Replacing Humans by Robots: An Experiment on Perceived Trustworthiness

Last registered on May 22, 2024


Trial Information

General Information

Replacing Humans by Robots: An Experiment on Perceived Trustworthiness
Initial registration date
May 17, 2024

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
May 21, 2024, 11:33 AM EDT

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

Last updated
May 22, 2024, 7:04 AM EDT

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



Primary Investigator

University of Zurich

Other Primary Investigator(s)

PI Affiliation
University of Zurich
PI Affiliation
University of Zurich
PI Affiliation
Osaka University

Additional Trial Information

In development
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
We investigate how robots influence perceived trustworthiness in various scenarios, including hotels, restaurants, and dental clinics. Our study examines the impact of mechanical and thinking/feeling tasks performed by robots on customer perceived trustworthiness. Additionally, we assess whether enhancements in a robot's physical appearance, exemplified by the Tesla robot, and the presence of human supervision can improve perceptions of tasks rendered by robots. In this analysis plan, we pre-register the experimental framework we will follow.
External Link(s)

Registration Citation

Clochard, Gwen-Jiro et al. 2024. "Replacing Humans by Robots: An Experiment on Perceived Trustworthiness." AEA RCT Registry. May 22.
Experimental Details


We perform three experiments with Prolific Online workers to examine how customers' perceived trustworthiness is influenced by robots. Additionally, we test whether enhancements in physical appearance and human supervision moderate the effect.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
The main variable of interest is the overall perceived trustworthiness.
Primary Outcomes (explanation)
We measure overall satisfaction using a 7-point Likert scale. Participants strongly agree/disagree with the following statement:
"Overall, I find restaurant/hotel/dental clinic to be trustworthy".

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
In Study 1, participants view daily life videos depicting three scenarios, i.e., dental clinic, restaurant, and hotel, where humans perform mechanical and feeling/thinking tasks. We investigate participant perceptions of trustworthiness when robots replace humans performing these tasks. We examine three robot conditions (between-subjects): Mechanical robots (Robots perform mechanical tasks) vs. Feeling/thinking robots (robots perform feeling/thinking tasks) vs. All-Robots (Robots perform both tasks)

In Study 2, we replace the Pepper robot from Study 1 with a more technologically advanced Tesla robot to examine if superior aesthetics enhance perceived trustworthiness.

In Study 3, we extend the scenario description from Study 1, informing participants that robots are working under staff supervision. This information element assesses the impact of human supervision on perceived trustworthiness.
Experimental Design Details
Randomization Method
Our experimental framework employs a 3 (robot condition, between-subjects: Mechanical Robots vs. Thinking/Feeling Robots vs. All-Robots) by 3 (scenario video, within-subjects: Hotel vs. Restaurant vs. Dental Clinic) mixed design across three studies. Participants are randomly assigned to Study 1, 2, or 3, and then randomly assigned to one of the three robot conditions, in which they are presented with three scenario videos.
Randomization Unit
Participant level.
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
Our study does not involve clusters; participants are individually assigned to different treatment conditions.
Sample size: planned number of observations
2000 participants
Sample size (or number of clusters) by treatment arms
800 participants in Study 1 (Pepper Robot, No Human Supervision)
600 participants in Study 2 (Tesla Robot, No Human Supervision)
600 participants in Study 3 (Pepper Robot, With Human Supervision)
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Study 1 enables the detection of an effect size of 0.017 with 80% power at an alpha level of 0.01 in a linear regression with 9 predictors. Study 2 enables the detection of an effect size of 0.017 with 80% power at an alpha level of 0.01 in a linear regression with 13 predictors. Study 3 enables the detection of an effect size of 0.017 with 80% power at an alpha level of 0.01 in a linear regression with 13 predictors.

Institutional Review Boards (IRBs)

IRB Name
The Human Subjects Committee of the Faculty of Economics, Business Administration and Information Technology at the University of Zurich
IRB Approval Date
IRB Approval Number
OEC IRB # 2024-047
Analysis Plan

Analysis Plan Documents

Pre-Analysis Plan

MD5: fff49cbb20d496fc9d58e7a7a5536607

SHA1: 39b0109c7def801542ea670147804acc37f4ed5a

Uploaded At: May 22, 2024


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Is the intervention completed?
Data Collection Complete
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials