disappear and it will become just another option.