Persuasion and Gender: Experimental Evidence from Three Political Campaigns

Last registered on December 22, 2017


Trial Information

General Information

Persuasion and Gender: Experimental Evidence from Three Political Campaigns
Initial registration date
December 21, 2017

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
December 22, 2017, 11:50 AM EST

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


Primary Investigator

Bocconi University

Other Primary Investigator(s)

PI Affiliation
Bocconi University
PI Affiliation
Bocconi University

Additional Trial Information

On going
Start date
End date
Secondary IDs
This study complements with an online experiment the results from "Persuasion and Gender: Experimental Evidence from Two Political Campaigns", IZA Discussion Paper No. 9906, by two of the PIs (Tommaso Nannicini and Vincenzo Galasso). The existing working paper investigates the differential response of male and female voters to competitive persuasion in political campaigns with a survey experiment during the electoral race for mayor in Milan (2011), and a field experiment during the electoral race for mayor in Cava de’ Tirreni (2015). In both cases, a sample of eligible voters was randomly divided into three groups. Two were exposed to either a positive or a negative campaign by one of the opponents. The third—control—group received no electoral information. In Milan, the campaigns were administered online and consisted of a bundle of advertising tools (videos, texts, slogans). In Cava de’ Tirreni, we implemented a large scale door-to-door campaign in collaboration with one of the candidates, randomizing positive vs. negative messages. In both experiments, stark gender differences emerge. Females vote more for the opponent and less for the incumbent when they are exposed to the opponent’s positive campaign. Exactly the opposite occurs for males. These gender differences cannot be accounted for by gender identification with the candidate, ideology, or other observable attributes of the voters. The proposed study aims at uncovering the underlying mechanism behind this puzzling result with the use of an online experiment. In particular, we plan to expose participants to a fictitious mayoral race to either a positve or negative campaign video message by one of the opponents and to measure with state-of-the-art elicitation methods from experimental economics the participants' degree of risk aversion, competitiveness, overconfidence and cooperation. The goal is to replicate the differential response to positive vs. negative messages between men and women and to investigate whether this heterogeneous treatment effect can be accounted for by gender differences in individual behavioral traits.
External Link(s)

Registration Citation

, , Tommaso Nannicini and Salvatore Nunnari. 2017. "Persuasion and Gender: Experimental Evidence from Three Political Campaigns." AEA RCT Registry. December 22.
Former Citation
, , Tommaso Nannicini and Salvatore Nunnari. 2017. "Persuasion and Gender: Experimental Evidence from Three Political Campaigns." AEA RCT Registry. December 22.
Experimental Details


We manipulate (between subjects) whether participants to an online survey who are asked to express their intention to vote between two candidates in a fictitious mayoral election are exposed to a "negative" video message (that is, a video message centered on the opponent's flaws) or to a "positive" video message (that is, a video message centered on one's own virtues) by the challenger (keeping the incumbent's video message constant).
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Vote intention in fictitious election; perceived ideology of challenger; perceived valence of challenger; respondent's risk aversion; respondent's competetiveness; respondent's overconfidence; respondent's propensity to cooperate (in game of voluntary public good provision).
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Regardless of the treatment he/she is assigned to, each participant will be asked to fill in an online questionnaire which encompasses three sections. In Section 1, participants will be presented with a vignette presenting a fictitious mayoral race in a small Italian town they have just moved to; participants will watch a 60s video (recorded with professional actors) from each of the two main candidates and will then be asked to express their intention to vote for either candidate. They will also be asked to express what candidate they perceive to be most confidence of his electoral success and, focusing on the candidate whose video message is our experimental manipulation, they will be asked how they perceive this candidate's ideological leaning and overall ability to be in office. In Section 2, participants will be asked three standard non-incentivized/self-reported questions on their ideological position, their propensity to trust others, and their propensity to cooperate with others. At this point in the survey, we will insert a screener question to evaluate a participant's attention to the instruction (a translation to the Italian setting of a question from Berinksi, Margolis, Sances 2014). Finally, in Section 3, we will measure 4 behavioral traits which we believe can account for heterogeneous treatment effects with standard methodologies from experimental economics that incentivize responses with monetary rewards. First, we will measure participants' competitiveness (that is, the propensity to self-select into a tournament) and overconfidence (that is, the accuracy of a self-assessment of own's own relative performance in a tournament) using tasks commonly employed the literature on gender and competitiveness (for example, Niederle and Vesterlund, 2007 or Buser, Niederle and Oosterbeek, 2014; the main difference with these studies is that we ask participants to find how many times a certain letter appears in a string of 50 random letters rather than asking them to find the sum of 3 or 4 random numbers of 2 digits). Second, we measure participants' degree of risk aversion asking them to choose 1 among 6 lotteries, a task introduced by Eckel and Grossman (2008). Finally, we measure participants' propensity to cooperate, using a standard game of voluntary provision of a public good. The average duration of the survey will be around 20 minutes and the average compensation will be around €4 (€2.5 of participation fee and €1.5 based on performance in the games described above).
Experimental Design Details
Randomization Method
Randomization done by a computer. We independently randomize whether each individual is exposed to a negative or positive message by the challenger and the order in which the two video messages (one by the incumbent and one by the challenger) are shown.
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
We will recruit 1,000 individuals to participate to the survey. Since we intend to study gender differences in average treatment effects, we randomize the treatment at the gender level (that is, we have 2 clusters).
Sample size: planned number of observations
1,000 individuals
Sample size (or number of clusters) by treatment arms
500 participants (250 women and 250 men) will be exposed to a negative campaign message by the challenger (and a positive campaign message by the incumbent); 500 participants (250 women and 250 men) will be exposed to a positive campaign message by the challenger (and a positive campaign message by the incumbent).
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)

Institutional Review Boards (IRBs)

IRB Name
Bocconi Research Ethics Committee
IRB Approval Date
IRB Approval Number


Post Trial Information

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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