Introduction

Scientists have been studying the relationship between sleep and memory for some time. We would like to study one aspect of this massive topic. We believe a person’s ability to retain information is affected by his amount of sleep. The problem we face is that many people get fewer hours of sleep, and we would like to test if these people would have worse memory retention skills that are necessary in school life. Our hypothesis is that if a person gets less sleep, he will have more trouble remembering things in the morning than if he gets more sleep. Our independent variable is the length of time our subjects sleep, and our dependant variable the memory quality. We will test this hypothesis by giving each subject a list to be read and remembered just before going to sleep. They will also record when they read the note, and when they wake up in the morning. Immediately after waking up, we will quiz them on what they remember of the list. This will test memory retention. We will compare each test subject’s score against a second test in which they sleep longer, and we will see if this allowed them to remember more. From this, we will deduce our results.

Studying is an important part of school life. What is the best way to maximize the effect of studying? Studying is the ability to retain information, to make connections between new material and old. Many people have different ideas as to how to increase the efficiency of studying. Most say that memory is key, that it is the most important step in studying. From there, their views begin to differ. Some believe that innate intelligence is the root of a good memory, that memory is not learned; that people are born with a certain ability to retain information. Some educators believe there is a magical formula; that doing certain exercises or using different acronyms is the way to improve memory capacity. Janet Nielsen, a dietitian, thinks that the diet is more important. In the Gazette, on November 3rd 2004, she stated that eating eggs and strawberries and drinking milk would contribute to higher alertness and better performance on tests or exams. Finally, another group points to the role of sleep in developing memories. Human beings sleep, on average, a third of their day. So, naturally, there have been a lot of experiments as to why this function is necessary.

We have reviewed how sleep is an important part of our lives, and how our sleep patterns changed remarkably over the years. In the time of early man, our ancestors slept long hours each night. They didn’t stay up late as we do now because they couldn’t. They had no source of light other than their flickering fires. Humans adapted to ten hours of sleep every night. They were well rested in the morning and ready for another long hike and a full day of hunting. When they were disturbed in the night, they were too tired in the morning to focus properly. When they slept well, they protected themselves and survived. In present times, however, he who does more work and gets less sleep is considered to be superior. Our biological clocks didn’t change, so what did?

As gas lights became common in use, a huge blow was dealt to sleep cycles. Now meetings could be held after dark. Not only were people staying up later, they were waking up earlier then ever before. Most servants’ tasks could be completed in half-light, so they could wake up earlier to start their chores. Most people began to stay up later too. They roamed the streets at night under gas lamps, and late nights became common.

In our Internet society, business deals across the oceans are being contracted at every minute of every day. Due to the time difference between places, one of the two has to reach into their sleep bank for a few hours to make the meeting. Some people even go without sleep for the night; the night shift has to snooze in the afternoon. These activities seriously affect the biological clock of the human body, messing up people’s brains so it is harder to produce clear thought or retain information. In North America, working long hours – or pulling an “all nighter” is seen as a good thing. Those who sleep less are congratulated, as if they care more about their work than others. In his book Sleep Thieves, Dr. Stanley Coren discusses the changing public view on sleep.

As early as 170 AD, scientists came out with new theories on how the brain worked. Roman physician Galen, in began to wonder where thought came from. His theory was that emotion, learning, and memory were all functions of the brain, an organ previously considered useless. Jumping forward many centuries, scientists began to make the connection between sleep and information retention. The book Sleep and Brain Plasticity, tells that in 1885, researcher Ebbingham gave people a list of nonsense words. They were able to recite from memory more of the words after a night’s sleep than when they were quizzed shortly after receiving the words. In 1914, a researcher named Heine taught people random syllables before sending them to sleep. When they woke up, the people who had learned the sounds just before going to bed recalled more than those who had been taught earlier in the day. Both researchers concluded that sleep was a major influence on the development of memory.

In the 1920s, Dr. Nathanial Kleitman and his team pioneered sleep research. They observed different types of sleep including the REM phase (rapid eye movement) during which people dream. Professor Baddeley’s book of 1982, Your Memory- A User’s Guide states that there is a chemical process in the brain that may operate more effectively at night. There are body temperature and hormonal changes, which may be important to the connections made when memory links are formed. Their studies provide important insight to the processing aspects of sleep.

The World Federation of Sleep Research Society was founded in 1987. Scientists from all over the world began following sleep patterns and discovering new information related to sleep. Sleep research results were made more public, and many internet sites were devoted to the spreading of new knowledge.

Our project focuses on the relationship between insufficient sleep, and short term memory retention. Stanley Coren’s book, Sleep Thieves documents the role sleep debt plays in our ability to remember things, and how our lives are affected by it. He give the example of a military school, where, when students in a class were given 1.5 hours more than their peers’ regular 7.5 hours of sleep, the class average was almost ten per cent better then the other classes’ average.

Since our experiment focuses on teenagers (ages 12-14), we looked for information about teenagers’ sleep patterns. Researchers for PBS in the program Frontline: Inside the teenager’s brain took a close look at a teenager’s life-cycle, and how sleep (or lack of it) affects them. They found that as the teenagers went through puberty, their brain undergoes large changes. Changes in the brain cause massive disturbances in the teenager’s lifestyle, and, more importantly, in their sleeping habits. The teen begins to stay up later; one who once slept nine hours a night now rests for seven or eight. Late nights are common, but early mornings are still required. PBS’ studies found that these odd hours were not due merely to choice; teenagers’ brains kept them alert at 10:00, when they would normally go to sleep. The students had to wake at an early hour, but would still be unable to sleep at a reasonable time because their brains were against them. We theorize that their lack of sleep affects their memory retention, and so, their school work.

Several terms have been identified in this review that are key to understanding our project.

The circadian rhythm is the cycle of awake/sleep time; also known as the biological clock. It runs over a period of 25 hours, which may seem strange compared to a 24 hour day, and it is, but since the biological clock resets every morning upon contact with the sun, it all works out and is not noticeable at the end of the day. It was found out that humans operate on a 25 hour cycle when two scientists, Nathaniel Kleitman and a colleague, locked themselves away from the cues of the 24 hour day in an underground chamber in Mammoth Cave, in Kentucky. Without their biological clock resetting every morning, the men fell asleep one hour later each night. The blind find they have the same problem. They have no response to the sun, so on some nights, they have trouble falling asleep and some days they cannot stay awake because they live in a 25 hour state of mind in a 24 hour world.

Also, the circadian rhythm has high and low points. People are more tired at some points in their daily cycle than others. These time zones are 1-4 am and pm. More accidents on the road happen at these low points than at any other time. People sometimes attribute their sudden sleepiness in the afternoon to their midday meal, but it is not the case. Those countries that enjoy the custom of siestas typically do so at the low point of the circadian rhythm.

Sleep debt is when a person gets less sleep than is normal for any reason. He is missing out on hours of sleep that are necessary to feel well and rested – or retain information better.

There are many types of memory. The form of memory in our project is short term, or declarative, memory. These are the facts and memories that have to be consciously memorized or called to attention.

There are many things scientists still don’t know about sleep and how it affects memory even though much research has been conducted on each of these elements. Theories have been tested under certain circumstances, but have not been properly proved. Since most sleep experiments have been conducted at night, complying to circadian rhythms, it isn’t really certain what effect the cycle has on the outcomes. Scientists still don’t know exactly how memories are formed. They know that links have to be formed between cells in the brain, and that the links are solidified during sleep, but they aren’t sure what does exactly what. For example, Dr. Baddeley only stated that the chemical changes might affect the memory trace and that other factors might have an influence. There are many uncertainties in the field of sleep and memory research, and the results of research can affect many areas of life.

The risks associated with lack of sleep are well known. Experiments and real-life situations demonstrate the dangers we expose ourselves to when sleep deprived. In the nuclear power plant at Chernobyl in Ukraine, sleep deprived workers pressed the wrong keys and made a correctable situation much, much worse. Radioactive materials worked their way into the soil causing long term damage. The workers had been too long on the shift, and they were too tired to make the right choices. Perhaps they had even forgotten what they were supposed to do in that particular emergency. Even against this tragedy, society continues to praise the sleepless long-shift workers. Science tells us that we need a certain amount of sleep, but we continue to disregard the evidence.

One group that is definitely not benefiting from the research is the teenagers. They are still forced to comply with the workday schedule, even though it has been proven without a doubt that their sleep cycles make that difficult.

All we can hope for in the future is a life without sleep debt. There would be no sleep related accidents or deaths. People would be in good humour and in their right mind. They would all be well rested, and their memories would have enough time to solidify in their minds overnight. Sleep debt can only be paid off with sleep, but where will the North Americans of tomorrow take this sleep time from?

Teenagers always seem to be tired, taking hours to get out of bed and falling asleep wherever they can. Every day they have to get up early for school but go to sleep late because of their sleep cycles. Obviously, the simple solution is to push back the starting time of school. In the future, scientists will hopefully be able to answer more than whether or not sleep deprivation has anything to do with overall performance and will be able to pinpoint the ideal time for adolescents to get to school late enough that they aren’t tired and early enough that they can get home before dusk. Future sleep research will find a way to accommodate the strange sleep cycles of teenagers of tomorrow.

In the future, scientists will be able to show exactly what part of sleep helps retain memories, even though now all they know is that it does. Using new technology like brain scans, future research may be able to uncover some ideas about how exactly we create our memories in the brain and what role sleep plays in that creation.

Will it be possible for scientists in the future to create an ingestible pill with all the needs of sleep rolled into one? Could a pill rest for us and process our memories even as we live our day, without having us suffer the loss of one third of our precious lives? Or will future research in this area conclude that sleep is essential to humans, and set up a bedtime at nine? Will we have to change our outlook on life that says that the student or colleague who can function on less sleep is to be honoured? Many believe that sleep is valuable to retaining information. When scientists find exactly how much sleep is necessary, perhaps sleep will then become another chore, a task that that has to be completed every day to assure memory retention.