Evaluating Causal Claims Regarding Blue Light and Sleep
Causal claim: When people use their phone or laptop in bed before falling asleep, blue light from the phone causes them to have trouble falling asleep. You can avoid this outcome by switching your phone to night mode or night shift, so that the phone screen emits much less blue light.
Read the following two articles.
Newsom and Singh:
Reynolds:
In a maximum of 400 words, answer all of the following questions.
1) Do Newsom and Singh accept the causal claim above? Does Reynolds? Who do you think is right? Explain why.
2) Does Reynolds think that exposure to bright light has some effect on sleep?
3) Using the terminology that we used in class, describe an experiment that you would design to test whether blue light from phones does cause people to have trouble falling asleep.
Evaluating Causal Claims Regarding Blue Light and Sleep
1) Acceptance of the Causal Claim
Newsom and Singh accept the causal claim that blue light emitted from phones and laptops can cause difficulties in falling asleep. They argue that exposure to blue light inhibits melatonin production, a hormone crucial for regulating sleep cycles. On the other hand, Reynolds is more skeptical about the direct causal link between blue light exposure from screens and sleep disturbances. Reynolds suggests that while blue light may play a role, other factors, such as overall screen time and content consumed before bedtime, also contribute to sleep issues.
I find Newsom and Singh's position more compelling because numerous studies have shown that blue light suppresses melatonin production more than other wavelengths of light. This biological mechanism provides a strong basis for their claim. However, I also recognize the importance of considering additional factors mentioned by Reynolds, as they can compound the effects of blue light.
2) Reynolds' View on Bright Light Exposure
Reynolds does believe that exposure to bright light has an effect on sleep. He acknowledges that bright light can disrupt circadian rhythms, indicating that it may interfere with sleep patterns. However, he emphasizes that the complexity of sleep issues cannot be solely attributed to blue light from screens. Instead, he suggests a broader perspective that considers various environmental and behavioral factors.
3) Experiment Design to Test Blue Light's Impact on Sleep
To test whether blue light from phones causes trouble in falling asleep, I would design a randomized controlled trial with the following components:
Participants
- Recruit 100 adult volunteers who report using their phones before bed.
Groups
- Randomly assign participants into two groups: - Control Group: Participants use their phones with standard settings (emitting blue light) for 30 minutes before bedtime.
- Experimental Group: Participants use their phones set to "night mode" or "night shift," which reduces blue light emission for the same duration.
Procedure
1. Pre-Sleep Questionnaire: Have participants fill out a questionnaire assessing their baseline sleep quality and habits.
2. Intervention: Both groups will use their phones for 30 minutes prior to bedtime, engaging in similar activities (e.g., reading articles, browsing social media).
3. Sleep Monitoring: Use wrist actigraphy or sleep diaries to track sleep onset latency (the time it takes to fall asleep) and overall sleep quality for one week.
Data Analysis
- Compare the average sleep onset latency and quality between the two groups using statistical methods to determine if there is a significant difference in sleep outcomes due to blue light exposure.
This experiment would help clarify the causal relationship between blue light from screens and difficulties in falling asleep by controlling for other potential confounding factors.