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 research scenario presented focuses on investigating the functioning of the sense of smell during different stages of sleep. The researcher aims to determine the responsiveness to odors during various sleep stages using an experimental setup involving fragrance delivery and physiological measurements. In this context, various aspects of the research hypothesis, independent variable, dependent variables, and the study’s limitation will be discussed.
The research hypothesis in this study is that research participants will be less responsive to odors during stages 3 and 4 sleep (deep sleep) compared to the other stages of sleep. Thus, it is expected that the intensity of the stimulus required to elicit a response during deep sleep will be higher.
The independent variable in this study is the stages of sleep. The researcher is interested in comparing the responsiveness to odors across different sleep stages, with an emphasis on distinguishing stages 3 and 4 sleep (deep sleep) from stages 1, 2, and REM sleep (lighter sleep).
Type of Independent Variable:
The independent variable, stages of sleep, can be classified as a qualitative variable. Qualitative variables are non-numerical and involve categorical distinctions. In this case, the sleep stages are categorized as either stages 1, 2, 3, 4, or REM sleep. These categories do not possess a numerical value but rather represent distinct qualitative states.
Use of Multiple Dependent Variables:
Researchers may choose to use multiple dependent variables to gain a more comprehensive understanding of the phenomenon under investigation. In this study, the researcher employs multiple dependent variables: the participants’ heart rate and their response to the odor presentation. By assessing both physiological (heart rate) and behavioral (response to odor) aspects, the researcher can obtain a broader range of information about the participants’ reactions during different sleep stages.
Limitation of the Study:
One limitation of this study is the use of college students as participants. College students might not be representative of the general population in terms of their sleep patterns and responsiveness to odors during sleep. Additionally, using a specific fragrance (peppermint) as the odor stimulus may limit the generalizability of the findings to other odors. Therefore, caution should be exercised when extrapolating the results to the wider population.