An interventional study of Ecological momentary intervention in Behavioral Self-monitoring and Metacognitive Reflection, sponsored by The Hong Kong Polytechnic University. Recruiting at 1 site in Hong Kong. Open to participants aged 18 Years to 25 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-04-06.
Sponsored by The Hong Kong Polytechnic University · Not applicable, Interventional, and Prevention
The primary objective of this study is to examine whether an ecological momentary intervention (EMI), combining behavioral self-monitoring (screen time screenshot uploads) and structured reflection, can enhance metacognitive awareness and metacognitive regulation in the context of recreational screen time among young adults.
A secondary objective is to investigate whether improvements in metacognitive processes are associated with subsequent changes in behavioral and psychological outcomes, including recreational screen time (RST), stress, and life satisfaction.
Furthermore, this study aims to elucidate the underlying mechanisms through which the intervention exerts its effects by integrating a randomized controlled trial (RCT) design with intensive longitudinal (daily diary) data.
Specifically, the study addresses the following research questions:
RQ1 (Primary Intervention Effect on Metacognition): Does the EMI lead to higher levels of daily metacognitive awareness and metacognitive regulation (planning, monitoring, and evaluation) compared to the control group? RQ2 (Within-person Associations): At the within-person level, do day-to-day fluctuations in metacognitive awareness and regulation predict same-day and next-day changes in recreational screen time, stress, and life satisfaction? RQ3 (Mediating Mechanism): Do increases in metacognitive awareness and regulation mediate the effects of the EMI on recreational screen time, stress, and life satisfaction? RQ4 (Between-person Effects): At the between-person level, do individuals in the intervention group exhibit higher average levels of metacognitive awareness and regulation, as well as lower recreational screen time and stress and higher life satisfaction, compared to those in the control group?
168 studies on the registry are indexed under Self-Control; 22 are open to participants now.
This study's planned enrollment of 240 is above the median of 88 across 144 interventional studies indexed under Self-Control.
Browse Self-Control studies →The Hong Kong Polytechnic University is the lead sponsor of 679 studies on the registry; 257 are open to participants now.
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Participants must meet all of the following criteria:
Exclusion Criteria:
Participants in the intervention group will receive a composite ecological momentary intervention that integrates behavioral self-monitoring and metacognitive reflection. Specifically, each day participants will: 1. Upload a screenshot of their device-recorded screen time (e.g., iOS Screen Time or Android Digital Wellbeing), serving as a form of behavioral self-monitoring. 2. Complete structured reflection prompts designed to activate metacognitive processes, including reflection on: (1) total recreational screen time, (2) usage contexts (e.g., situations or triggers), (3) awareness of potential overuse, and (4) use of regulation strategies (e.g., planning, monitoring, evaluation). In addition, participants will complete daily measures of metacognitive awareness, metacognitive regulation, stress, and life satisfaction.
Behavioral: Ecological momentary intervention
Participants in the control group will complete the same daily diary measures of metacognitive awareness, metacognitive regulation, stress, and life satisfaction, but will not engage in screen time self-monitoring (i.e., no screenshot uploads) and will not receive any structured reflection prompts.
A composite ecological momentary intervention that integrates behavioral self-monitoring and metacognitive reflection. Specifically, each day participants will: 1. Upload a screenshot of their device-recorded screen time (e.g., iOS Screen Time or Android Digital Wellbeing), serving as a form of behavioral self-monitoring. 2. Complete structured reflection prompts designed to activate metacognitive processes, including reflection on: (1) total recreational screen time, (2) usage contexts (e.g., situations or triggers), (3) awareness of potential overuse, and (4) use of regulation strategies (e.g., planning, monitoring, evaluation).
Daily Metacognitive Awareness
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.
Time frame: 14-day dairy
Daily Recreational Screen Time
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.
Time frame: 14-day dairy
Metacognitive skills
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.
Time frame: baseline, day 15 (t1)
Daily Stress
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.
Time frame: 14-day dairy
Daily Life Satisfaction
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.
Time frame: 14-day dairy
Internet addiction
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.
Time frame: baseline, day 15 (t1)
Short-form video addiction
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.
Time frame: baseline; day 15(t1)
Depressive symptoms
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.
Time frame: baseline; day 15(t1)
Anxiety 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.
Time frame: baseline; day 15(t1)
Perceived stress
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.
Time frame: baseline; day 15(t1)
Self-control
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.
Time frame: baseline; day 15(t1)
Life satisfaction
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.
Time frame: baseline; day 15(t1)
Fear of missing out (FoMO)
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.
Time frame: baseline; day 15(t1)
Plan to share: No — Individual participant data (IPD) will not be publicly shared due to the sensitive nature of the data, which includes detailed daily behavioral records and potentially identifiable digital usage patterns. Although all data will be de-identified, the granularity of longitudinal diary data and screen time records may still pose a risk of re-identification. In addition, data sharing is restricted by institutional ethical approval and participant consent agreements, which limit the use of the data to the current research purposes only. Aggregated data and study materials can be made available upon reasonable request.
Started Mar 2026 (actual). Primary completion is estimated for May 2026, 2 months after the start.
Of 104 non-industry interventional studies with no phase under Self-Control, half reached primary completion within 16 months of starting (the median), counting those still running; a quarter within 5 and three quarters within 34. This study's planned 2 months is below that.
Counting every sponsor, half of 105 studies reached it within 16 months; a quarter within 5 and three quarters within 34.
How these figures are worked out, and which studies are left out of them.
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