Her work, including the new “Infinite Life,” involves silences full of meaning. But what exactly they convey can change depending on the director.“The Flick,” a play by Annie Baker, had its premiere at Playwrights Horizons in 2013. Its three hour and 15 minute runtime included long stretches in which the characters — three underpaid workers in a tired, single-screen movie theater — moved from row to row, sweeping the floor. The drama found a kind of poetry in everyday speech: the hesitations, filler words, abandoned sentences and otherwise awkward attempts to connect. A lot of the time, Baker’s characters didn’t speak at all.The show apparently tested the patience of some. “We’d see a lot of empty seats after intermission,” the actor Matt Maher said. A widely shared email from the Playwrights Horizons artistic director at the time, Tim Sanford, made reference to emphatic expressions of displeasure from subscribers and much hand-wringing behind the scenes. He wrote that “we had lengthy discussions about what to do.”In a recent conversation in a cafe in Chelsea, Baker, who won a Pulitzer Prize for “The Flick,” said she was untroubled by the walkouts. “I don’t think of myself as a provocateur, but I also don’t think of myself as an entertainer,” she said. “People walk out of my plays all the time. I don’t get freaked out by it.”Louisa Krause and Aaron Clifton Moten in “The Flick” at the Barrow Street Theater in 2015. When Playwrights Horizons staged it, the show tested the patience of some audience members.Sara Krulwich/The New York TimesBaker’s best known works are partly symphonies of silence in which what might be mistaken for dead air is anything but. Her scripts call for comfortable pauses, uncomfortable pauses, weird pauses, confused pauses, horrible pauses and, in “The Flick,” a happy pause that morphs into an awkward pause. When we’re not watching unspeaking characters sweep up popcorn, we might be watching them mutely smoke, drink tea or hula-hoop. Her script for “The Aliens” begins with a taxonomy: “At least a third — if not half — of this play is silence. Pauses should be at least three seconds long. Silences should last from five to 10 seconds. Long pauses and long silences should, of course, be even longer.”“She’s a high priestess of silence and stillness,” the director James Macdonald said.An Atlantic Theater Company and National Theater co-production of Baker’s latest play, “Infinite Life,” directed by Macdonald, is in previews now and will open on Sept. 12. It is a play about the experience of pain — our own and each other’s. “Infinite Life” also goes further than Baker’s other plays in its exploration of stillness, Macdonald said. “Nothing appears to be going on for great stretches.”Then, in October, “Janet Planet,” Baker’s debut feature film as writer-director, will screen at the New York Film Festival, before a wider release next year. Baker said the film used a natural soundscape but no musical score, and replicated the way time felt to her 11-year-old self.While she has said that some of her “favorite moments in all of my plays are usually moments when people aren’t talking,” Baker also insisted that she was not obsessed with quietude.“I’m interested in silence, I’m interested in noise, I’m interested in speed, I’m interested in stillness. To me it does feel like writing a play feels a bit like composing a piece of music. There are the quarter notes and there are the rests.”From left, Nielsen, Pressley, Burke and Katigbak in “Infinite Life.” Katigbak explained that the silence isn’t empty: “There has to be something happening. Even when it’s at rest, it’s active.”Jeenah Moon for The New York TimesOn the air and space that pervades her work, she added, “It was never a conscious decision or aesthetic cultivation on my part. It’s just me trying to follow my own pleasure and my own taste and my own ear.”Ten years after the “Flick” fracas and ahead of the opening of “Infinite Life” — with productions of Baker’s earlier plays still finding audiences around the world — it’s worth contemplating what’s going on between the lines in her low and slow theater. For starters, why do some audience members find silence so off-putting?Amy Muse, a professor of English at the University of St. Thomas in St. Paul, Minn., and the author of “The Drama and Theatre of Annie Baker,” offered a theory rooted in the metaphysical. “We fear silence because it seems to indicate an absence of meaning,” she wrote in an email, adding, “Indefinite stretches of time, like space, fill people with dread.”More likely, she continued, “they’re fearing they’ve wasted time and money to be bored watching ordinary people doing ordinary things, instead of listening to the smart dialogue they expect from a play.”For admirers, though, Baker extends “a kind of sacred invitation to be present,” Muse said. It urges a leaning in, sensitizing us to the minutest moments, gestures and expressions, and the ever-present ache of her characters. What’s said attains extra significance surrounded by what’s unsaid, and details accumulate like snowfall, as the critic Hilton Als wrote in The New Yorker.It was in the quietest moments in “The Flick,” Maher said, when he could feel the audience most tuned in. “Like I could just shrug or raise an eyebrow and could feel the audience clocking it.”Baker’s preference for understatement stands out, not just when compared to most mainstream entertainment, but also much of daily life. “To me it’s very countercultural,” said the “Infinite Life” actor Christina Kirk. “In the sense that our dominant values are bigger, faster, louder, more. I think that generally Annie is interested in exploring smaller, slower, quieter, less.”Kirk said she found Baker’s silences countercultural because “our dominant values are bigger, faster, louder, more.”Jeenah Moon for The New York TimesIn a way, the audience members who gave up on “The Flick” were fooled by a fundamental deception on Baker’s part. Not much seems to be happening, and yet everything is happening. Darker truths emerge, awful revelations occur, human cruelty, despair, shame and weakness come into shocking focus. As Chekhov — a key influence for Baker — wrote: “People are sitting at a table having dinner, that’s all, but at the same time their happiness is being created, or their lives are being torn apart.”There’s a specificity and precision required of actors and directors. “The biggest lesson as a director was that those pauses and silences need to be active — as taut and as fully inhabited as the most exhilarating monologue,” said Mitchell Cushman, who has directed productions of “The Flick” and “The Aliens” in Toronto. “I distinctly remember the work we did on ‘The Flick’, after first preview, to pick up the pacing in the long silences.” The silences didn’t get any shorter. Rather, “they got much more charged. It made all the difference.”Macdonald provided the cast of “Infinite Life” with a mantra: “Still bodies, alert minds.”“Those moments of stillness can’t be empty,” the actor Mia Katigbak explained. “There has to be something happening. Even when it’s at rest, it’s active.”Not every production has adhered religiously to Baker’s stipulations. One London staging of “The Aliens” shaved its runtime from at least 100 minutes, with an intermission, to 75 minutes without. Perhaps even more egregious, Baker witnessed regional theater performances in which the pauses were halfhearted. “I could tell they were counting to five during them,” she said. “Now I just don’t see productions in my plays that I wasn’t involved with.”On the other hand, for productions of “The Aliens” and “Circle Mirror Transformation” in Moscow, the director Adrian Giurgea felt it more in keeping with Stanislavskian psychological realism to extend the stretches of non-dialogue to “unbearable” lengths — up to 11 minutes long, he said.“Circle Mirror Transformation” at Playwrights Horizons. A production in Moscow extended the silences to as long as 11 minutes.Sara Krulwich/The New York TimesSome silences can feel more vibrantly alive than others, or suggest a porosity between the real world and the world of the play. Maizy Scarpa directed an outdoor production of “The Aliens” in the Berkshires, in a tunnel under active railroad tracks. “I had to remind the actors to acknowledge ambient sounds, not fight with them,” she said. “If someone shouts in the distance, look up! If there is a car that honks during your monologue, react!” Ultimately the audience “could absorb the whole experience.”In a production of “The Aliens” at the Old Fitz, an 80-seat theater in a Sydney pub that allows patrons to bring in their drinks, the silences were relatively raucous, particularly on trivia night. “The audience really felt like they were in the yard, hanging out with the characters, having a beer,” the director Craig Baldwin said. “If you think about an audience as always being a silent participant in a piece of theater, it was particularly magic when the characters joined them in that silence. Everyone in the backyard was silent together.”Which suggests another way to think about these moments: as audience participation. It’s an opportunity — whether we accept it or reject it — to fill those silences with ourselves.“Ideas are often the most powerful when they’re hidden,” Baker said. “It’s so delicious to feel a character having a thought and not know, not have access to what that thought is. I like to allow an audience member to make the discovery themselves.” More