Introduction

    Memory consolidation suggests that during sleep memories are not just moved to long term storage but also reinforced and improved. Almost all experiments done on memory consolidation have been in a controlled lab, where the participants had their sleep regulated and monitored. This includes having them not sleep at all, having them get the exact amount of sleep, or only getting certain stages of sleep. All of these are simply not possible at Wakefield School. Instead of recreating a lab done study on sleep and memory I decided to do a simple experiment to see if just one night of sleep can actually help memory. 

 

 

Literature Review

    The relationship between sleep and memory is not a new discovery, but it is still not a concrete science. Although they are not fully known, memory and learning can be broken down into three parts: acquisition, consolidation, and recall. Acquisition is new information being introduced into the brain, consolidation is the process of memories being stored in the brain, and recall being the ability to access the information after storage (“Sleep, Learning, and Memory”).   

    When something is learned the new memory that is created is not immediately stored in the neocortex for long term storage, but instead in the hippocampus. These new memories that are stored in the hippocampus are vulnerable to being forgotten unless they are consolidated. During consolidation the memories that are temporarily stored in the hippocampus are reorganized and moved to the neocortex for later retrieval (Squire, Larry R, et al). The process of consolidation takes time and is mostly done during sleep, which is one of the reasons why sleep is essential with learning and memory. 

Sleep is also a key process for acquisition. Besides sleep’s necessity to help people focus on and study new information it also helps the hippocampus. As the hippocampus stores new information it begins to fill up and, “if the hippocampus is full, and we try to learn more information, we won’t be able to” (Cappello). Without sleep, people will reach a limit on how much information can be gained.

    Recall appears to be affected by sleep the same as the other two parts of memory. During sleep, the brain filters out what information to keep and what to discard. The discarded information can obviously not be recalled. The memories that can be recalled are the ones that were consolidated and moved into long term storage. Aside from just discarding and storing memories, sleep also improves the memory of them, “[scientist found] that sleep improves memory retention and recall by between 20 and 40 percent” (Cappello). Without sleep, the total number of memories retained will drop, and what memories stick drop in quality.

    Besides sleep’s general benefit to memory, the different stages of sleep help different kinds of memories. Sleep can be broken down into two main stages: non rapid eye movement, NREM, and rapid eye movement, REM. These two phases handle different types of memory. NREM focuses on declarative memory which is fact based information. During this stage of sleep, memories are moved from the hippocampus to permanent storage. The other main stage of sleep, REM, handles more procedural memory, “the remembering ‘how’ to do something (for example, riding a bicycle or playing the piano).” Consolidation takes place during this stage of sleep as well (“Sleep, Learning, and Memory”). 

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Hypothesis

    The idea for this experiment is to test whether a night of sleep has a substantial effect on memory that could outweigh staying up to study more. After consulting Mr. Zontine I realized that in this experiment I had to be sure to only test memory. My first sketch of the experiment had the participants memorizing vocabulary, but this could add error to the data if some of the participants are gifted in vocabulary. To avoid this I decided to have the participants memorize an image then test them to see how well they memorized it. Since the experiment is to see if sleep will improve memory, a control is needed where the participants take the test without sleeping. Another test will be administered where the participants take the test the day after studying the image so they can sleep. The way people study the image and the time they spend studying can impact the results so both the time and resources to study are limited. The premise is that everyone should score better on the test after sleeping compared to the first test, since during sleep the brain will consolidate the memories.    

 

Study 1

    In the first part of study 1, the participants were given the following images and instructions of what to do. The participants were given ten minutes to study, once that time elapsed the image was taken from them. Forty five minutes later a short quiz was given to the participants to test their memory.

 

   

 

 

 

 

 

 

 

 

 

    The Instructions 

You have ten minutes to memorize this image to the best of your ability.

    The Quiz

Write down as many of the symbols that appeared on the image as you can.

    The following graph is the score that the participants got without sleep.

 

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For the second part of study 1, the same participants were given the following image and instructions. The next day they were given the quiz.

   

 

 

 

 

 

 

 

 

 

 

    The Instructions

Please study this image to the best of your ability anytime before sleeping. Study this for no more than ten minutes. 

    The Quiz

Write down as many of the symbols that appeared on the image as you can.

    The graph below shows the scores that the participants got after sleeping.

 

 

 

 

 

 

 

 

 

 

 

 

 

Study 2

    In the first part of study 2, a different group of participants were given the following image and instructions of what to do. After the time to study the image passed the image was taken from them. Forty five minutes after that a short quiz was given to the participants to test their memory.

 

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    The Instructions 

You have five minutes to study this image to the best of your ability. 

    The Quiz

Write down as many of the symbols that appeared on the image as you can. 

    The following graph is the result of first part of study 2.

 

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For the second part of study 2 the same participants were given the following image and instructions. The next day they were given the quiz.

 

 

 

 

 

 

 

 

 

  

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    The Instructions 

You have five minutes to study this image to the best of your ability. 

    The Quiz

Write down as many of the symbols that appeared on the image as you can. 

The following graph is the result of second part of study 2

 

 

 

 

 

 

 

 

 

 

 

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Methods

Wakefield School Sample 

  

    Participants:  I tested eleven students from Wakefield School.

 

    Materials:    For the part of study I gave each participant a copy of the first picture, and gave one group ten minutes and another group five to study it to the best of their abilities. After the study time elapsed I took back the images and after forty five more minutes gave the participants the test. The test asks the participants to write down as many of the symbols that were on the image as possible. For the second study I followed the same study procedure except instead of the first picture I gave the participants the second. As for the testing, instead of waiting forty five minutes I gave them the test the following day. 

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Results 

    In study 1, the first graph shows the results of students without sleep. The mean score is 13.8 with a high of 20 and a low of 8.

    The second graph shows the same students’ results with sleep. The mean score is 12.6 with a high of 18 and a low of 8.

    In study 2, the first graph shows the results of students without sleep. The mean score is 18 with a high of 20 and a low of 16.

The second graph shows the same students’ results with sleep. The mean score is 18.1 with a high of 20 and a low of 15.

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Discussion

    The results of this experiment are not what I was expecting and are different from what the research shows. Although the ten-minute group had twice the amount of time to study the words, they scored worse than the five-minute group in both with and without sleep. The reason for this is simply that the students in study 2 were more academic than the students in study 1. Another part of this experiment that needs to be addressed is the two study times. Originally I planned to do just one time of ten minutes, but after giving the first group of students ten minutes, I realized that they were given too much time.

    Surprisingly the data reject my hypothesis and shows that sleep does not have an effect on memory, yet lab studies show that the opposite is true. This may have happened because the experiment was not important to the participants. Not every memory gets consolidated, and to a student, the memories made in the classroom outweigh the ones from an experiment by one of their peers. Another reason why the data rejected the hypothesis is because of the sample size. This experiment had a very small sample size and just a single outlier greatly affects the data. But it is not that the experiment failed completely. Five of the participants’ scores increased after sleeping, three stayed the same, and three scored worse. The five that did increase increased by an average of 2.2 points or 11%. The three who scored worse dropped by an average of 5.3 points due to an outlier. Removing the outlier changes the average to 2 points, dropped or 10%. Although the data does not definitively prove that a single night of sleep will help with memory, it does not show that a night of sleep is harmful. Seventy-three percent of participants had the same score or improved after a night of sleep. Even if a student’s memory does not improve if they get a night of sleep, the benefit they will get from being well-rested may give them extra help on a test. Besides the results, there are some other issues with the experiment, mainly with the participants.

    I learned from this experiment that I needed a random sample of participants. I chose the participants out of convenience, which led to one group being more committed and having a significantly higher score. When conducting this experiment, I should have gathered random students to participate instead of the students in my classes. I also should have given them the ability to pick which day they participate so they could have avoided participating during a day when they had more important things cluttering up their brain. Adding those two things into this experiment would have leveled out the disparity between the two groups and stopped participants from having a large drop in scores after sleeping.

    Although the experiment did not turn out how I expected, it still showed a small increase in memory upon sleeping. But the experiment did show that there is not a meaningful decrease in memory which means that people who get a full night of sleep will get the same scores on a test as someone who stayed up without any sleep deprivation.