Remember..... and Forget

THE SCIENCE OF MEMORY

- Rebecca Rupp

All creatures, from the banana-buzzing fruit fly to the great blue whale, have some form of memory. Elephants remember the locations of distant watering holes. Mice remember how to find their way through laboratory mazes to food. And squirrels, who bury up to 10,000 nuts every year, remember-most of the time where they put them. Crows remember human faces. So, beware: If you're ever mean to a crow, they'll likely remember you.

Of all the memories in the animal kingdom, though, yours is especially impressive.

Each human brain contains about 90 billion neurons-and each of these can form more than a thousand connections with other neurons. Memories are stored in these connections, called synapses. This all adds up, scientists estimate, to more than 60 trillion connections, 2.5 million gigabytes (GB) of memory. (You've got your computer beat-a typical laptop may have eight GB of working memory plus another 256 GB of storage space.) That's right, your memory is huge. If it worked like a computer's hard drive, it would be large enough to store the information from five billion books, 670 million webpages, or 350 years' worth of television shows or films.

Short, Long, and In-Between

Scientists generally divide memory into two major types, short-term and long-term. All information-from the colors of the rainbow to your best friend's telephone number-first enter your memory through a holding pen called short-term memory. Short-term memory is just that, short. It only lasts around 30 seconds, and you can't put much in it. Studies show that short-term memory can only hold about seven pieces of information at a time.

Short-term memory is also easily disrupted. An interruption-say, a dog's bark or a phone's beep-can knock the information in short-term memory right out of your head.