GREAT MEMORIZERS

* On July 2, 2005, Akira Haraguchi of Japan recited the first 83,431 decimal places of the number pi from memory, earning a place in the Guinness Book of World Records.

* Kim Peek, inspiration for the movie Rain Man, can recall from memory 7,600 books he has read.

* The Vilna Gaon, an 18th century Jewish scholar, could count from memory the number of times a particular Talmudic sage was mentioned in any book of the Talmud

PICTURE THIS

Imagine how incredible it would be to have a photographic memory. You could memorize anything--pages from a book, phone numbers, baseball stats--just by looking at it for a few seconds! Well, helpful as it might be on your next history test, photographic memory in the usual sense is probably a myth. The closest thing to it is called eidetic (pronounced eyedeh-tick) memory.

Eidetic memory is the ability to remember an image so clearly that it seems real. Eidetikers (people with eidetic memory) can look at a picture and then describe it in detail for a few minutes. They even move their eyes around the nonexistent scene while describing it, as if it were really there. But after a few minutes, the image fades from their minds (or they blink), and it's gone forever.

Between 2 and 10 percent of preadolescents are eidetikers, but eidetic memory fades with age. Less than one in a thousand adults have it, probably because the hippocampus, the part of the brain that forms, sorts, and stores memories, learns to store information in different ways as we grow older. Think about it: If we remembered every minor detail of every day, our brains would become cluttered.

People with excellent memories, eidetic or not, are super efficient at organizing certain kinds of information, often using memory tricks and associations. So, if you want to improve your memory for that history test, organize the information, make word associations, and develop memory tricks for the details.

YOU MUST REMEMBER THIS

Even though eidetic memory can’t be learned, people can improve their memories using mental tricks. Before the volumes of Mishnah and Talmud were written down, they were “oral Torah” and had to be memorized. They were taught from one person to another, often using mnemonic devices (sentences, words, or letters used to help remember). A famous example found in the Pesach Haggadah is D’tzakh A’dash B’ahab, a mnemonic by the second century sage Rabbi Yehudah, that uses the first letter of the names of each of the ten plagues to remember them in order.