Christopher Hart, a professor of linguistics at Lancaster University in the U.K., noticed something early on about how U.S. President Donald Trump communicates: The man loves to point, and it has a surprisingly powerful effect on his followers. (More on that later.)

Unlike a lot of politicians, Trump ― always a bit of a showman, given his reality TV background ― connects with his supporters at political rallies with a combination of rhetoric and gestures. It’s not just during speeches that he’ll strategically point his fingers; he’ll point to a political ally after they introduce him on the campaign trail, or to a member of the administration he wants to boost, like he did here at the White House in 2018 with outgoing spokesperson Hope Hicks.

He homes in on his enemies by pointing, too, like he did in the final presidential debate against Hillary Clinton in 2016, pictured below. It’s a kind of “can you believe this person?” index-finger indictment.

He’s given to pointing to himself, too ― or to the branding on a Trump hat.

And if there’s a solar eclipse, he’ll definitely point and stare at that bad boy, even if scientists warn against doing so without protective eyewear.

Hart, the aforementioned researcher, is intrigued by Trump’s penchant for pointing because, while a decent amount of research has been devoted to how politicians use their words to influence followers, few have studied the ways nonverbal cues can cultivate a following.

“I am interested in the gestural performances of right-wing populists specifically, so Trump was an obvious place to start,” Hart told HuffPost.

In a recent study published in the journal Social Semiotics, Hart analyzed a campaign rally and found that Trump defaults to a pointing gesture more than once per minute, which is a lot.

“Trump is not the only politician to make use of pointing gestures, but I was surprised at just how frequently he points,” he said. “There is something about the live setting of the campaign rally that seems to invite a density of pointing gestures for him.”

To carry out his study, Hart looked at a 60-minute video recording of a presidential campaign rally held in Buffalo, New York, on April 18, 2016. The high-energy rally ― viewable on YouTube ― was attended by more than 11,000 people in Trump’s home state.

When Trump points outward, away from his body, he’s either referring to the audience directly (“you”) or to enemy third parties (“they,” “them,” or specific individuals or groups like the media or protesters).

When the president points at his followers, he’s engaging with them, drawing them further into the fold. When he points to his critics ― media in the stands or protesters who’ve gotten into the event ― he’s “othering” them, singling them out as an object of scorn.

Trump’s always pointing, Hart found, even absent of speech: “He does it to great effect, either as a show of appreciation toward individual audience members or as part of theatrical routines, like pointing to the top of an imagined border wall.”

And when he points, his crowds of supporters eat it up, Hart said.

Of course, Trump’s pointing reflects his experience in the entertainment world: Before “The Apprentice” made him a reality TV star, he was a frequent guest on WWE, where wild gesticulating and other theatrics ― head-licking, head-shaving ― are commonplace.

“The way he points and singles out audience members is definitely characteristic of live entertainment,” Hart said. “He’s including himself with the audience, as a man of the people.”

As for Trump’s habit of pointing to himself, Hart figures that’s done to demonstrate sincerity or build a quick emotional rapport with his audience. He similarly points downward when speaking about a location ― “this country” or “Buffalo” ― to connect a broader political message to the specific location of the rally: Don’t worry, you ― or your city ― will directly benefit from this political agenda.

Why does any of this matter? Because something as simple as finger-pointing speaks to how Trump gained his unprecedented populist following.

“The way Trump uses pointing gestures breaks with the ways politicians normally communicate, making for an energized and entertaining performance,” Hart said. “That’s a large part of his appeal.”

Previous studies have shown that politicians traditionally rely on a “restricted gestural code” ― a small, stable set of gestures ― presumably having been told that minimal movement conveys confidence, assertiveness or intellectual precision, Hart said.

“An example of this is the ‘thist,’ in which the thumb is placed horizontally over a clenched fist,” Hart said. “Other gestures are avoided perhaps for fears that they will distract audiences from the main message.”

In the wrong hands, though, that can all feel stiff and overly rehearsed. At worst, it distances the politician from the way the rest of us communicate, Hart said. Think of how stilted Richard Nixon came across when juxtaposed with the cool, calm, collected body language of John F. Kennedy during the 1960 presidential debate. (Kennedy would of course go on to win.)

Stiff body language “is not the case for populist politicians whose gestures seem to be more spontaneous, conversational in style and genuinely charismatic,” Hart said. “They often reflect, albeit in an exaggerated form, the way ordinary people interact. It’s part of the populist playbook.”

Another high-profile populist pointer, according to Hart? Boris Johnson, the former prime minister of the United Kingdom. No word if unruly, über-blond hair is part of the populist playbook, too.