Donald Trump (second from right) speaks as Jeb Bush (left) Marco Rubio (second from left) and Ben Carson (right) look on during the CNBC Republican presidential debate at the University of Colorado in Boulder, Colorado, Oct. 28, 2015.
According to new research, politicians have similar ways of speaking, even when they are saying very different things.

Scientists recently analyzed the speaking style of Hillary Clinton, Carly Fiorina, Bernie Sanders and Donald Trump. They found that all four presidential contenders in the 2016 race altered their voices in similar ways, depending on the audience.

The research was described at the Acoustical Society of America meeting in Salt Lake City, Utah. The findings offer some new insight into the vocal strategies of political speakers.

The Voice Of Power Or The Power Of Voice

"Politicians use voice as a very powerful behavior to convey their charisma," Rosario Signorello said at a briefing this week. Signorello, one of the researchers behind the study, works at UCLA's Department of Head and Neck Surgery.

When it comes to politics, it's not what you say, it's how you say it. There's a good reason that some of the most successful politicians, for better or worse, are also known as great speakers. The most skilled political speakers possess the ability to persuade large crowds of very different people.

The key to their success does not lie solely in the words they choose but also in the way they speak. The same paragraph might sound boring in a dull speaker's voice but dramatic when recited by a Shakespearean actor. Experienced politicians know that speaking style and delivery are extremely important.

Politicians, Signorello said, "are the best public speakers because they face every type of audience, from elementary school to very old people."

Speaking Of Strategies

Signorello wanted to see whether there was a way to pin down what makes a politician an effective speaker by analyzing the strategies they use. He chose two Democrats, Clinton and Sanders, and two Republicans, Trump and Fiorina, and analyzed the frequency, or pitch, of the voices of all four subjects.

He and his colleagues studied the speech of the candidates in three different settings. They looked at political rallies, discussions with other political figures, and talk show interviews that were not about politics. The scientists analyzed three different speeches for each candidate in each setting. They found that the four politicians shared some similar vocal behaviors despite their differences in party or gender.

When speaking to large crowds of people, all of the politicians used a wide range of pitch, speaking in a high pitch at times and in a low pitch at other times. Signorello and his fellow researchers have found that this strategy helps speakers to be seen as charismatic and likable.

The Highs And Lows

Candidates used a high vocal pitch range when speaking to general audiences of voters, rather than to other politicians and leaders. On average, candidates used a high pitch, and they mixed loud and soft volumes with these audiences.

This strategy makes sense, Signorello said, for audiences made up of a wide variety of people who differ from each other greatly. Candidates must adjust their speech to appeal to the many different groups at the same time. Candidates try to meet each group's expectation of what a charismatic leader should sound like, he said.

In contrast, when the politicians were addressing other politicians, they limited their pitch to the low and medium frequencies. The researchers observed this when Clinton spoke to a United Nations commission and when Sanders spoke to the United States Senate. The same was true when Trump and Fiorina spoke at the New Hampshire Republican Leadership Summit. That's a pattern that's meant to signal power and dominance. A politician may lower their pitch range in these situations to show that they are comfortable among other powerful people, Signorello said.

When candidates address leaders, the audience members are usually all very similar, as most of them are men of a certain age, Signorello said. The candidates, then, do not have to change their speaking style as much when they talk to each other, because they are not talking to many different kinds of people at the same time.

Leveling Off

However, all of the politicians used their normal pitch ranges when chatting about nonpolitical subjects on talk shows. None of the candidates stretched their frequencies or loudness in this situation, according to Signorello.

It sounds as if politicians have tapped into some vocal strategies for impressing an audience, but that doesn't mean that they all behave exactly the same. The researchers discovered that the different candidates all have their own particular quirks.

For example, Clinton and Fiorina tended to lower their vocal pitch when addressing large crowds. Trump appeared to do the exact opposite, and Sanders had an especially wide pitch range over the course of a speech.

Sanders usually speaks to audiences made up of people of a wide variety of ages, cultural backgrounds and genders, Signorello said. He has to adjust his speech often because he wants to be liked by everyone.

Next, the scientists also want to see whether politicians in other countries share similar behavioral patterns to those in the United States, Signorello said.

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