Even if you could get more RAM for your
brain, the extra storage probably wouldn't make it easier
for you to find where you left your car keys.
What may help, according to a discovery published Nov.
24 in the journal Nature, is a better bouncer – as in
the type of bouncer who manages crowd control for nightclubs.
The study by Edward Vogel, an assistant professor of cognitive
neuroscience at the University of Oregon, is the first
to demonstrate that awareness, or "visual working memory,"
depends on your ability to filter out irrelevant information.
"Until now, it's been assumed that people with high capacity
visual working memory had greater storage but actually,
it's about the bouncer – a neural mechanism that controls
what information gets into awareness," Vogel said.
The findings turn upside down the popular concept that
a person's memory capacity, which is strongly related
to intelligence, is solely dependent upon the amount of
information you can cram into your head at one time. These
results have broad implications and may lead to developing
more effective ways to optimize memory as well as improved
diagnosis and treatment of cognitive deficits associated
with attention deficit disorder and schizophrenia.
The study used a new technique for measuring brainwaves,
developed by Vogel and previously reported in Nature (April
2004), which allows researchers to record the effects
as objects pop into the minds of their subjects on a moment-by-moment
basis.
Working with two of his graduate students, Andrew McCollough
and Maro Machizawa, Vogel recorded brain activity as people
performed computer tasks asking them to remember arrays
of colored squares or rectangles. In one experiment, researchers
told subjects to hold in mind two red rectangles and ignore
two blue ones. Without exception, high-capacity individuals
excelled at dismissing blue, but low-capacity individuals
held all of the rectangles in mind.
"People differed systematically, and dramatically, in
their ability to keep irrelevant items out of awareness,"
Vogel said. "This doesn't mean people with low capacity
are cognitively impaired. There may be advantages to having
a lot of seemingly irrelevant information coming to mind.
Being a bit scattered tends to be a trait of highly imaginative
people."
This work was supported by grants from the National Institutes
of Mental Health and the Oregon Medical Research Foundation.
At the University of Oregon since 2001, Vogel leads the
Visual Working Memory and Attention Lab in the Department
of Psychology.
Machizawa assisted with Vogel's research while completing
his master's degree. He is now a researcher at the Riken
Brain Sciences Institute, Japan's leading funding agency
for scientific research.
McCollough, who is working toward his doctorate, is a
graduate research assistant in Vogel's lab.
