Narrator: This is Science Today. What were you doing the afternoon of March 8th 1996? Unless this date has a particular significance to you, you probably have no idea. That's normal. But there are some people with a superior type of memory called hyperthymesia who could tell you not only what day of the week that was; but what they did, who they were with and what they ate. Neuroscientist James McGaugh of the University of California, Irvine is co-leading a study of people with this unforgettable type of memory.
McGaugh: We have personal information about each of them that we use to make a test about their personal life. So we can ask, what happened on a particular date, and I know what happened because I have information that they went to a concert let's say, on that day.
Narrator: McGaugh says the three subjects they've studied have similar personal characteristics.
McGaugh: They, so far, are all left-handed. We don't know what that means and they are massive collectors of items, of mementos, of things that they owned and they collect lots of them - to a degree which is much more than most people. And all of these may be clues and we intend to find out.
Narrator: For Science Today, I'm Larissa Branin.