Sleep Disorders

Sleep and Learning

Common sense holds a well-rested person can learn more easily and more thoroughly than a sleepy person. Let’s look at the science.

Rested brains learn more readily. Well-rested (not sleep- deprived) brains do a bunch of tasks better than sleepy brains. In tests of response time to stimuli, agility, ability to remember new material and to perform things like mental arithmetic this has been shown again and again. It’s so cliché that these types of tests are performed by psychology students early in their training in order to get their feet wet with research.

A more interesting finding is how sleep after learning something helps cement the learning. During sleep the brain turns recently acquired memories into long term memories. Sleep helps lock in the learning. This appears to be one of the main biological functions of sleep.

EEG readings of stage 2 sleep show short bursts that sleep scientists have named Spindles (because of how they look on the EEG record.) Each Spindle lasts about a second, and there may be as many as a thousand in each person’s brain every night. Spindle events are not understood by neuroscientists. It is suspected they have something to do with the transfer of memory from the hippocampus to the frontal cortex and the formation of long-term memories. Sleep spindle activity is associated with the integration of new memories with existing knowledge. The number of spindle events, and deep sleep, declines in old age, which is thought to correspond to overall decline in mental acuity in older people.

The light sleep of stages 1 and 2 have been shown to be important in helping the brain being plastic to learning new material. This also points to an explanation for why a 90-minute nap in the day can help people remember material they just learned. And why "sleeping on it" often helps people mentally digest their situation.

Memory formation and abstract concepts

Sleep is particularly important in learning higher-order abstract concepts. Research has found a significant correlation between the level of improvement in tests of learning and the amount of slow-wave sleep obtained. People consolidate the new learning much better after a period of sleep than during a waking day. Even an afternoon nap helps. Sleep-dependent consolidation of statistical learning.

Slow wave (deep) sleep promotes episodic declarative memory consolidation. This is the more important type of memory for schoolwork, in contrast with procedural memory which is important for physical actions. Daytime naps are paticularly useful for consolidating new procedural memories.

The decline in the amount of time spent in slow wave sleep among old people may explain why older people have a harder time learning new things that younger people. It is indeed hard to teach an old dog new tricks, partly because the dog’s sleep patterns have changed.