Boost Memory While You Sleep
In this era of multitasking, idle time has become increasingly archaic. We're always plugged in, carrying cell phones on hikes and laptops on cruises, always ready to do several things at once. Even so, one area of life has remained somewhat untouched by the pressure to get productive -- and that's been sleep time. Now, though, scientists have found a way to boost productivity even during sleep.
Researchers at Northwestern University recruited 12 subjects who completed exercises in which they dragged 50 objects to various randomly assigned areas on a computer screen. Whenever the subject moved an object, a corresponding sound played -- a cat meowed while it was dragged, for instance, or a wine glass shattered. The subjects repeated the exercise a few times to learn the correct location for each object. Then, they waited 45 minutes and went to an adjoining, darkened room and took a nap.
While the subjects slept, they wore electrodes attached to their scalps. The resulting EEG readout told the researchers when the subjects fell into deep sleep, at which point the researchers quietly played back 25 of the sounds that had been associated with the moving images. The subjects didn't rouse as the sounds played back and, in fact, none remembered hearing the sounds when they woke up.
Sure enough, upon awakening, the subjects correctly remembered the locations of the objects associated with the sounds played while they slept, but they didn't do as well remembering the correct locations of the other objects.
Study coauthor John Rudoy said, "The research strongly suggests that we don't shut down our minds during deep sleep. Rather this is an important time for consolidating memories." His colleague and coauthor Dr. Ken Paller, explained, "The thinking is that during sleep, memory consolidation is going on and that rehearsal is a good way to strengthen memories. We showed that you can get information in during sleep using the auditory system and that you can cue that rehearsal by providing sounds specific to each episode of learning."
In other words, the sound triggered a constellation of memories associated with that sound -- in this case, a memory of a picture and of a spatial task. According to neuroscientist Dr. Robert Stickgold of Harvard University, "It's not really that you reminded the subjects of what they needed to know, but rather you reminded them of a larger memory that they needed to know."
The news excited researchers who right away saw the possibility that nighttime programming tapes might work, after all. Students might improve SAT scores overnight, they suggested, or learn a foreign language while under the covers. In fact, study coauthor Joel Voss suggested that the process might even work in reverse. "Can memories be distorted as well as strengthened?" he wondered. "Can people be guided to forget unwanted memories?"
This isn't the first study indicating that memory can be manipulated during sleep. A 2007 study exposed card players to a rose scent while they played. Later, while the players slept, some of them were given whiffs of the rose scent. Those who smelled roses overnight subsequently did a lot better on tests asking them to recall card pairs. The different and exciting factor in the new study is that it showed a way to stimulate particular, selected memories, and this is the first research to show that effect.
"Auditory stimuli have the advantage that they can be very specifically linked to visual stimuli," says Dr. Jan Born, a sleep researcher from the University of Lübeck in Germany. "With odors, this kind of thing is not possible.
The thing that keeps getting clearer as sleep studies pile up is that during sleep, memories get "cemented" into our brains. You need a good night's sleep to assimilate memories of any sort, for your brain to assign memories space and to store them. Previous research has suggested that during periods of rapid learning of new tasks, such as during infancy, humans need more sleep to allow for the memory of new tasks learned to be assimilated and stored. At any time of life, though, if you don't get enough sleep, you won't assimilate memories as well and you'll have a harder time retaining learning.
Scientists have suggested that sleep may have special significance for stroke survivors and those with brain injuries. Sleep programming certainly holds promise for those with particular cognitive deficits, who perhaps can program themselves during sleep to regain lost skills, but what about for those normal people who simply want a shortcut to learning?
While it's exciting to think that maybe we can learn effortlessly while we snooze, the question the scientists aren't asking is this: might programming ourselves to learn during sleep disrupt the normal function of sleep and create psychological issues? Does "sleep learning" interfere with the natural processing the brain needs to undergo during sleep so that we achieve optimal health and restoration? Is it really beneficial to go to school 24 hours a day, to be on the information highway even while dreaming? Isn't rest meant to be just that -- rest? Maybe yes, maybe no. But surely, it's a question worth asking before we assault our one last refuge from multi-tasking. On the other hand, for more advanced information on neural enhancement and accelerated sleep learning, check out the Flanagan Neurophone.