The average American child spends three to five hours a day watching TV. In 1961, the average child began to watch television at age three; however, today it is nine months. Yet, most parents think that television has a bad influence on their children. For example, in the early 1970s, my parents believed that my bad eyesight was the result of sitting too close to the screen, and they therefore made my stay at least six feet from it. Today, most people have no such worry, but many new ridiculous (荒谬的) sayings have appeared:

TV makes kids stupid. Many children watch more educational programmes when they are pre-schoolers. When they grow up, they can read more books and have much better ideas to solve difficult problems than other children.

TV makes kids violent. The real story is not so simple. Hundreds of studies show that watching violence on TV makes children more aggressive (好斗的). But a study of over 5,000 children also finds that some positive programmes make children kinder. The problem is that kids are increasingly watching shows with violence instead of those suitable for their age.

Sitting around watching TV makes kids overweight. An experiment finds that when children watch less television, they do lose extra weight; however, reducing their television time does not make them more active. The real problem lies in snacking (吃小吃) — a widespread habit for kids, and junk food advertisements.

TV helps kids get to sleep. The opposite is true. The more television children watch, the more likely they are to have irregular sleep and nap (小睡) patterns. Allowing kids to watch television is part of the problem, not the solution.

On December 26, 2004, hundreds of tourists relaxed on Sri Lanka’s Yala National Park’s beaches. But at mid-morning the park’s elephants began crying wildly and running away from the ocean and up a nearby hill. The puzzled keepers could tell the animals were worried about something but what?

What the keepers did not know was that a 30-foot wall of water was headed straight toward them. This tsunami(海啸) had been caused by an earthquake more than 1, 000 miles away in the Indian Ocean. When the huge wave hit the coast, it caused severe damage. Many people died. The elephants, however, were not swept away by the water. They stood safely on the hill.

Scientists have long suspected that animals sense natural disasters before humans do. People have told stories of dogs refusing to go outside and sharks swimming to deeper waters before a hurricane. After the 2004 tsunami, people said they saw tigers, monkeys, and water buffalo escaping to higher ground before the waters rushed in. Even in the hardest-hit areas of southern Asia, there were few animal deaths.

It's unlikely that an animal’s so-called sixth sense comes from some magical power to see into the future. Experts believe that animals may be more sensitive than humans to changes in temperature and other environmental conditions that take place before a natural disaster. The elephants in Sri Lanka, for example, may have picked up vibrations from within the Earth, a sign that earthquake was coming. Because vibrations in the ground travel much faster than an ocean wave, the elephants may have felt the earthquake that caused the tsunami well before the tsunami itself came to the coast.

A few scientists are calling for a system to track reports of strange behavior in people’s pets, hoping that these reports can serve as a warning system that a natural disaster is about to happen. But Marina Haynes, an animal behavior scientist at the Philadelphia Zoo, says, “It would be an unreliable way to predict disasters. It can be difficult to know what an animal is doing. Is the animal nervous because an earthquake is about to happen or is it frightened because there is an enemy nearby?”