‘Eighth Grade’ is a middle school marvel

Elsie Fisher in Bo Burnham’s “Eighth Grade.”A24

Of all the terrible ideas in the history of civilization, middle school has to rank as one of the worst. Take a cohort of children who’ve known each other since kindergarten and, just as their hormones start popping and they’re agonizing over identity and appearance and acceptance, throw them into a bigger pool of equally insecure kids. For added cruelty, sprinkle in a few social media platforms designed to highlight the most superficial aspects of adolescent life. They should give out Purple Hearts just for making it to high school.

As portrayed with supreme awkwardness and not a shred of vanity by the young actress Elsie Fisher in “Eighth Grade,” Kayla Day is just about ready for her medal. To her 13-year-old peers, she’s a nonentity, the girl who sits in the back of the room and doesn’t say anything. At home, she makes and uploads teen-advice videos that no one ever watches and speed-scrolls through her phone’s social media feed, nose pressed up against the glamorous lives of others.

She takes selfie after selfie after selfie, hoping to find the one Kayla who’s grown-up and perfect. She is unspeakably mean to her father, a well-intentioned single schlub, played with an empathetic cringe by Josh Hamilton.

Kayla is, in short, an American girl in the early decades of the 21st century, and writer-director Bo Burnham has captured her existence — hopes and fantasies and daily mortifications — with a precision that makes your heart die and get reborn with every scene. At times, “Eighth Grade” plays like a nature documentary about life and death on the savannas of suburbia.

One of the sharpest arrows strikes early. As the eighth graders get ready for their upcoming graduation, they’re given back the “time capsules” they made three years earlier, and as Kayla opens the shoebox with “To the Coolest Girl in the World” written on the lid, your heart sinks with hers. Nothing changed. Everything got worse.

Burnham, a Hamilton native, found fame early in his career as a singer-comedian online and elsewhere, but in his feature filmmaking debut, he directs with sympathy and remarkable assurance. “Eighth Grade” is low-budget rough on the surface but each shot has weight and wit as it measures the yawning chasm between Kayla and her peers. The film’s mordantly funny, too, and blunt about the vapidity of the classmates the heroine looks up to, the girls dead-eyed gazelles staring at their phones, the boys pre-pubescent hook-up wannabes.

The attention she gets from a proudly nerdy kid named Gabe (Jake Ryan) is one of Burnham’s rare concessions to formula, as is some of the heart-to-heart dialogue in the scenes with dad. Elsewhere, “Eighth Grade” feels freshly and caustically seen, from Kayla’s fumbling attempts to convince her crush (Luke Prael), a preening lout of a boy-man, that she’s sexually worldly, to a pool party that feels like a middle-school version of the Actor’s Nightmare.

Just as she and we are starting to despair, hope arrives in the form of Olivia (a winning Emily Robinson), the high school senior Kayla is assigned to shadow for one day. Not only is Olivia sunny, thoughtful, and confident, she offers real friendship to the younger girl and, crucially, proof that there’s life and humanity in the undiscovered country on the horizon.

But there’s darkness there, too, and “Eighth Grade” is at its nerviest and most nerve-wracking in a sequence between Kayla and one of Olivia’s friends (Daniel Zolghadri) that highlights the vulnerability of young girls skating along the edge of adulthood, hoping to be liked. Burnham knows that often the hardest and most courageous part of adolescence is figuring out who you don’t want to be.

In addition — and without losing its head — “Eighth Grade” paints social media and the addictive crutch of mobile phones as just one more set of unrealistic expectations for a young girl to contend with, and perhaps a critically ruinous one. And as Burnham’s filmmaking is unfussy yet thought through, so Fisher’s seemingly artless performance is actually a pretty brilliant piece of acting.

She nails the stammers and the gawkiness, the body misery, the way an impressionable kid can try to say what she thinks others want to hear before backing out of a sentence halfway through. But Fisher lets us see Kayla’s innate kindness and quick thinking as well, even if the girl doesn’t have all the words to express herself yet, and she doesn’t sugarcoat the rudeness toward Hamilton’s hapless dad.

The star was 14 when “Eighth Grade“ was filmed, but she’s been acting since she was 6; she voices the youngest of the three girls in the “Despicable Me” movies, among other roles. So Fisher’s a pro — and enough of one to convince you she’s just walked out of the mall and back into her bedroom, chewing her nails, her heart, and her hopes to the quick.

★ ★ ★ ½
EIGHTH GRADE

Written and directed by Bo Burnham. Starring Elsie Fisher, Josh Hamilton, Emily Robinson. At Boston Common, Kendall Square. 94 minutes. R (language, some sexual material, none of which would cause your average eighth grader to bat an eye)