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 these three subjects have some personal characteristics that are similar.
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.