Chapter 3. How Would You Know If Sleep Deprivation Affects Academic Performance?

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C. Nathan DeWall, University of Kentucky

David G. Myers, Hope College

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Note: You will be guided through the Intro, Design, Measure, Interpret, Conclusion, and Quiz sections of this activity. You can see your progress highlighted in the non-clickable, navigational list at the right.

Watch this video from your author, David Myers, for a helpful, very brief overview of the activity.

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So, how would you know if sleep deprivation affects academic performance? To study this question effectively in your role as researcher, you need to DESIGN an appropriate study that will lead to meaningful results, MEASURE your participants’ academic performance, and INTERPRET the larger meaning of your results, considering how your findings would apply to the population as a whole.

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Correlational Studies:

Experiments:

Case Studies:

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You have chosen to use a Correlational design, which means you want to examine the association between two or more variables. For example, when testing whether number of hours spent studying relates to average scores or grades in a course, researchers would recruit a large group of students and measure how much time they study and their average grades. This allows researchers to determine whether the amount that students study relates to having higher average grades. (It does. Keep studying!)

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With a Correlational design, we might examine the association between the number of hours students sleep and their academic performance. As a result, we would learn something about the relationship between sleep duration and how well students learn and remember information. But we would not know whether sleep deprivation causes changes in academic performance. Other factors may also explain the relationship between sleep duration and academic performance, such as how quickly students learn information. If certain students learn quickly, perhaps they simply have more time to sleep as a result? To know whether sleep deprivation affects academic performance, we need to systematically change how much students sleep and then measure their mental abilities.

So, CORRELATIONAL IS NOT THE BEST RESEARCH DESIGN for this study. We’d get more helpful results by using a different design.

Click “Next” to go back and try again to select the most effective research design.

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You have chosen Case Study as your design. With a Case Study design, you will choose one student or a small group of students, such as a specific group of students who have sleep disorders—perhaps those with insomnia or narcolepsy—and then study them in depth.

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What could we learn from these participant choices?

a. One student or a small group of students who have insomnia Studying students with insomnia could tell you something about the effects of disrupted sleep, but with this design, you would not be able to determine if sleep deprivation causes a change in academic performance. You need to recruit a large number of students who have healthy sleep patterns, and then systematically change their sleep duration to determine how that influences academic performance.

b. One student or a small group of students who have narcolepsy Studying students with narcolepsy could tell you something about the effects of disordered sleep patterns, but with this design, you would not be able to determine if sleep deprivation causes a change in academic performance. You need to recruit a large number of students who have healthy sleep patterns, and then systematically change their sleep duration to determine how that influences academic performance.

c. One student or a small group of students who have healthy sleep patterns You were right to select participants who have healthy sleep patterns. However, studying only one student or a small group of students would not help you learn about whether sleep deprivation affects academic performance in the broader population.

d. One student or a small group of students who have insomnia and another student or small group of students who have narcolepsy Studying students with sleep disorders could tell you something about the effects of disordered sleep patterns, but with this design, you would not be able to determine if sleep deprivation causes a change in academic performance. You need to recruit a large number of students who have healthy sleep patterns, and then systematically change their sleep duration to determine how that influences academic performance.

Trying to choose a sample of participants helps us realize that CASE STUDY IS NOT THE BEST RESEARCH DESIGN to test this question. We’d get more helpful results by studying large groups of students who have healthy sleep patterns, which would allow us to apply our results to a broad population. We would also want to measure academic performance in a controlled setting. This would help us determine whether sleep deprivation can affect academic performance.

Click “Next” to go back and try again to select the most effective research design.

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Nice work! You have correctly chosen to use an Experimental design for your study.

Next, you need to choose the most appropriate study participants. (Note that those with insomnia have recurring problems in falling or staying asleep. Narcolepsy is characterized by uncontrollable sleep attacks, such as lapsing directly into REM sleep, often at inopportune times.)

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You chose A group of students who have insomnia, but that is NOT CORRECT. Studying students with insomnia could tell you something about the effects of disrupted sleep, but you would not be able to determine if sleep deprivation causes a change in academic performance. You need to recruit students with healthy sleep patterns, and then systematically change their sleep duration to determine how that influences academic performance.

Click “Next” to try again to choose the most appropriate study participants.

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You chose A group of students who have narcolepsy, but that is NOT CORRECT. Studying students with narcolepsy could tell you something about the effects of disordered sleep patterns, but you would not be able to determine if sleep deprivation causes a change in academic performance. You need to recruit students with healthy sleep patterns, and then systematically change their sleep duration to determine how that influences academic performance.

Click “Next” to try again to choose the most appropriate study participants.

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You chose A group of students who have insomnia and another group of students who have narcolepsy, but that is NOT CORRECT. Studying students with sleep disorders could tell you something about the effects of disordered sleep patterns, but you would not be able to determine if sleep deprivation causes a change in academic performance. You need to recruit students with healthy sleep patterns, and then systematically change their sleep duration to determine how that influences academic performance.

Click “Next” to try again to choose the most appropriate study participants.

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Good job! You have correctly chosen to use an Experimental design, with participants who have healthy sleep patterns, in which you will systematically change how much participants sleep over the course of one night before completing your measure of academic performance. Using random assignment, such as by flipping a coin, to minimize any preexisting differences between the two groups, you will assign half of your participants (the well-rested group) to sleep eight hours. The other half of the participants (the sleep-deprived group) will sleep only one hour.

Now you need to determine how best to MEASURE the relevant behavior or mental process, which in this case is academic performance. Let’s say we will measure academic performance with a test of learning and remembering.

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You chose Have participants report their level of mental energy, but that is NOT CORRECT.

This option would tell you whether well-rested participants felt they had more mental energy than sleep-deprived participants did, but it would not give you the information you need about whether the sleep differences influenced academic performance. To know whether sleep deprivation affects academic performance, you need to measure students’ ability to learn and remember.

Click “Next” to try again to select the best way to measure whether sleep deprivation affects academic performance.

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You chose Have participants answer the following question, “How well can you learn and memorize academic information RIGHT NOW, that is, at the present moment?” (1=not well at all to 7=extremely well), but that is NOT CORRECT.

This option would give you information about whether your participants feel confident in their ability to learn and memorize information, but it would not tell you anything about their actual academic performance. If you want to know whether sleep deprivation affects academic performance, you need to measure actual academic performance behavior.

Click “Next” to try again to select the best way to measure whether sleep deprivation affects academic performance.

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You chose Have participants report their average scores or grades from all of their courses, but that is NOT CORRECT.

Average grades would be measured before you could implement a systematic change in sleep duration. Knowing participants’ average grades will not tell you if systematic changes in their sleep duration affect their current ability to learn and memorize information. To know whether sleep deprivation affects academic performance, you need to alter sleep duration in two groups of students (sleep-deprived versus well-rested), measure their ability to learn and memorize information, and then compare the results from each group.

Click “Next” to try again to select the best way to measure whether sleep deprivation affects academic performance.

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Good job! You have correctly chosen to use an Experimental design, in which you will systematically change how much participants sleep before they complete a measure of academic performance. Using random assignment, half of your participants (the well-rested group) will sleep eight hours. The other half of the participants (the sleep-deprived group) will sleep only one hour.

You also chose an appropriate sample of participants—a group of students who have healthy sleep patterns. And you chose an effective way to MEASURE academic performance. You chose to Have participants learn nonsense syllables and then try to recall them.

In similar studies, researchers have in fact found that getting a full night of sleep does help the brain reorganize and consolidate information (Squire & Zola-Morgan, 1991). When sleep-deprived people try to learn and remember information, their groggy brains limit their ability to perform well. In one study, people deprived of sleep for 25 hours, compared with those who got a full night of sleep, suffered large memory impairments, which would hurt academic performance (Grundgeiger et al., 2014). Just think of this result the next time you’re tempted to pull an all-nighter!

Knowing all this, you now need to consider how you can apply what you’ve learned to the larger population—beyond the people you’ve studied. Consider where you might encounter roadblocks to confidence in your results. What factors might keep you from being able to apply what you’ve learned in a broader context?

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You tested whether sleep deprivation affects academic performance. There are many factors that could affect how well students learn and remember information. Some of these factors may have nothing to do with how much students sleep! Factors that could interfere with our INTERPRETATION of results are called confounding variables.

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Confounding Variables:

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Credit: Tara Moore/Stone/Getty Images

The confounding variables for your study would include those highlighted below:

The highlighted confounding variables relate to your confidence in your study design and measurement approach. You need to keep track of participants’ natural ability to learn and remember information. Imagine if students who are naturally gifted memorizers end up in the well-rested group, and students who have damage to memory centers in the brain end up in the sleep-deprived group. If this happened, your results might have more to do with unique characteristics in your sample of participants (sample characteristics) than with the effects of sleep deprivation. To identify your participants’ learning and memory abilities, it is best to give them a baseline test before they complete your study.

It’s also important to keep track of whether participants were honest about following the sleep instructions you gave them. It might not be possible to have participants sleep in your laboratory. To know whether participants followed your instructions to sleep eight hours (the well-rested group) or one hour (the sleep-deprived group), you need to make sure they feel they can be honest without being punished. To put them at ease, you might let them know that if for some reason they were not able to follow the instructions, that they can complete the study at a different time.

Note that by randomly assigning participants to either the well-rested or the sleep-deprived condition, you control for many other possible confounding variables. With random assignment, each participant has the same chance of being assigned to each group. This should balance out any preexisting differences among your participants.

Click on "Video Hint" below to see a brief animation describing Random Assignment.

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Random Assignment:

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You may do better on the Quiz if you take notes while watching this video. Feel free to pause the video or re-watch it as often as you like.

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