Consider the brain as a nightclub.
Is it more important to have a selective bouncer or a huge nightclub?
That’s a question University researcher Ed Vogel proposed.
In 2005, University researchers found that the brain’s filter plays an important role in how much people can think about at once – three or four things, on average. The University’s ongoing research on working memory has helped prompt follow-up research on the topic and has recently spurred more discussion on the topic in the online scientific community, including the Scientific American Community blog. Although University researchers found strong evidence that the brain’s filtering mechanism plays a large role in determining working memory capacity, others say the brain’s capacity still plays a vital part.
Vogel, an associate professor of psychology, said he compares the brain’s filter to an e-mail inbox that filters out unwanted messages and information.
For the past 60 years or so, the scientific community thought that cognitive ability was directly related to the brain’s capacity, Vogel said.
“It’s just how you use that space,” he said.
University researchers measured electrical activity produced in the brain from electrodes placed on the scalp, Vogel said. Subjects were usually University undergraduate students who agreed to participate in the study.
Vogel said he found a direct correlation to those who had a high capacity and intelligence.
“A person with a high capacity tends to do well with mathematics and abstract reasoning,” he said.
High capacity subjects usually had better filtering abilities, according to the paper published in Nature in 2005.
“We found that low-capacity subjects often held more information in their memory – it was just the wrong stuff,” Vogel said.
The research published in Nature propelled other scientists to look into the topic. A new study found what part of the brain is involved in the filtering process.
Researchers at the Stockholm Brain Institute recorded brain activity using magnetic resonance imaging and found that the basal ganglia and the prefrontal cortex were involved in working memory tasks.
Study participants were asked to filter out irrelevant information while looking at objects on a computer screen.
“This work ties together work we’ve done, and we’re trying to give it a good sense of what it all means – what these differences are between all of us,” Vogel said, adding that it’s fascinating that the basal ganglia played a role in the filtering process. “What’s interesting about that is that even though this is an ancient structure, it’s playing a significant role in terms of what we often think of as unique human abilities.”
Nelson Cowan, the director of the Working-Memory Laboratory at the University of Missouri, said that both filtering and the brain’s capacity play in role in working memory.
“I’m not arguing against such a (filtering) mechanism, but I believe you also have to consider that individuals differ in basic capacity,” Cowan said.
He said capacity affects working memory.
In the Missouri lab, he found that the storage capacity and the filtering efficiency of working memory were both related and distinct, he wrote in the Scientific American blog.
If filtering does play the bigger role, however, it’s possible the brain can be trained.
“It opens up the possibility that brain activity can be enhanced or trained,” said Andrew McCollough, a University graduate student involved in the 2005 study.
MRI tests and measuring electrical activity and behavior will all be involved to discover more about working memory, Cowan said.
“This is one area where there’s really healthy interchange, and all of our research working in all of these different methods will play a role,” he said.
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