A Randomized Controlled Ecological Momentary Intervention to Improve Digital Self-Regulation and Well-Being

Daily Metacognitive Awareness assesses the extent to which participants were consciously aware of their motivations and tendencies regarding recreational screen use on that day, which adapted from metacognitive awareness dimension in Metacognition about Regulating Recreational Screen Time Scale (McRST). Sample items include: "Today, I was aware of why I wanted to use my device for recreational purposes." Items are rated on a 5-point Likert scale (1 = strongly disagree to 5 = strongly agree). Higher scores indicate greater daily metacognitive awareness.

Daily Recreational Screen Time is assessed using both subjective self-reports and objective device-recorded data in order to enhance measurement validity and reduce recall bias. Recreational screen time is defined as non-work and non-study device use, including activities such as social media browsing, video streaming, gaming, and other entertainment-related engagement.

Metacognitive skills will be assessed using the Metacognition about Regulating Recreational Screen Time Scale (Mc-RST). The scale captures individuals' knowledge, beliefs, and perceived efficacy regarding their ability to regulate recreational screen use. Participants rated on a 5-point Likert scale, with higher scores indicating stronger metacognitive awareness and perceived regulatory capacity.

Daily Stress is assessed using brief items adapted to capture day-specific perceived stress. Participants indicate the extent to which statements such as "Today, I felt stressed," "Today, I felt overwhelmed," and "Today, I found it difficult to cope with daily demands" describe their experience. Responses are rated on a 5-point scale ranging from 1 (not at all) to 5 (very much), with higher scores indicating greater daily stress.

Daily Life Satisfaction captures participants' cognitive evaluation of their day. Participants respond to items such as "Overall, I was satisfied with today," "Today was close to my ideal day," and "I feel positive about how today went." Responses are rated on a 5-point scale ranging from 1 (strongly disagree) to 5 (strongly agree). Higher scores indicate greater daily life satisfaction.

Internet addiction will be measured using the revised Chinese Internet Addiction Scale (CIAS-R; Bai & Fan, 2005), which assesses core symptoms and related problems of excessive Internet use, including compulsive use, withdrawal, tolerance, interpersonal difficulties, and time management issues. Participants responded to items based on their experiences over the past year using a 4-point scale, with higher scores indicating greater levels of problematic Internet use.

Short-form video addiction will be assessed using the Bergen Short Video Addiction Scale (Qu et al., 2024), which captures key components of addictive behavior, including salience, mood modification, tolerance, withdrawal, conflict, and relapse. Items were rated on a 5-point frequency scale, with higher scores indicating more severe short-form video addiction.

Depressive symptoms will be measured using the Patient Health Questionnaire-9 (PHQ-9; Leung et al., 2020), which assesses the frequency of depressive symptoms over the past two weeks. Each item was rated on a 4-point scale, with higher total scores indicating more severe depressive symptoms.

Anxiety symptoms will be assessed using the Generalized Anxiety Disorder-7 scale (GAD-7; He et al., 2010), which evaluates the frequency of anxiety-related symptoms over the past two weeks. Items were rated on a 4-point scale, with higher scores indicating higher levels of anxiety.

Perceived stress will be measured using the Chinese version of the Perceived Stress Scale (CPSS; Yang & Huang, 2003), which assesses the extent to which individuals perceive their lives as unpredictable, uncontrollable, and overloaded. Participants rated items on a 5-point scale, with higher scores indicating higher perceived stress.

Self-control will be assessed using the Chinese version of the Self-Control Scale (SCS; Unger et al., 2016), which measures individuals' ability to regulate impulses and maintain goal-directed behavior. Items were rated on a 6-point scale, and higher average scores indicate stronger self-control capacity.

Life satisfaction will be measured using the Satisfaction with Life Scale (SWLS; Diener et al., 1985), which assesses global cognitive judgments of one's life satisfaction. Participants rated five items on a 7-point Likert scale, with higher scores indicating greater life satisfaction.

Fear of missing out (FoMO) will be assessed using a validated FoMO scale (Przybylski et al., 2013; Li et al., 2019), which captures individuals' anxiety related to missing rewarding experiences or social interactions. Items were rated on a 5-point scale, with higher scores indicating higher levels of FoMO.