When you forget a face or can't find your car keys, it's not because your brain is out of storage space. You just aren't filtering out other thoughts well enough, a new study finds.
The research contradicts a popular notion that memory capacity is solely dependent on how much information you can cram into your noggin.
Rather, it shows that if you can disregard some of what you see, you'll do a better job remembering the visual input you deem important.
Researchers measured brainwaves as objects popped into the minds of the test subjects, who watched colored rectangles appear on a computer screen. In one experiment, researchers told the subjects to focus on two red rectangles and ignore two blue ones.
Without exception, one group had all the rectangles in mind, while another group of individuals -- who were already deemed to have high memory capacity -- consistently excelled at dismissing the blue rectangles.
"People differed systematically, and dramatically, in their ability to keep irrelevant items out of awareness," said study leader Edward Vogel of the University of Oregon.
Vogel thinks of this ability to focus as akin to having a thought bouncer in the brain, managing crowd control. The results, detailed in the Nov. 24 issue of the journal Nature, suggest ways to improve memory abilities.
"Being 'scatterbrained' is often a symptom of a hectic modern life in which we are often overcommitted, overworked, and inundated with information," Vogel told LiveScience. "Given such an environment, it would not be surprising if many of our important cognitive control processes become overtaxed and less efficient. Attentional training may be able to improve one's ability to bounce irrelevant information from awareness."
Not that the lack of a bouncer is necessarily bad thing.
"There may be advantages to having a lot of seemingly irrelevant information coming to mind," Vogel points out. "Being a bit scattered tends to be a trait of highly imaginative people."
But for those who would like to do better at keeping track of their thoughts, help might be on the way. Vogel's team is working on focusing drills based on the new research.
Other work by Vogel's University of Oregon colleague Michael Posner has found that five days of attention training helped children develop their memory bouncer and raise scores on general intelligence tests.
"It appears that these functions can be improved through training, at least during childhood," Vogel says. "Interestingly, there has been some recent evidence that similar improvements can also be seen in adults who have been trained on certain video games."