SAMPLE APA RESEARCH EXPERIMENT PAPER

Title: The Effects of Sleep Deprivation on Mood and Cognitive Performance

Student’s Name
Institutional Affiliation

Abstract
This study examined the effects of total sleep deprivation on mood and cognitive performance in college students. 24 participants (12 males, 12 females), ages 18-22, completed self-report measures of mood before and after a full night of monitored wakefulness in a sleep laboratory. Participants also completed tests of attention, working memory, and processing speed before and after the night of sleep deprivation. Results showed significant declines in all measures of cognitive performance from pre- to post-deprivation. Self-reported mood was also significantly more negative after being awake all night. Females reported larger declines in mood than males. The study provides further evidence that missing even one night of sleep can negatively impact both cognitive functioning and emotional well-being.

The Effects of Sleep Deprivation on Mood and Cognitive Performance
Sleep is a biological necessity for humans, and missing even a small amount of sleep can have negative consequences. Research has well documented the impacts of acute total sleep deprivation on domains such as attention, memory, and mood regulation (Lim & Dinges, 2010). Many college students regularly miss out on the recommended 7-9 hours of sleep per night due to heightened academic pressures and social activities (Hershner & Chervin, 2014). This has implications not only for students’ health and well-being but also for their academic performance. The current study examined the effects of a single night of total sleep deprivation on both cognitive performance and self-reported mood in a sample of college students.

Method

Participants
The participants were 24 college students (12 males, 12 females), recruited from psychology courses at a large urban university. Ages ranged from 18 to 22 years (M = 19.7, SD = 1.2). The majority (79%) identified as Caucasian, with smaller percentages identifying as African American (8%), Hispanic (8%), and Asian (4%). Participants were screened for any diagnoses of sleep, psychiatric, or neurological disorders. They were instructed to maintain a regular sleep-wake schedule in the week leading up to the study and to avoid caffeine and alcohol for 24 hours prior to testing. Participants provided informed consent and received course credit for their participation. The university’s institutional review board approved all study procedures.

Procedure and Measures
The study took place over two sessions approximately one week apart. In the first session, participants completed questionnaires about their typical sleep habits and provided demographic information. They also completed baseline measures of mood and cognitive performance.

For the sleep deprivation session, participants arrived at the sleep laboratory at their typical bedtime (between 10pm-12am). Polysomnography (PSG) equipment was attached to monitor their physiological sleep state throughout the night. Lights remained on, and participants were monitored continuously to ensure they remained awake. They engaged in sedentary activities like reading, board games, and DVDs to keep themselves entertained. At their usual wake time the next morning (between 7am-9am), PSG equipment was removed, and they completed post-deprivation measures identical to the baseline. This included self-report mood scales and computerized tests of attention, working memory, and processing speed.

The Profile of Mood States (POMS; McNair et al., 1971) questionnaire assessed changes in six mood dimensions: Tension-Anxiety, Depression-Dejection, Anger-Hostility, Vigor-Activity, Fatigue-Inertia, and Confusion-Bewilderment. Participants rated how well 65 adjectives described their current mood on a 5-point Likert scale from 0 (Not at All) to 4 (Extremely). Raw subscale scores were converted to T-scores for analysis.

Tests from the Cambridge Neuropsychological Test Automated Battery (CANTAB; Sahakian & Owen, 1992) evaluated three cognitive domains:

Attention – Rapid Visual Information Processing (RVP) tasks participants to detect sequences of digits. Outcome measures included hits, misses, and false alarms.

Working Memory – Spatial Working Memory (SWM) requires locating tokens across multiple boxes without returning to boxes already opened. Outcome measures were errors and strategy used.

Processing Speed – Simple Reaction Time (SRT) involves pressing a button in response to stimuli on screen. Outcome measures were latency and movement time.

The order of completion for mood scales and cognitive tests was counterbalanced across participants.

Data Analysis
All analyses were conducted using IBM SPSS Statistics version 27. Paired samples t-tests evaluated changes from baseline to post-deprivation on mood and cognitive performance measures. Gender differences in changes in mood were analyzed with independent samples t-tests. Cohen’s d provided an estimate of effect sizes. Statistical significance was set at p < .05. Results Mood Paired samples t-tests revealed significant declines from baseline to post-deprivation on all six POMS subscales: Tension-Anxiety t(23) = 4.81, p < .001, d = 1.0; Depression-Dejection t(23) = 3.21, p = .004, d = 0.66; Anger-Hostility t(23) = 3.19, p = .004, d = 0.65; Vigor-Activity t(23) = -4.14, p < .001, d = 0.85; Fatigue-Inertia t(23) = 4.31, p < .001, d = 0.88); Confusion-Bewilderment t(23) = 3.91, p = .001, d = 0.80. This indicates worsening mood across all dimensions measured after total sleep deprivation. Independent samples t-tests found the decline in Vigor-Activity was significantly greater for females (t(22) = 2.31, p = .03, d = 0.95) but no other gender differences emerged. Cognitive Performance Paired samples t-tests revealed significant decreases from baseline to post-deprivation on all measures of cognitive performance: Attention (RVP): Hits: t(23) = 2.70, p = .01, d = 0.55 Misses: t(23) = -2.82, p = .009, d = 0.58 False Alarms: t(23) = -2.48, p = .02, d = 0.51 Working Memory (SWM): Errors: t(23) = 2.97, p = .007, d = 0.61 Strategy: t(23) = -2.79, p = .01, d = 0.57 Processing Speed (SRT): Latency: t(23) = 2.79, p = .01, d = 0.57 Movement Time: t(23) = 2.98, p = .007, d = 0.61 This shows impairments in all domains of cognitive performance measured after total sleep deprivation. Discussion This study provides further evidence that missing even a single night of sleep can negatively impact both subjective mood and objective measures of cognitive functioning in healthy young adults. Participants reported significant worsening on all dimensions of mood assessed by the POMS questionnaire after being awake all night compared to their baseline. Scores declined on each subscale measuring increased negative affect such as anxiety, depression, anger, fatigue, and confusion. Consistent with previous research, females reported a larger decrease than males specifically on feelings of vigor and activity (Gay et al., 2004).