That anxiety keeps him close to home. He can't drive, rarely goes shopping, and finds the beach a difficult place because of his compulsion to count the grains of sand. And it manifests itself in other ways, like making a very precise measurement of his cereal each morning: it must be exactly 45 grams of porridge, no more, no less.
Daniel was recently profiled in a British documentary called "Brainman." The producers posed a challenge that he could not pass up: Learn a foreign language in a week - and not just any foreign language, but Icelandic, considered to be one of the most difficult languages to learn.
In Iceland, he studied and practiced with a tutor. When the moment of truth came and he appeared on TV live with a host, the host said, "I was amazed. He was responding to our questions. He did understand them very well and I thought that his grammar was very good. We are very proud of our language and that someone is able to speak it after only one week, that's just great."
"Do you think that Daniel, in a certain way, represents a real pathway to further understanding the brain?" Safer asks Dr. Ramachandran.
"I think one could say that time and again in science, something that looks like a curiosity initially often leads to a completely new direction of research," Ramachandran replies. "Sometimes, they provide the golden key. Doesn't always happen. Sometimes it's just mumbo-jumbo. But that may well be true with savants."
Daniel continues to volunteer for scientists who want to understand his amazing brain. But he is reluctant to become what he calls "a performing seal" and has refused most offers to cash in on his remarkable skills.
"People all the time asking me to choose numbers for the lottery. Or to invent a time machine. Or to come up with some great discovery," he explains. "But my abilities are not those that mean that I can do at everything."
But he has written a book about his experiences, entitled "Born on a Blue Day."
He also does motivational speeches for parents of autistic children-yet one more gift of his remarkable brain.
But at the end of the day-genius or not-that brain does work a little differently.
"One hour after we leave today, and I will not remember what you look like. And I will find it difficult to recognize you, if I see you again. I will remember your handkerchief. And I will remember you have four buttons on your sleeve. And I'll remember the type of tie you're wearing. It's the details that I remember," Tammet tells Safer.
And it's the details that make us all so different. One man may see numbers as a tedious necessity of modern life, another sees them as the essence of life.
"Pi is one of the most beautiful things in all the world and if I can share that joy in numbers, if I can share that in some small measure with the world through my writing and through my speaking, then I feel that I will have done something useful," he says.
Produced By Deirdre Naphin
