"I always explain to people [that it's] like I'm walking around with a video camera on my shoulder and every day is a videotape," Price told ABC News last year. "So if you throw a date out at me, it's as if I pulled the videotape out, put it in the VCR and just watched the day as it happened, like from my point of view."
Doctors are just beginning to observe, let alone understand, this phenomenon.
"First, three of our four top subjects are left-handed, and our fourth has strong tendencies to be left-handed [but] uses a right hand in writing," said McGaugh. "They all have slightly obsessive tendencies. They save a lot of things. They keep a lot of things. Salvation Army will never get rich off these people because they keep it, and so they covet collections the way they covet their memories. We find that interesting."
Also, it turns out certain parts of the super-autobiographical memory subjects' brains are larger than they are in people who don't have super-autobiographical memory. Also, their potential to store information appears infinite.
"There's no capacity limitation on what we can learn," said McGaugh, "no limit to our capacity to learn."
The remembering also is completely unintentional.
Petrella remembers schoolboy sports events in Pennsylvania and that he got glasses in 1956. He remembers all but two of his birthdays since he turned 5. He recalls where he was and what he did with high school buddies. Grainy images of the 1970s are vivid pictures in his head.
"I remember all my ATM codes," he said. "I remember people's numbers. [I] lost my cell phone Sept. 24, 2006. A lot of people, if they lost their cell phone, they would panic because they have all these numbers. I didn't have any numbers in my cell phone because I know everybody's numbers up here [in my head]."
"It's like a hard drive," he said. "You want to throw some of these dates in the trash and put more, maybe some creative things on -- because they are some inane things, a lot of things. Sometimes that's a bad thing, because when I am going through ... a bad situation or a bad circumstance. And then I go back and I go, 'boy, this is how I felt on, say, May 3, 1986."
At the same time, Petrella has the kind of forgetfulness anyone can have. He'll walk into another room and forget why he entered. Or he'll forget that he left his car in a tow zone.
Petrella is most astounding at sports events. If shown a freeze frame from a game 35 years ago, he'll recall details of the sporting event.
And he knows just about everything when it comes to his beloved Pittsburgh Steelers.
"Oh, that was my most memorable Super Bowl," he said when asked about the Steelers' third Super Bowl win. "Jan. 21, 1979, 35-31, over Dallas. Terry Bradshaw was the most valuable player. Threw for 318 yards and four touchdowns."