AP Psychology FRQ Practice

🧠AP Psychology

Guided Practice

Practice FRQ 1 of 211/21

Using the source provided, respond to all parts of the question.

1. Your response to the question should be provided in six parts: A, B, C, D, E, and F. Write the response to each part of the question in complete sentences. Use appropriate psychological terminology in your response.

A. Identify the research method used in the study.

B. State the operational definition of stress levels in the study.

C. Explain what the correlation coefficient indicates about the relationship between sleep duration and stress levels.

D. Identify at least one ethical guideline applied by the researchers.

E. Explain the extent to which the research findings may or may not be generalizable using specific and relevant evidence from the study.

F. Explain how the research findings support or refute the restorative theory of sleep.

Introduction

AI generated

Sleep researchers have long sought to understand how sleep duration relates to physiological indicators of stress in the body. Drawing on the restorative theory of sleep, which posits that sleep serves to repair and rejuvenate bodily systems depleted during waking hours, the present study investigated whether individuals who obtain more sleep each night exhibit lower levels of the stress hormone cortisol. Understanding this relationship may provide insight into the biological mechanisms through which inadequate sleep affects physical health.

Total N: 342
Recruitment: Participants were recruited through flyers posted in residence halls and student centers at three large public universities in the Midwestern United States. Students who expressed interest completed an online screening questionnaire to confirm eligibility (enrolled full-time, no diagnosed sleep disorders, not currently taking corticosteroid medications).
Gender: 58.2% women, 39.5% men, 2.3% non-binary or other gender identities¹
Race/Ethnicity: 61.4% White, 14.9% Asian, 11.1% Black or African American, 8.5% Hispanic or Latino, 4.1% multiracial or other
Age Range: 18-24 years
Age Mean: 19.8
Age SD: 1.4
Compensation: Participants received a $25 gift card upon completion of the 14-day study protocol

Electronic Sleep Log Application: A smartphone-based application developed for this study that prompted participants each morning to record their bedtime and wake time from the previous night. The application automatically calculated total sleep duration in hours and minutes.
Salivette Cortisol Collection Kits: Standardized saliva collection devices consisting of a cotton swab held in the mouth for two minutes. Participants received 14 individually labeled kits with detailed collection instructions.
Pittsburgh Sleep Quality Index (PSQI): A 19-item self-report questionnaire measuring sleep quality and disturbances over the past month, used to characterize the sample's general sleep patterns.
Perceived Stress Scale (PSS-10): A 10-item measure assessing subjective stress levels over the past month, included as a covariate.

Interested students attended an initial orientation session where researchers explained the study purpose and procedures. Participants provided written informed consent after having the opportunity to ask questions and being reminded that participation was voluntary and they could withdraw at any time without penalty.
Participants completed baseline questionnaires including the PSQI, PSS-10, and a demographic survey. Researchers then trained participants on using the electronic sleep log application and collecting saliva samples.
Over the following 14 consecutive days, participants recorded their sleep duration each morning using the smartphone application within 30 minutes of waking. They also collected a saliva sample immediately upon waking, before eating, drinking, or brushing teeth, by placing the cotton swab in their mouth for two minutes.
Participants stored saliva samples in their home freezers and returned them to the laboratory in an insulated cooler bag on days 7 and 14. Researchers verified sample quality and checked compliance with the sleep log.
Saliva samples were analyzed using enzyme-linked immunosorbent assay (ELISA) to determine cortisol concentrations in nanomoles per liter (nmol/L). Average cortisol levels across the 14 days were calculated for each participant.
Average nightly sleep duration was computed for each participant based on their 14-day sleep log data. All participants were debriefed about the study hypotheses upon completion and given an educational handout about healthy sleep practices.
To ensure confidentiality of physiological data, all saliva samples and cortisol results were labeled with participant ID numbers only, and the linking file connecting IDs to names was stored on a password-protected computer accessible only to the principal investigator.

Salivary cortisol levels were operationally defined as the average concentration of cortisol measured in nanomoles per liter (nmol/L) across all morning saliva samples collected during the 14-day study period, as determined by ELISA analysis. Sleep duration was operationally defined as the average number of hours slept per night, calculated from participant-reported bedtimes and wake times recorded in the electronic sleep log over 14 consecutive days.

Confidentiality of physiological data was maintained by assigning each participant a unique identification number; all biological samples and cortisol results were labeled only with this ID number, and the master file linking IDs to participant names was stored on a secure, password-protected computer with access restricted to the principal investigator.

Results revealed a statistically significant negative correlation between average nightly sleep duration and salivary cortisol levels (r = -.38, p < .01), indicating that participants who slept more hours per night tended to have lower cortisol concentrations upon waking. Additionally, sleep duration was positively correlated with sleep quality (r = .44, p < .01) and negatively correlated with perceived stress (r = -.29, p < .01). Cortisol levels showed a moderate positive correlation with perceived stress scores (r = .51, p < .01).

Variable	1	2	3	4
1. Average Sleep Duration (hours)	—	-.38**	.44**	-.29**
2. Salivary Cortisol (nmol/L)	-.38**	—	-.26**	.51**
3. Sleep Quality (PSQI)²	.44**	-.26**	—	-.33**
4. Perceived Stress (PSS-10)	-.29**	.51**	-.33**	—

The findings support the hypothesis that longer sleep duration is associated with lower physiological stress markers, as evidenced by the significant negative correlation between hours of sleep and morning cortisol levels. These results align with the restorative theory of sleep, which proposes that sleep allows the body to recover from daily wear and repair biological systems, including regulation of the hypothalamic-pituitary-adrenal axis that controls cortisol release. However, because this was a correlational study, we cannot determine whether insufficient sleep causes elevated cortisol, whether high stress and cortisol levels disrupt sleep, or whether a third variable such as academic workload influences both; future experimental research manipulating sleep duration would be needed to establish causality. Furthermore, the sample was limited to undergraduate students aged 18-24 from three Midwestern universities, which restricts generalizability to older adults, non-college populations, and individuals from other geographic regions.

Martinez, R. J., Chen, S. L., & Thompson, K. A. (2022). Sleep duration and cortisol awakening response in college students: A correlational investigation. Journal of Health Psychology, 27(4), 891–904. https://doi.org/10.1177/13591053211024872

1. Gender categories reflect participant self-identification. Terminology follows current APA guidelines for reporting demographic characteristics.

2. PSQI scores are reverse-coded such that higher scores indicate better sleep quality, consistent with recent scoring recommendations. Original PSQI scoring uses lower scores to indicate better quality.