Sleep & Memory

Ian Goddard igoddard at
Sat Apr 6 00:14:58 EST 2002

New Reason To "Sleep On It": Study Shows Importance Of Sleep To
Memory Consolidation And Task Performance

Boston, MA (November 21, 2000) -- School kids may be cutting back on
self-defeating strategy. Harvard Medical School researchers have
found that people who stay up all night after learning and
practicing a new task show little improvement in their performance.
And the study suggests that no amount of sleep on the following two

"Our research shows that you need sleep that first night if you want
to improve on a task," says Robert Stickgold, Harvard Medical School
assistant professor of psychiatry at the Massachusetts Mental Health

The study, which appears in the December Nature Neuroscience, adds a
critical piece to a growing body of work by Stickgold and others
showing that sleep is necessary for learning (see

Previously, Stickgold and his colleagues found that people who
learned a particular task did not improve their performance when
tested later the same day but did improve after a night of sleep.

To see whether the night of sleep actually caused the improvement,
Stickgold trained 24 subjects in the same visual discrimination
task, which consisted of identifying the orientation of three
diagonal bars flashed for a sixtieth of a second on the lower left
quadrant of a computer screen full of horizontal stripes. Half of
the subjects went to sleep that night while the other half were kept
awake until the second night of the study. Both groups were allowed
to sleep on the second and third nights. On the fourth day, both
groups were tested on the visual discrimination task. Those who
slept the first night identified the correct orientation of the
diagonal bars much more rapidly than they had the first day. The
other group showed no improvement, despite the two nights of
catch-up sleep.

"We think that getting that first night's sleep starts the process
of memory consolidation," says Stickgold. "It seems that memories
normally wash out of the brain unless some process nails them down.
My suspicion is that sleep is one of those things that does the
nailing down."

Support for this research was provided by the National Institutes 
of Health and The Network on Mind-Body Interactions, a
multidisciplinary research network sponsored by the John D. and
Catherine T. MacArthur Foundation. Begun a decade ago, the Mind-Body
Network ( has been committed to discovering
the biological mechanisms by which the social world and mental
processes affect physical health.




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