Persuasion and gender: Experimental evidence from two political campaigns

Vincenzo Galasso, Tommaso Nannicini

06 June 2016



It is ever more likely that on Tuesday 8 November 2016 we will witness the first mixed-gender US Presidential election. Quite surprisingly, Donald Trump is emerging as the winner from the Republican primaries. From the Democratic primaries, as largely predicted, Hilary Clinton is coming forward as the Democratic nominee – although perhaps with less enthusiasm than expected.

This electoral race has all the components to become one of the most divisive elections in US history. Donald Trump has used an uncompromising style to mobilise voters, taking issue with just about anyone, including the Pope. Support from the establishment of the Republican Party has proved to be rather weak, and he has chosen a political strategy aimed at addressing his voters directly. Hilary Clinton, instead, had already secured massive support from the establishment of the Democratic Party, but her direct appeal to the voters has been far from than terrific. These two different styles of political persuasion will clash during the electoral campaign. And the mixed gender component may add more salt to it.

What type of electoral campaign should we expect? What kind of political show will the two candidates put on to ‘persuade’ the voters? One of the most debated aspects of the campaign is its tone. In fact, during the last decades, the tone of political campaigns for the US Presidential election has become increasingly more negative, and the amount of resources allocated to financing negative advertisements has been massive. This year’s primary elections have represented no exception, particularly as far as Donald Trump is concerned.

But why are spin doctors so keen on going negative? Does negative campaigning contribute to getting out the vote of the loyal electors? Or does it swing votes away from the opponent?

The existing empirical literature on this issue is not conclusive. In their seminal paper on negative campaigning, Ansolabehere et al. (1994) exposed a sample of 1,655 eligible voters in three electoral races in California to a single (positive vs. negative) political ad, aired during a commercial break. Using responses from a post-test questionnaire, they found that the negative ad actually reduced average voting intentions by 5%. Arceneaux and Nickerson (2010) implemented a field experiment in which volunteers personally delivered a political message to their treatment groups. They found that, while canvassing is effective in influencing voters, there is little evidence of a differential effect between negative and positive campaigning.

In a recent paper, we readdress this issue from a different angle (Galasso and Nannicini 2016). We argue that the personal traits of the receivers may be important in determining how effective persuasion can be, particularly – but not only – in political campaigns. And a natural candidate among these personal traits that may determine the impact of different electoral messages is clearly the gender of the receiver. After all, advertisers have long used different arguments to persuade female and male buyers.

To tackle this question, we study gender differences in the response to competitive persuasion in two political campaigns. We implemented a survey experiment in the field and a large-scale field experiment during two different electoral campaigns in Italy, and analysed the effect of positive versus negative electoral campaigning on turnout and voting behaviour of male and female voters.

Our first experiment was implemented in Milan during the 2011 election, which featured a female incumbent facing a male main opponent. We provided four surveys to an online sample of about 1,500 eligible voters. Respondents to the initial profiling survey were randomly assigned to two treatment groups—positive vs. negative campaigns by the main opponent—and to a control group that were exposed to no campaign information. Participants in the positive (negative) group were exposed to electoral campaign messages with a positive (negative) tone by the main opponent. All participants in both treatment groups were also exposed to the actual (non-randomised) campaign by the incumbent. Unlike existing studies on positive versus negative campaigning, we administered a ‘complete’ electoral campaign, with a positive or negative tone, composed of several devices of political persuasion: a video interview with the candidate, an electoral slogan, an open letter to the voters, and a video ad endorsed by the candidate. The positive and negative ads both addressed the same issue, with the same format, and in the same setting. To administer these four tools, we used two surveys. The ‘in the field’ component of our experimental design comes from collecting turnout and voting choices through a final survey, run in the days immediately after the election. The empirical results from this first experiment unveil large differences by gender in the response to political persuasion strategies. Negative advertising increases  turnout by men by about 8 percentage points, but has no effect on women. Gender differences are even stronger for electoral choices. Females vote more for the opponent (by 8 points) and less for the incumbent (by 8 points) if exposed to the opponent’s positive campaign. Exactly the opposite happens for males, who vote less for the opponent (by 11 points) and more for the incumbent (by 12.7 points) if exposed to the opponent’s positive campaign.

Is this gender difference in the response to competitive persuasion driven by gender identity (Akerlof and Kranton 2000)? After all, the 2011 election in Milan featured a mixed gender race. Female voters may have ‘identified’with the female incumbent and thereby disliked the male opponent’s negative campaign. To assess the gender identity motive, we exploit a natural experiment. During a campaign debate on Sky TV, the female incumbent violently attacked the male opponent by accusing him of strong ties with communist terrorists in his youth. Since this debate was aired during our third survey, we compared the responses of individuals who happened to answer the survey just before or just after the show, to find again that males and females have opposite reactions. Males lean more toward the (female) sender of the negative attack, and females align with the (male) candidate targeted by the attack. We also collected Twitter data and performed a sentiment analysis on the tweets sent by male and female users 24 hours before and 24 hours after the Sky TV debate. After the Sky TV debate, more negative tweets were sent by males regarding the male opponent and by females regarding the female incumbent. Both the survey and Twitter evidence suggest that gender identification is not a first-order mechanism.

Our second randomised controlled trial is a large-scale field experiment, which took place during the 2015 electoral race for mayor in a mid-sized Italian city (Cava de’ Tirreni). The experiment was designed to examine the differential gender effects of negative (and positive) electoral campaigning by a male opponent against the male incumbent. This field experiment featured a randomisation into positive or negative treatment and control group at the electoral precinct level. The treatments consisted of positive and negative canvassing, done by a campaign team of 20 young supporters of one of the opponents, who tried to engage in personal interaction with eligible voters by knocking on doors and also distributed electoral material. The electoral material consisted of a flyer and a hanger with either a positive or a negative message, but with the same format and addressing the same issues. Canvassing took place in the three weeks before the election. Volunteers used a script with a positive or a negative message, and covered the entire voting population—personally or by leaving electoral materials in the mailbox—in all the 36 (out of 55) treated precincts. We then conducted a post-electoral survey for a sample of the eligible (treated and untreated) voters to obtain (self-reported) information on turnout and actual votes. The empirical results from the field experiment in Cava de’ Tirreni persuasively confirm our previous findings – the difference in the response to political persuasion strategies by gender is statistically significant and politically relevant. Among male voters, negative campaigning by the male opponent against the male incumbent increases his votes by 15.4 percentage points, while reducing the votes for the incumbent (by 27 points). Among females, positive campaigning by the opponent increases his vote shares by 12.8 points, while reducing votes for the incumbent (by 18 points).


We use different methodologies — surveys, a natural experiment, and a field experiment—in different geographic environments (Milan, the largest city in the North of Italy, and Cava de’ Tirreni, a mid-sized city in the South), with different gender races—mixed in Milan and all male in Cava de’ Tirreni—and exploit several electoral campaign instruments (video ad, slogan, flyer, and canvassing). All this experimental evidence points in the same direction - the gender of the receiver matters. Among female voters, positive campaigning by the opponent increases his vote share and reduces votes for the incumbent, while the opposite occurs among male voters.


Akerlof, G.A., and R.E. Kranton (2000), “Economics and Identity,” Quarterly Journal of Economics, 115(3): 715–753.

Ansolabehere, S., S. Iyengar, A. Simon, and N. Valentino (1994), “Does Attack Advertising Demobilize the Electorate?” American Political Science Review, 88(4): 829–838.

Aceneaux, K., and D.W. Nickerson (2010), “Comparing Negative and Positive Campaign Messages,” American Politics Research, 38(1): 54–83.

Galasso, V. and T. Nannicini (2016) “Persuasion and Gender: Experimental Evidence from Two Political Campaigns”  CEPR Discussion Papers No 11238



Topics:  Gender Politics and economics

Tags:  US presidential election, gender, campaign strategies, voting behaviour

Professor of Economics, Bocconi University; CEPR Research Fellow

Professor of Economics, Bocconi University