From: Zuckuss
Subject: I always knew video games were good for scientific research.

Hi everyone, there was this really neat article in the toronto star
today, some of you may have read it but for those who havent here it is.

Tetris helps shape new dream theory

An experiment involving a video game called Tetris, amnesiacs and a
sleep lab has shed dramatic new light on the nature of dreams.

The experiment was conducted by Dr. Robert Stickgold and colleagues in
Boston. Tetris is hugely popular and addictive. Players must rotate and
slide blocks back and forth as they descend on a computer screen. If you
do it well, they fit together at the bottom; otherwise they pile up and
the game is over.

Stickgold's volunteer Tetris players included several severely amnesic
patients, who displayed only marginal improvement over several hours of
play. This isn't surprising; from one day to the next, none could
remember playing the game or even having met the experimenters.

However, the amnesic players shared something with those with intact
memories. Both groups experienced strange dream-like images of the game
just as they were falling asleep. It was this that led Stickgold to
conclude he'd found something important about dreaming.

Here's why. The bizarre visions you sometimes experience when you are
just on the border between wakefulness and sleep are called hypnagogic
images. They have a hallucinatory quality to them and are thought by
dream researchers to be like, if not identical to, the images of dreams.

These images may derive from the day's activities, especially if you
have been working hard at something completely new. That explains why
participants in this experiment relived their Tetris experiences just as
they were falling asleep. But it seems impossible that people with
amnesia - who couldn't even remember playing the game - nevertheless
replayed images of it. Yet they did. A typical report was, ``I just was
trying to figure out those shapes and get them aligned.''

Stickgold thinks they could do it because our brains contain different
memory systems. One, located deep in the brain, is responsible for the
memory of events and experiences. In the amnesiacs, this memory system
had been obliterated by brain damage of one kind or another. That's why
they couldn't remember playing the video game.

But there are other kinds of memory, including a system thought to be
diffusely distributed over the surface of the brain. Rather than
recording people, places and times , this memory contains only fragments
of your experiences. But they are key fragments: essences of memory. As
Stickgold says, ``When you're asked what five plus five is, you say 10;
you don't remember when or where you first learned the answer.'' It's
retained by this second memory system.

This must be the memory system producing the Tetris imagery in the
amnesiacs, because that's the only memory they have left. A little more
than 7 per cent of all their hypnagogic images were Tetris-related. But
oddly, a little more than 7 per cent of the images experienced by the
subjects with intact memories were also Tetris images. Stickgold argues
that this similarity is evidence that all the Tetris imagery had the
same origin, the memory for an event's essence not its circumstances.

For instance, when people, amnesic and not, described their Tetris
images, they never recalled the room, the desk, anything but the shapes
themselves: ``I'm just watching tiles fall down.''

What are the implications of this study? If you accept that these images
appearing on the verge of sleep are the same as dream images, and that
they are supplied by the more iconic memory system, then this study
might be a partial explanation of the strangeness of dreams.

We've all marvelled at the fact that in many dreams, vivid images
connect to each other in the most illogical way (although that doesn't
seem to trouble us during the dream). But according to this study, the
memory system supplying those images retains no trace of the context for
the memory. It's in the business of remembering nuggets of memory and
associating them. Sounds like a dream, doesn't it?

It's no wonder that when we remember our dreams, they seem strange.
We're judging them by the standards of our context event-related memory,
one that demands a sensible progression of events. But that isn't where
they come from.