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Ability to Learn Is Affected by the Timing of Sleep

Researchers find that how soon we sleep after learning new information impacts how well we retain it. Christie Nicholson reports














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Sleep has many functions—including facilitating learning.

Now a study finds that when we acquire new information, and how soon we sleep after that may affect our retention of the info. That’s according to research in the journal Public Library of Science One.

Scientists had more than 200 subjects memorize related words like “fire and smoke,” or unrelated word pairs like “insect and truth." Some studied the words at 9 A.M., others at 9 P.M.

The researchers tested the subjects’ ability to remember the pairs after 30 minutes, 12 hours or 24 hours.

Sleep had little effect on the ability to recall related words. But subjects who slept between tests were significantly better at remembering the unrelated words than those who got no shuteye.

Here is the most interesting finding: In the 24-hour retest—where all subjects had a full night of sleep—those participants who went to bed shortly after learning the words did much better than those who went through an entire day before sleeping.

And this leg up in memory was maintained on subsequent days. So if you need to remember something, try reviewing those notes just before bedtime. Instead of watching that rerun of Seinfeld you already have memorized.

—Christie Nicholson

[The above text is a transcript of this podcast.]


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  1. 1. em_allways_right 01:04 PM 3/25/12

    I like that finding as my text books put me to sleep anyway.

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  2. 2. jtdwyer 03:22 PM 3/25/12

    This finding is consistent with a general conception of human memory modeled after Data Base Management System software (which, after all, may have been based on a conception of human memory and efficient physical resource management methods).

    In this scenario, short term memory is used to store new information as quickly as possible, without regard to its most effective storage utilization or the performance of its later, most frequent method of access. This short term memory is of limited capacity: once it fills up further storage of new information must in some way be inhibited. One method might be to wrap over exiting short term memory storage, replacing previously stored memories.

    To free up short term memory for subsequent use and most efficient storage of its retained information, the system must be inactivated (go to sleep), preventing the acquisition of new information. During this inactive period, the new information contained in short term memory can be migrated and associated with existing information stored in long term memory. Redundant components may be may be reduced to a link to an existing memory. Related indices may be updated to point to the newly stored information for optimal retrieval so that, for example, all grocery store locations can be quickly recalled.

    In this way, prior memories may be slightly altered to accommodate associated information from newly acquired separate memories. This could be a primary reason why memories change over time.

    In this scenario, memories are stored in short term memory as quickly as possible, to maximize information acquisition while minimizing operational interference. Long term memory is organized and managed during operational down time to optimize space usage and retrieval performance and flexibility at the cost of additional information storage processing time. It can explain why sleep is so crucial to the effective storage of information and how existing long term memories can be modified or degraded over time.

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  3. 3. abrasileirosilva 08:20 PM 3/25/12

    The site below has encompassing and interesting text about the theme treated by this podcast, especially in the items *Declarative memory* and * Declarative memory consolidation during sleep* (the last paragraph of this latter item deserves special attention).

    http://encyclopedia.thefreedictionary.com/declarative+memory

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  4. 4. ThinkSDG 11:57 AM 3/27/12

    This is intriguing. Cramming at the last minute the night before... but getting sleep afterward... is supported by this. This also speaks to why adult learners, who often can only study at night after work, seem to do better "at school" when they are older than what they did when they were younger.

    It makes you wonder about school schedules and parents' requirement to finish school work as soon as the kids get home rather than waiting until they are about to go to sleep.

    I look at the path of all learning on my blog at http://www.thesdggroup.com/blog.aspx. I am going to give some serious consideration to how sleep contributes to this.

    SDG

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  5. 5. irenealhanati 04:34 PM 3/29/12

    It is a very interesting find.It is also interesting to realize that after we sleep we may find an answer to a problem we were worried about before going to bed. This happened to me many times.

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  6. 6. irenealhanati in reply to abrasileirosilva 04:37 PM 3/29/12

    Thank you, dear abrasileirosilva. Um abraço.

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  7. 7. Robotics101 11:45 PM 4/6/12

    This research did not do what everyone thinks it did. First of all, this was not about learning or learning vocabulary. Let's make that clear. The participants already knew the vocabulary. If you think this research was about learning and learning vocabulary then you're sorely mistaken. Then what was this research really about? If the participants already knew the vocabulary, what was it they really did? What they really did was remember the sequence in which the paired words appeared. That is, they remembered the order of the words, not the words themselves. So what is the link to learning? It is merely the ability to remember the sequence. The participants demonstrated they could make use of an already existing ability. If you had to learn the words from scratch, I guarantee you'd get a vastly different result. All the research highlighted was the ability perform a simple pattern recognition task. Not knowing the full study methodology though, it's hard to draw other conlusions. For instance, in the first paired words group, there are two concrete content words connected by and; in the second pair, one concrete content and one abstract content word connected by and. Being able to remember these words so easily was due to the fact that they were already known. That reduces the cognitive load to learn considerably, because really, there was nothing to learn. And if the paired words were presented in the post-task test, I'd be very surprised if anyone actually failed it.

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  8. 8. m.abbasi 03:27 PM 7/2/12

    I believe this kind of memorizing and i have tested it before.the reason why sleep can affect memorizing in a good way is that before sleeping your mind is calmer than the other times and u try to push all of the problems and stresses out of your mind.also the brain has the best time to organize the information that u have gained when u are sleeping and it doesnt have a lot of works to do.

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