Affect labeling and political polarization

Last registered on April 16, 2024


Trial Information

General Information

Affect labeling and political polarization
Initial registration date
April 04, 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
April 16, 2024, 11:16 AM EDT

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



Primary Investigator


Other Primary Investigator(s)

PI Affiliation

Additional Trial Information

Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Affect labelling, the process of putting feelings into words, has been shown to have a calming effect on the brain. This study examines the impact of affect labelling on political polarization over Covid-mitigation measures, an emotionally-charged topic that led to large differences of opinion. We conducted an online experiment in which participants in a treatment group, randomly assigned, underwent a questionnaire to label their feelings before reporting their opinions. We found that affect labeling reduced polarization for young individuals, up to the age of 29, a demographic characterized by intense emotional responses due to increased activity in the amygdala, the region of the brain whose activity is reduced by affect labeling.
External Link(s)

Registration Citation

Hemsley, Pedro and Lynda Pavão. 2024. "Affect labeling and political polarization." AEA RCT Registry. April 16.
Experimental Details


We assigned randomly two treatments to participants in this online experiment. The first one was an affect labeling questionnaire: during the experiment, subjects answered this questionnaire as a way to express emotions freely (that is, perform affect labeling). The second one was the presentation of a short text with referenced information about Covid-19 mitigation measures. Then all subjects stated their opinions about these measures. Participation was entirely online and whole process took less than five minutes.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Political polarization, measured as the absolute value of the distance from a participant's opinion about Covid-mitigation policies to a neutral position (zero) in a scale from -8 to 8.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
We conducted an online survey on September 23, 2021, with 600 participants from the United States, recruited from Amazon’s Mechanical Turk. The reward for participation was set at US$0.45. Respondents were not permitted to participate more than once and we only accepted workers who had previous experience and had at least a 90 percent approval rating. The questionnaire design and data collection from respondents were conducted through the Qualtrics platform.

The study began with participants answering socio-demographic questions via an online link. Next, they were informed that we could ask questions about the Covid-19 pandemic, an emotionally-charged topic that led to major differences of opinion. Participants were then randomly split into four groups: one control group and three treatment groups.

The first treatment group underwent an affect labeling questionnaire, designed for unrestricted emotional expression. This questionnaire combined items from various scales that assess emotional states (detailed in the appendix). The objective is to give participants a structured framework to identify and express their feelings, with simple implementation, taking around one minute to complete.

The second treatment group received referenced information about the effectiveness of social distancing and mask-wearing, including hyperlinked sources for reference. The third treatment group received both the referenced information and completed the affect labeling questionnaire, while the control group received neither.

Then all groups were directed to the concluding questions of the questionnaire and rated their agreement or disagreement on the efficacy of measures to control the spread of COVID-19 on a scale of -8 to 8. We choose this scale to have a natural center: zero.

Specifically, participants gave their opinions about the following statements:

1- Social distancing is a relevant measure to limit the spread of the coronavirus.
2- Wearing masks is a relevant measure to limit the spread of the coronavirus.
Experimental Design Details
Randomization Method
Randomization done online through the Qualtrics platform
Randomization Unit
Individual participant in an online experiment
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
600 individuals
Sample size: planned number of observations
600 individuals
Sample size (or number of clusters) by treatment arms
146 participants in treatment 1 only (affect labeling)
150 participants in treatment 2 only (referenced information)
150 participants in treatments 1 and 2
150 participants in the control group
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
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

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials