Does switching to a grayscale phone screen reduce phone usage?
The rise of smartphones and continuous connectivity has given way to what some describe as “compulsive” use. This has been purported to yield negative outcomes in terms of productivity, such diminished attention spans, due to frequent interruptions.
Researchers have also found smartphone use to have detrimental effects on enjoyment of face-to-face interactions and the associated mental health benefits of social connections: popular media coverage has often focused on the damaging effects of smartphones among youth users, with sensationalist headlines such as “Have Smartphones Destroyed a Generation?”
This technology backlash has led to the emergence of the “digital wellness” movement, pioneered by the Center for Humane Technology, which aims to “realign technology with humanity’s best interests.
With the new availability of usage data, we decided to examine the effect of a grayscale screen, which – before the advent of Digital Wellbeing and Screen Time features – had gained traction as a way to limit smartphone “addiction”
The experiment took place over the course of two weeks, from November 5th to 19th, 2018, with 21 participants. It was preceded by a three-day pilot with four different participants, from October 31st to November 2nd. Participants were split into two groups, R1 and R2, to designate assignment to treatment or control per day (Table 1).
Each subject was assigned both treatment and control on each day of the week, with half having treatment both at the beginning and end of the study (R1) while the other half had consecutive days in the middle (R2). The experiment design was intended to allow for both analysis of within subjects and across subjects comparisons. Screen time measurements occurred on Mondays, given that our data source, the Apple Screen Time app, only retains data for seven days.
Treatment. Subjects in treatment were asked to switch their phones into grayscale mode via text message in the morning. Upon first treatment assignment, participants were provided instructions on how to access this mode in their settings.
Participants were then asked for a screenshot of the weather to ensure compliance. In our pilot study, we came to learn that even if the participant is in grayscale, the screenshot sent does not render in grayscale; however, we still retained responsiveness to the researcher as a proxy for compliance.
Analysis & Results
In order to analyze the impact of grayscale on screen time usage we ran a Panel OLS regression as well as clustered and non-clustered OLS regressions to measure the treatment effect. Panel OLS allows us to look at observations across time but within each specific individual. Since we can think about individuals as different in this model we can remove unobserved heterogeneity.
Therefore, we can disregard that there are differences in average levels of screen time usage between individuals and assume that the differences are due to individual specific characteristics that don’t change over time.
Finally, we implemented clustered OLS regression (clusters are based on treatment assignment, meaning each individual contained 4 clusters given they experienced treatment twice and control twice) because we felt the potential outcomes would be similar within each cluster given that treatment or control occurred over a three-day period.
While our hypothesis predicted that grayscale would negatively impact screen time, our findings actually suggest no treatment effect after adding in covariates and clustering at the individual level.