The study by Edward Vogel, at the University of Oregon, is the first to demonstrate that awareness, or "visual working memory," depends on 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 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."

Source: University of Oregon, 2005


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