It has been common scientific knowledge for some time that when we sleep, our brains consolidate the information we subconsciously absorb during the day, and process it into explicit, conscious knowledge.
Both children and adults do this, but a new study out of Germany shows that during sleep, children’s brains convert subconsciously absorbed information — known as implicit learning — into active, useful knowledge even more effectively than adult brains do.
The study was conducted by Dr. Ines Wilhelm of the University of Tübingen's Institute for Medical Psychology and Behavioral Neurobiology in Germany, and colleagues.
Implicit vs. explicit learning
Implicit learning is typically defined as subconscious learning; the acquisition of knowledge that is independent of conscious attempts to learn. It is absorption of information without conscious intent or awareness.
Explicit learning, on the other hand, is conscious learning; the active and aware acquisition of skills and/or knowledge. Typically, explicit learning is accompanied by “meta-awareness,” a person can explain how they acquired the skill and/or knowledge.
During sleep, implicit knowledge becomes explicit memory, making future learning easier, and therefore becomes more easily transferred to other areas.
Previous study: sleep helps implicit learning in adults
Previous studies of adults have shown that sleeping after learning supports the long-term storage of the material learned. In a 2007 study published in the Journal of Cognitive Neuroscience, adult subjects took part in a training session in which they implicitly learned the rules of a task performed on the computer.
The researchers knew the subjects were learning implicitly because they could complete the task faster, even though they couldn’t say why or how. But following a night of sleep, the subjects were tested again, and shaved nearly 10 more seconds off their reaction time. The researchers concluded that, “the off-line learning process that continues after practice has ended was crucially enhanced by sleep.”
Results of the study
In the current study, entitled, “The sleeping child outplays the adult’s capacity to convert implicit into explicit knowledge,” the researchers followed a similar research model to the 2007 study, but included child subjects, in addition to adults.
The researchers studied 35 children between the ages of 8 and 11 years old, as well as 37 adults between 18 and 35. For the test, the subjects were asked to press a sequence of buttons after they lit up. Half of the subjects did the test before sleep, the other half after sleep. They were then asked to recall the sequence of buttons/lights 10 to 12 hours later. Following a night of sleep or a day awake, the subjects’ memories were tested.
The results of the study, which are published in the February 24, 2013 online edition of Nature Neuroscience, showed that after a night’s sleep, both age groups remembered a larger sequence of buttons/lights than those who did not sleep. It also showed the children were better at it than the adults — almost all of the children could remember the sequence they had pressed perfectly, while adults experienced smaller gains.
Children absorb massive amounts of information every day. They also generally sleep longer and deeper, and experience three times more slow-wave sleep and higher electrical activity in the brain during sleep than adults. This may help them “convert” the information they take in every day into knowledge they can recall and use.
Lead author Dr. Ines Wilhelm wrote, “In children, much more efficient explicit knowledge is generated during sleep from a previously learned implicit task. And the children’s extraordinary ability is linked with the large amount of deep sleep they get at night. The formation of explicit knowledge appears to be a very specific ability of childhood sleep, since children typically benefit as much or less than adults from sleep when it comes to other types of memory tasks.”