单选题
Before a big exam, a sound night's sleep will do you
more good than poring over textbooks. That, at least, is the folk wisdom. And
science, in the form of behavioral psychology, supports that wisdom. But such
behavioral studies cannot distinguish between two competing theories of why
sleep is good for the memory. One says that sleep is when permanent memories
form. The other says that they are actually formed during the day, but then
"edited'' at night, to flush away what is superfluous. To tell
the difference, it is necessary to look into the brain of a sleeping person, and
that is hard. But after a decade of painstaking work, a team led by Pierre
Maquet at Liege University in Belgium has managed to do it. The particular stage
of sleep in which the Belgian group is interested in is rapid eye movement (REM)
sleep, when brain and body are active, heart rate and blood pressure increase,
the eyes move back and forth behind the eyelids as ff watching a movie, and
brainwave traces resemble those of wakefulness. It is during this period of
sleep that people are most likely to relive events of the previous day in
dreams. Dr. Maquet used an electronic device called PET to
study the brains of people as they practiced a task during the day, and as they
slept during the following night. The task required them to press a button as
fast as possible, in response to a light coming on in one of six positions. As
they learnt how to do this, their response times got faster. What they did not
know was that the appearance of the lights sometimes followed a pattern--what is
referred to as "artificial grammar". Yet the reductions in response time showed
that they learnt faster when the pattern was present than when there was
not. What is more, those with more to learn (i. e., the
"grammar", as well as the mechanical task of pushing the button) have more
active brains. The "editing" theory would not predict that, since the number of
irrelevant stimuli would be the same in each case. And to eliminate any doubts
that the experimental subjects were learning as opposed to unlearning, their
response times when they woke up were even quicker than when they went to
sleep. The team, therefore, concluded that the nerve
connections involved in memory are reinforced through reactivation during REM
sleep, particularly if the brain detects an inherent structure in the material
being learnt. So now, on the eve of that crucial test, maths students can sleep
soundly in the knowledge that what they will remember the next day are the basic
rules of algebra and not the incoherent talk from the radio next door.
单选题
Researchers in behavioral psychology are divided with regard to ______
.