Sesame Street is best known for the creative geniuses it attracted, people like Jim Henson and Joe Raposo and Frank Oz, who intuitively grasped what it takes to get through to children. They were television's answer to Beatrix Potter or L. Frank Baum or Dr. Seuss. But it is a mistake to think of Sesame Street as a project in a flash of insight. What made the show unusual, in fact, was the extent to which it was exactly the opposite of that – the extent to which the final product was deliberately and painstakingly engineered. Sesame Street was build about a single, breakthrough insight: that if you can hold the attention of children, you can educate them.

This may seem obvious, but it isn't. Many critics of television, to this day, argue that what's dangerous about TV is that it's addictive, that children and even adults watch it like zombies. According to this view, tit is the formal features of television – violence, bright lights, loud and funny noises, quick editing cuts, zooming in and out, exaggerated action, and all the other things we associate with commercial TC – that hold out attention. In other words, we don't have to understand what we are looking at, or absorb what we are seeing, in order to keep watching. That's what many people mean when they say that television is passive. We watch when we are stimulated by all the whizzes and bangs of the medium. And we look away, or turn the channel, when we are bored.

What the pioneering television researchers of the 1960s and 1970s – in particular, Daniel Anderson at the University of Massachusetts – began to realize, however, is that this isn't how preschoolers watch TV at all. "The idea was that kids would sit, stare at the screen, and zone out," said Elizabeth Lorch, a psychologist at Amherst College. "But once we began to look carefully at what children were doing, we found out that short looks were actually more common. There was much more variation. Children didn't just sit and stare. They could divide their attention between a couple of different activities. And they weren't being random. There were predictable influences on what made them look back at the screen, and these were not trivial things, not just flash and dash." Lorch, for instance, once reedited an episode of Sesame Street so that certain key scenes of some of the sketches were out of order. If kids were only interested in flash and dash, that shouldn't have made a difference. The show, after all, still had songs and Muppets and bright colors and action and all the things that make Sesame Street so wonderful. But it did make a difference. The kids stopped watching. If they couldn't make sense of what they were looking at, they weren't going to look at it.