Bill Gates in response to a question about whether improving health in poor countries will lead to a population explosion: When the Gates Foundation started out, it emphasized "reproductive health," a.k.a. population control. (Someone once noted that you can always convince poor people that rich people have too much money and rich people that poor people have too many children.) But they soon discovered that there's a direct relationship between improving health and slowing population growth. The most effective way to get people to have fewer children is to rapidly improve the health prospects of those kids. Speed is important, because it gives parents a chance to react and have smaller families.


Oliver Sacks: 10% of visually impaired people have visual hallucinations called Charles Bonet Syndrome but only 1% ask their doctors about them--for fear of being thought crazy. Since aging leads to diminished eyesight, these hallucinations are particularly common among the old. But these hallucinations aren't like psychotic hallucinations. They don't engage the emotions and feel like a silent movie. Many involve faces, almost always unfamiliar and often with distorted eyes or teeth. Many others are cartoons. Some are simply geometric shapes--colored squares or triangles rising from the floor, for instance. Sacks himself, who is blind in one eye, has this last type.

Nina Jablonski: Dermatologists have done a good job of warning pale people (like me) that we'd better wear sunscreen if we live in sunny climates. But too little attention has been paid to what happens when dark-skinned people live in northern latitudes or spend their days working indoors. Even moderately pigmented people like Barack Obama are at risk for vitamin D deficiency if they have desk jobs. So we should hope the president takes vitamin D supplements. (Jablonski, a Penn State anthropologist, is the author of Skin: A Natural History.)

Hans Rosling, picking up a long stick and pointing at the screen: "I have solidified the laser pointer." (Rosling's 2006 talk here is one of the most popular Ted.com videos.)

Louise Fresco, on Wonder Bread: "Don't despise the white bread. It symbolizes the fact that bread and food have become affordable to all."

Thousands of Chinese students shouting in unison: "I will learn perfect English." (In a video shown by Jay Walker.)

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