EVANSTON, Ill. --- You know the feeling. You make a decision you're certain is merely a "lucky guess."
A new study from Northwestern University offers precise electrophysiological evidence that such decisions may sometimes not be guesswork after all.
The research utilizes the latest brain-reading technology to point to the surprising accuracy of memories that can't be consciously accessed.
During a special recognition test, guesses turned out to be as accurate or more accurate than when study participants thought they consciously remembered.
"We may actually know more than we think we know in everyday situations, too," said Ken Paller, professor of psychology at Northwestern. "Unconscious memory may come into play, for example, in recognizing the face of a perpetrator of a crime or the correct answer on a test. Or the choice from a horde of consumer products may be driven by memories that are quite alive on an unconscious level."
The study links lucky guesses to valid memories and suggests that people need to be more receptive to multiple types of knowledge, Paller said.
Paller and Joel L. Voss, who received his Ph.D. at Northwestern and is now at the Beckman Institute, are co-investigators of the study. "An Electrophysiological Signature of Unconscious Recognition Memory" will be published online Feb. 8 by the journal Nature Neuroscience.
During the first part of the memory test, study participants were shown a series of colorful kaleidoscope images that flashed on a computer screen. Half of the images were viewed with full attention as participants tried to memorize them.
While viewing each of the other images, they heard a spoken number, such as 3, 8 or 4, which they had to keep in mind until the next trial, when they indicated whether it was odd or even. On every trial they had to listen to a new number and press a button to complete the number task.
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