Overview

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?

Eligibility

Inclusion Criteria:

Participants must meet all of the following criteria:

1. Age between 18 and 25 years old.
2. Own and regularly use a smartphone.
3. Report an average daily recreational screen time of at least 3 hours on weekdays or 4 hours on weekends, based on self-report (Zablotsky et al., 2025).
4. Be able to access their device's built-in screen time tracking function (or equivalent system-level usage report) and upload screenshots when required.
5. Be willing and able to complete daily surveys throughout the full study period.
6. Indicate motivation to reduce or regulate their recreational screen use.

Exclusion Criteria:

1. Outside the age range of 18-25 years.
2. Do not own a smartphone or do not use it regularly.
3. Report average daily recreational screen time below 3 hours on weekdays and below 4 hours on weekends.
4. Are unable to access device-based screen time tracking functions or cannot provide valid screenshots when required.
5. Are unwilling or unable to complete daily surveys across the study period (e.g., anticipated non-compliance, scheduling constraints).
6. Do not express motivation to reduce or regulate their recreational screen use.