Mindless Entry or Timeless Engagement? An Experimental Study on Strategies to Reduce Screen Time

Last registered on October 29, 2025
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Pre-Trial

Trial Information

General Information

Title
Mindless Entry or Timeless Engagement? An Experimental Study on Strategies to Reduce Screen Time
RCT ID
AEARCTR-0015364
Initial registration date
June 17, 2025

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
June 20, 2025, 11:41 AM EDT

First published corresponds to when the trial was first made public on the Registry after being reviewed.

Last updated
October 29, 2025, 11:58 AM EDT

Last updated is the most recent time when changes to the trial's registration were published.

Locations

Country
Germany
Region

Primary Investigator

Name
Anna Popova
Affiliation
LMU Munich
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Other Primary Investigator(s)

PI Name
David Grüning
PI Affiliation
Center for Adaptive Rationality, Max Planck Institute for Human Development; Mussallem Center for Biodesign, Stanford University
Contact Investigator

Additional Trial Information

Status
In development
Start date
2025-11-16
End date
2025-12-21
Keywords
Behavior, Other
Additional Keywords
social media, field experiment
JEL code(s)
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
Excessive usage of smartphones poses significant challenges with adverse welfare implications, yet complete restriction is neither feasible nor desirable. This study investigates screen time consumption patterns and the effectiveness of various interventions to reduce excessive smartphone usage. Partnering with one sec, an app that aids in screen time consumption regulation, I conduct a randomized controlled trial (RCT) involving new users to examine pre-entry, post-entry, and combined interventions. The study consists of three phases over four weeks: baseline survey, randomized treatment assignment, and an end-line survey. Key research questions explore the prevalence and interactions of consumption patterns, as well as the intervention adherence and efficacy. By examining the patterns of screen time consumption and testing different interventions to reduce it sustainably, this research project aims to contribute to the behavioral economics literature on commitment devices, digital consumption, and inform more effective policy recommendations.
External Link(s)

Registration Citation

Citation
Grüning, David and Anna Popova. 2025. "Mindless Entry or Timeless Engagement? An Experimental Study on Strategies to Reduce Screen Time." AEA RCT Registry. October 29. https://doi.org/10.1257/rct.15364-1.5
Sponsors & Partners

Partner

Name
Type
private_company
URL
https://one-sec.app
Experimental Details

Interventions

Intervention(s)
The intervention compares the usage of a targeted (chosen) digital app between the control and three treatment groups. The pre-entry treatment group introduces a delay in access to the targeted app, while the post-entry intervention introduces a delay in the ability to continue using the app after a pre-set amount of time has passed. Pre- and post-entry interventions refer to the timing of when the interventions are triggered. The third intervention is a combination treatment that includes both pre- and post-entry interventions.
Intervention (Hidden)
Participants choose one app whose consumption they want to reduce the most. They are then randomly assigned to either the control group or one of three treatment groups. The difference between interventions lies in the timing of when, within the consumption timeline, the intervention is triggered.

The pre-entry intervention is triggered when the participant attempts to open the targeted app. Immediately after attempting to open the app, participants are sent to the intervention screen, which delays access to the app by five seconds. The intervention cannot be skipped, so if the participant wants to open the targeted app, they must wait five seconds. They can also choose to close the app immediately or wait five seconds before deciding to close it.

The post-entry intervention is triggered after the participant enters the targeted app and spends a pre-defined amount of time there (this goal time is collected in the baseline survey). The intervention functions exactly like the pre-entry intervention. After the intervention screen, the participant can choose to stay on the app (after the five-second delay) or leave it.

The combination intervention simply includes both pre-entry and post-entry interventions.
Intervention Start Date
2025-11-16
Intervention End Date
2025-12-21

Primary Outcomes

Primary Outcomes (end points)
The main outcomes of interest are the three dimensions of digital consumption: overall daily screen time consumption (measured in hours); daily app entry frequency (how many times the participant attempted and opened the app); average per-entry consumption duration (in minutes) and intervention adherence (dropout rates across groups).
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary outcomes include a change in consumption patterns between treatments, naivete about consumption patterns, ideal time achievements, and spillover to other application usage.
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
A four-week field experiment on screen time consumption (with an emphasis on social media) tests the efficacy of pre- and post-entry interventions. Participants are recruited from the pool of new users of the one sec app. After completing the baseline survey, they are randomized into either the control group or one of three treatment groups.
Experimental Design Details
The experiment consists of three blocks and lasts approximately four weeks.

First, we recruit new users of OneSec to participate in the study, offering a premium subscription as an incentive. The second part is treatment randomization. Twenty-five percent of participants are assigned to the control group, while the remaining participants are randomized into one of three treatment groups. OneSec offers three interventions: pre-entry, post-entry, and a combination of both. The treatment period lasts four weeks. The final part of the experiment is the endline survey, which assesses satisfaction with consumption, perceptions of consumption changes, and potential spillover effects, including other app usage, mental health, and work/study satisfaction.
Randomization Method
Computer randomisation
Randomization Unit
Individual
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
1600 participants
Sample size: planned number of observations
around 45,000 minus attrition
Sample size (or number of clusters) by treatment arms
400
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
Ethics Commission, Department of Economics, University of Munich
IRB Approval Date
2025-03-20
IRB Approval Number
N/A
Analysis Plan

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Post-Trial

Post Trial Information

Study Withdrawal

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Intervention

Is the intervention completed?
No
Data Collection Complete
Data Publication

Data Publication

Is public data available?
No

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials