Does the voice of a particular politician rub you the wrong way? At this point in the (seemingly endless) 2016 election season, it’s hard to blame anyone who can’t stand to hear another word from presidential hopefuls. But if linguist and psychologist Rosario Signorello has his way, you won’t turn off your speakers just yet. Signorello specializes not in what politicians say, but how they say it — and his research reveals some surprising truths about how candidates speak.

At a recent meeting of the Acoustical Society of America, Signorello, who is conducting postdoctoral research in the Department of Head and Neck Surgery at the UCLA’s David Geffen School of Medicine, presented his most recent research on the voice acoustics of four presidential hopefuls: Donald Trump, Hillary Clinton, Bernie Sanders and Carly Fiorina, who ended her presidential bid in February.

Signorello is interested in what he calls the “charismatic voice” — the vocal stylings that politicians use to project leadership characteristics like emotion, vision and dominance. “It’s a very complex cognitive phenomenon,” he says, and it combines physiology and psychology. Like anyone else, presidential candidates use their body to produce sounds, which are then heard and interpreted by their audience. Although their messages vary widely, the ways in which politicians deliver them with their voices are surprisingly similar.

How similar? Signorello and a research team analyzed three speech samples from each politician to find out. First, they focused on speeches delivered during political rallies to diverse audiences in a large venue. They extracted every vowel of the speeches and calculated the loudness and vocal pitch of each speaker. Even though each politician has a distinctive voice, they shared a charismatic strategy during speeches to diverse audiences — they spoke using diverse pitches and intensities.

“They have a very wide vocal profile,” Signorello says. “In this case, the leader is already recognized and has a leadership status that is higher [than his audience]. Their followers are very diverse. Given that the audience is very diverse, there are a lot of different expectations.” Different expectations led to differing tones and intensities across a relatively broad spectrum — a strategy shared by every candidate.

The candidates shared strategies when they spoke to an audience of fellow leaders, too. During speeches at the United Nations, the New Hampshire Republican Leadership Summit and on the floor of the U.S. Senate, the politicians changed things up. Rather than speak with a wide vocal range, every politician kept their voices within a relatively narrow range when addressing other leaders.

That’s a typical power play, Signorello says. “When you address someone of your same social status, you try to prevail,” he says. “You want to convey few images of yourself that are more related to dominance.” By keeping to lower pitches and less diversified tones, Signorello says, leaders speaking to other leaders take a page from the book of other dominant animals, who portray their size and fearsomeness with low-pitched grunts.

Finally, Signorello and his team studied the voices of politicians in conversational settings (talk shows) while speaking about non-political subjects. The vocal ranges were even more narrow in those contexts, reflecting the normal speech patterns of a healthy voice.

Signorello compares politicians’ ability to modulate their voices with the way other people dress up or use makeup before appearing in public. “Politicians are very good at using different patterns for different communication platforms,” he says. “They are confronted with every type of communication context with every type of different audience.”

Surprisingly, both genders used their voices to project dominance in the same way — a finding that counters claims that female politicians are shrill or grating. “Dominance is not only found in the male gender,” Signorello says. “We know now that the voice range of politicians is something that is cross-gender.” Trump stretches his voice as much as Hillary Clinton when addressing a diverse audience, he adds. “There is no male or female.” Accusations that Clinton speaks like a man are off base, he says: “If they were fair, they [would] say that Donald Trump speaks like a woman because he uses a very high-pitched voice, too.”

These vocal stylings appear to cross cultural boundaries as well. Signorello, who has studied the voices of politicians from around the world, suspects that politicians’ use of the voice is part evolution, part culture. Next, he plans to see how those patterns are reflected (or negated) within the animal world, too. Since culture moves quickly, he warns, vocal patterns that work in one election season (like low pitches that express authoritarianism) may not work in another. “Today an authoritarian charisma works, but probably in four years it will not work anymore.”

So is there a sure-fire way for politicians to project charisma with their voices? Not exactly: Rather, politicians can exemplify charisma differently for different groups and contexts. And content is just as important as delivery, Signorello says. “My theory is that charisma can be divided into two types — charisma of the mind and charisma of the body.” Not every leader is endowed by both, but every word — and tone — helps.

Erin Blakemore (@heroinebook) is a freelance journalist from Boulder, Colo. She is the author of "The Heroine’s Bookshelf" (Harper). 

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