Scenarios:A researcher wonders how well the sense of smell functions during sleep. In general, we know that our sensory systems operate at a higher threshold during sleep. That is, a more intense stimulus is required to elicit a response during sleep than during wakefulness. Furthermore, we are less responsive during some stages of sleep than during others. Experiments using sounds suggest that we are less responsive during stages 3 and 4 sleep (deep sleep) than during stages 1, 2, or REM sleep (lighter sleep). Thus, the 4 – 16 researcher predicts that research participants will be less responsive to odors during stages 3 and 4 sleep than during the other stages of sleep. The researcher devises a system for delivering odors while college students sleep in the laboratory. Peppermint fragrance is delivered at specific times through a modified oxygen mask that the students wear while they sleep. Electrodes are attached to each student’s scalp, face, and chin to determine sleep staging. Electrodes are also attached to each student’s chest to record heart rate. A change in heart rate following presentation of the odor is used to indicate that the participant detected the odor. Read the scenario above and answer the following questions: What is the research hypothesis? What is the independent variable? Is the independent variable a qualitative variable or a quantitative variable? Explain. Why might the researchers want to use multiple dependent variables? Describe one limitation of this study.
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The researcher in this scenario is interested in investigating how the sense of smell functions during sleep. They aim to explore the responsiveness of individuals to odors during different stages of sleep using a modified oxygen mask to deliver peppermint fragrance and monitoring the participants’ sleep staging and heart rate. In this context, we will address several key questions related to this research scenario.
1. What is the research hypothesis?
The research hypothesis in this study is that research participants will be less responsive to odors during stages 3 and 4 sleep (deep sleep) than during stages 1, 2, or REM sleep (lighter sleep).
2. What is the independent variable?
The independent variable in this research scenario is the stage of sleep. The researcher is manipulating the stages of sleep in order to observe any differences in responsiveness to odors among these stages.
3. Is the independent variable a qualitative variable or a quantitative variable? Explain.
The independent variable, the stage of sleep, can be considered as a qualitative variable. This is because the stages of sleep (1, 2, 3, 4, and REM) represent discrete categories or conditions that are not directly measurable on a numerical scale. Each stage of sleep is characterized by its unique features, and the researcher is interested in comparing these distinct stages rather than quantifying the stages themselves.
4. Why might the researchers want to use multiple dependent variables?
The researchers might choose to use multiple dependent variables to obtain a more comprehensive understanding of the participants’ responsiveness to odors during sleep. By monitoring both the sleep staging (using electrodes attached to the scalp, face, and chin) and heart rate (using electrodes attached to the chest), the researchers can gather different types of physiological data. This approach allows for a more thorough assessment of the participants’ responses to the odors presented during different stages of sleep.
5. Describe one limitation of this study.
One limitation of this study could be the use of a single odor (peppermint fragrance) as the stimulus. Different individuals may have varying sensitivities or preferences for different odors. Therefore, the use of multiple odors could provide a more comprehensive understanding of the generalizability of the findings. Additionally, the possibility of habituation or desensitization to a single odor over time could influence participants’ responsiveness. Therefore, using different odors could help address this potential limitation and enhance the validity of the results.