March 2009 - Research from Northwestern University published online in Nature Neuroscience
offers electrophysiological evidence that decisions thought to be based on guesswork or 'gut feelings' may actually draw on valid memories that cannot be consciously accessed. Researchers conclude that people should be more receptive to different types of knowledge.
Ken Paller, professor of psychology said:
"We may actually know more than we think we know in everyday situations, too. 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."
Study participants in two groups of 24 were shown a series of colorful kaleidoscope images that flashed on a computer screen. In 50 per cent of examples they were asked to give full attention to trying to memorize the image. The second group of images were associated with a spoken number which participants were asked to remember until the next trial, when they pressed a button to indicate whether it was odd or even. A new number was given in every trial. Researchers explain that while participants could focus on memorising half the images, the study design greatly distracted them from memorizing the others. A short time later, participants viewed pairs of similar kaleidoscope images in a recognition test.
Ken Paller commented:
"Remarkably, people were more accurate in selecting the old image when they had been distracted than when they had paid full attention. They also were more accurate when they claimed to be guessing than when they registered some familiarity for the image. Splitting attention during a memory test usually makes memory worse ...But our research showed that even when people weren't paying as much attention, their visual system was storing information quite well."
EEG signals recorded from a set of electrodes on 12 participants' heads identified different brain waves when implicit recognition occurred compared with results associated with conscious memory experiences. A unique signal was seen one-quarter of a second after participants saw each old image.
Ken Paller said:
"The novel results show that when people try to remember, they can know more than they think they know."
The current research builds on previous studies showing that amnesia victims often have strong implicit memories and cautions against sole reliance on conscious memory.
Ken Paller concluded:
"It suggests that we also need to develop our intuitive nature and creativity. Intuition may have an important role in finding answers to all sorts of problems in everyday life - including big ones such as our ailing economy."
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