You spend a third of your life asleep. Wouldn’t it be great if you could
put that time to use? New research suggests you can. A recent study,
published in Nature Neuroscience, contains groundbreaking findings that
may change the way we view our time in bed. For the first time,
researchers demonstrate that you can learn new information while you
sleep and with no conscious knowledge of it.
Learning while you sleep isn’t a new idea. But while several studies
have shown that you can enhance prior learning during sleep, until now
no studies have shown that you can learn new information during sleep.
One problem with demonstrating new learning in sleep is that you can’t
test for it without waking up the subject.
To skirt this problem, a team of researchers in Israel took advantage
of a reliable and sneaky measurement tool—the nose. The nose is useful
because humans tend to sniff more when a pleasant smell is present, and
less for a bad smell. Sniffing, therefore turns out to be a measurable
and reliable indicator of odor preference. And odor preference can be
used to measure learning.
Add to that the fact that smells don’t tend to wake people up, and
you’ve got a way to measure learning in sleep. The researchers exploited
this and measured the amount of sniffing among subjects in the presence
of various odors, from shampoo to rotten fish. Finding that, indeed,
sleeping subjects sniffed less for rotten fish, they then used sniffing
to measure learning in an ingenious sleep study.
There were 55 subjects in total. After suiting up for an EEG recording
(to ensure that they were actually asleep), subjects went to sleep for
the night. While subjects slept, researchers paired odors with different
auditory tones. One tone might be paired with the smell of shampoo,
another with the smell of rotten fish. Researchers measured the sniff
volume for each tone.
Later on in sleep, and again once the subjects awoke, the researchers
played the tones without presenting the odor. The big finding? The
subjects sniffed as if the odor was present—more for the tones that had
previously been paired with good smells; less for tones associated with
bad smells.
In other words, the subjects learned to associate a tone with an
odor, having no conscious knowledge that they’d been trained. And
importantly, they retained this knowledge upon waking.
While the idea of learning while we sleep has been around forever,
demonstrating it has been another story. With a little ingenuity, these
researchers have made it official. Still, a lot of questions remain. One
of the questions they wish to better address is the role of REM versus
non-REM sleep in learning. Also, the learning they demonstrated—simple
associations—is not rich in immediate practical value.
So what are the limits of what we can learn?
If the learning were more complex, would the new knowledge be
accurate or mixed up? How might this affect quality of sleep? Can
children learn during sleep? The elderly? Could sleep-learning become
psychological therapy for certain disorders or addictions? Treatment for
neurodevelopmental or neurological conditions? Learning disabilities?
The potential usefulness makes this discovery exciting, even if
preliminary.
While it’s not exactly enough to suggest you should play recordings
of that new language you’ve wanted to learn tonight, this study offers a
new research paradigm for studying learning in sleep and opens the door
to other studies to address some of the exciting questions that remain.
It goes to show that we still have a lot to learn about the power of
sleep; not only its importance for our well-being but its unknown range
of potential utility.
Interesting right .
