Sleep hygiene and He et al. (2020): WACE Year 12 Psychology Unit 4

What this dot point is asking

He et al. (2020) is a designated study, so you need its aim, method, key findings, contribution to psychology and limitations. The study is also an excellent example for Science inquiry questions on design, variables, measures and ethics.

Techniques to improve sleep hygiene

Management of electronic devices

• Stop using phones, tablets, laptops and games at least 30 to 60 minutes before bed.
• Keep devices out of the bedroom or out of reach, and turn off notifications.
• Why it helps: screens are mentally arousing (messages, social media, games), delay bedtime, and their bright light in the evening can delay the body's natural signals for sleep.

Consistent sleep patterns

• Go to bed and wake up at the same time every day, including weekends.
• Avoid long daytime naps late in the day.
• Why it helps: a regular schedule keeps the body clock stable, so you feel sleepy and wake up at predictable times.

Creation of a healthy sleep environment

• Keep the bedroom dark, quiet, cool and comfortable.
• Use the bed only for sleep, not for study or screens.
• Why it helps: fewer disturbances, and the bedroom becomes associated with sleep.

Designated study: He et al. (2020)

Aim. To test whether restricting mobile phone use before bedtime would improve sleep, reduce pre-sleep arousal, and improve mood and working memory in college students with poor sleep quality.

Method.

• Design: a randomised controlled trial (an experiment with random allocation) lasting four weeks.
• Participants: 38 college students in China with poor sleep quality who used a mobile phone for more than 30 minutes at bedtime; people with depression, sleep disorders, sleep medication use or high caffeine or alcohol intake were excluded.
• Groups: an intervention group (19) was asked not to use their phone in the 30 minutes before bed; a control group (19) was given no instructions.
• Measures (before and after): a sleep diary (time to fall asleep, sleep duration); the Pittsburgh Sleep Quality Index (sleep quality); the Pre-sleep Arousal Scale (cognitive and physical arousal); the Positive and Negative Affect Schedule (mood); and an n-back task (working memory accuracy and reaction time).
• Ethics: approved by an ethics committee; written informed consent was obtained.

Key findings. Compared with the control group, the intervention group:

• fell asleep faster (sleep latency shorter by about 12 minutes) and slept longer (about 18 minutes more);
• had better sleep quality scores;
• had lower pre-sleep arousal, both cognitive and physical;
• had more positive mood (the drop in negative mood was not statistically significant);
• improved working memory, with higher accuracy on the 1-back and 2-back tasks and faster reaction times on the easier versions.

Contribution. It provides experimental evidence, not just correlations, that reducing bedtime phone use improves sleep and daytime functioning, supporting sleep hygiene advice about managing devices.

Limitations.

• Small sample (38), so the results need to be confirmed in larger studies; the authors describe it as a pilot trial.
• Generalisability: the participants were motivated college students with poor sleep, so the results may not apply to other groups such as younger teenagers or people unwilling to change.
• Self-report measures: sleep diaries and questionnaires are subjective; objective measures of sleep would strengthen the findings.
• Short duration: four weeks does not show whether the benefits last.