The effect of digital photo enhancement on trust and trustworthiness

Last registered on April 20, 2022


Trial Information

General Information

The effect of digital photo enhancement on trust and trustworthiness
Initial registration date
April 15, 2022

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
April 20, 2022, 4:46 PM EDT

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



Primary Investigator

Peking University

Other Primary Investigator(s)

Additional Trial Information

On going
Start date
End date
Secondary IDs
Prior work
This trial is based on or builds upon one or more prior RCTs.
Online interactions anchor on the creation and maintenance of individuals’ virtual profiles. As a critical component of virtual profiles, digital photos are subject to artificial enhancements and may deviate from individuals’ actual physical appearances. The ubiquitous adoption of digital photo enhancement applications may influence how individuals behave in online interactions. We study, with a controlled online experiment, how individuals’ trust and trustworthiness change after digitally enhancing their profile photos in an online experiment. Participants play the trust game (Berg et al. 1995) with players’ profile photos shown saliently on the game interface. Participants in the treatment group enhance their profile photos and use enhanced profile photos, which participants in the control group use original profile photos during the game. We ask the participants to complete a comprehensive posttest after the game. We compare the levels of trust and trustworthiness between treatment and control groups to show the main effect of digital photo enhancement. We intend to further analyze the potential gender difference, beauty premium, and mechanism in such effect.
External Link(s)

Registration Citation

Ma, Sijia. 2022. "The effect of digital photo enhancement on trust and trustworthiness." AEA RCT Registry. April 20.
Experimental Details


We use an online version of the trust game (Berg et al. 1995) to measure the levels of trust and trustworthiness of participants. Specifically, we build a website for participants to play the trust game with their profile photos shown saliently. After randomizing the participants to different game roles (senders and receivers), we then randomize them to treatment and control groups. Participants in the treatment group enhance their profile photos and use the enhanced photos during the game. Participants in the control group use the original photos during the game. We use API for participants to enhance their profile photos.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Trust and trustworthiness
Primary Outcomes (explanation)
We measure the levels of trust and trustworthiness of participants using the trust game (Berg et al. 1995). The investment amount of sender represents the level of trust, and the returning ratio of receiver represents the level of trustworthiness.

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
We study the impact of digital photo enhancement on individual behaviors in a trust game. The trust game, proposed by Berg et al. (1995), is a widely applied method to measure trust and trustworthiness in economic decisions. In our experiment, each sender is randomly paired with ten different receivers to play ten rounds of a one-shot game. At the beginning of each round, both the sender and the receiver are endowed with ten tokens. Each token is worth 1 RMB (0.15 USD). In each round, the sender can invest any number of tokens, from 0 to 10, to the receiver. Any amount sent will be tripled, and the receiver can return any number of tokens out of the tripled amount back to the sender.
We enrich the trust game with an AI photo enhancement module and design a single-factor randomized online experiment. The treatment differs in whether the participants enhance their profile photos and present themselves with the enhanced photos in the trust game. In the experiment, a participant creates a virtual account with an ID code. The participant needs to upload a profile photo that is saliently displayed to both players in the game. Participants are provided with an AI photo makeup module to enhance their uploaded photo. In the treatment group, participants can use the enhanced photos to present themselves in the trust game. In the control group, participants can only use their original profile photos in the game. The photo enhancement module uses the API for facial recognition and feature enhancements. The participants can adjust the brightness, the temperature, and the saturation to obtain better skin tones and create refined facial features. They can also smooth out wrinkles, improve eye colors, remove facial imperfections and apply a warm-glow filter. The default options of the module are set to make the profile photos significantly more appealing. Meanwhile, detailed instructions are given to the participants on how the module works.
The experimental procedure is as follows. Each participant needs to register an account with their names and phone numbers after arriving at the experiment webpage. In the recruitment, we make sure that no participants have previously engaged in similar experiments. After registration, the participant is directed to the detailed instructions on the rules of the trust game and takes a quiz to ensure complete understanding. The participant then creates a profile with a personal photo. We require that the profile photo be a clear headshot with a white background and no modifications. Participants with unqualified profile photos are excluded. After completing the profile, the participant is randomly assigned to one of the game roles (a sender or a receiver), and enters three rounds of trial games to get familiar with the game rules and interface. After the trial games, the participant is randomly assigned to the treatment and control groups. Participants in the treatment group use their enhanced photo but those in the control group can only use their original photos in their profile in the game.
Next, each participant plays ten rounds of the independent one-shot trust game with the assigned role (sender or receiver). Senders (participants assigned the sender role) decide the amount to be sent to the opponent, while receivers (participants assigned the receiver role) determine the amount to be returned to the opponent. Both the senders and the receivers make decisions by entering numbers in an online form. The players in each round are randomly assigned to play with a fictional opponent. Participants were unaware that their opponents were randomly drawn from a historical dataset (Eckel and Petrie 2011). Opponents’ profile photos are randomly set to be either original or enhanced. Finally, each participant confirms the total earnings and collects rewards after finishing a posttest. The post-experiment includes measurement scales for social presence (Khalifa and Shen 2004), trust propensity (Gefen and Straub 2004), risk attitude (Pennings and Smidts 2000), as well as trap questions, manipulation checks, and demographic questions. We use a seven-point Likert scale and randomize the items to avoid potential order effects.
Experimental Design Details
Randomization Method
Randomization done by a computer.
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
200 individuals
Sample size: planned number of observations
1000 sender observations and 10000 receiver observations.
Sample size (or number of clusters) by treatment arms
50 in each group (sender treatment, sender control, receiver treatment, receiver control)
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
Peking Behavioral Lab
IRB Approval Date
IRB Approval Number


Post Trial Information

Study Withdrawal

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Is the intervention completed?
Data Collection Complete
Data Publication

Data Publication

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Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials