Jeff, Who Lives at Home

The Jeff who lives at home in “Jeff, Who Lives at Home” is a 30-year-old pothead who rarely leaves the coziness of his mother’s basement, where he has all the weed, snacks, and TV he needs. He’s played by Jason Segel, which probably tells you a lot, and the film was written and directed by brothers Mark and Jay Duplass (“The Puffy Chair,” “Cyrus”), which should tell you a little more.

What might catch you by surprise is how warm and endearing this affable comedy is, and how soul-stirring Jeff’s silly revelations turn out to be. Running a simple errand for his mother while under the influence of metaphysical thinking (and, yes, marijuana) leads Jeff on a quest for self-actualization that involves his mom, brother, sister-in-law, and others, resulting in a pleasingly sunny resolution that will give you a serious case of the warm ‘n’ fuzzies.

Obviously, M. Night Shyamalan’s “Signs” plays a significant part. Wait, maybe that isn’t obvious. Jeff is a big fan of that film, you see, finding particular import in its everything-happens-for-a-reason philosophical underpinnings. When Jeff’s phone rings and the caller asks for Kevin, Jeff doesn’t think of it as a wrong number. He thinks of it as a sign. When he is subsequently given a task by his mother, Sharon (Susan Sarandon), who fusses over him while working an office job, Jeff is determined not just to do what has been asked of him but to discover how this “Kevin” person factors into things.

His adventures in town (the film is set in Baton Rouge) involve several coincidences not unlike those found in “Signs.” He happens to run into his older brother, Pat (Ed Helms), a goateed doofus who’s oblivious to how his buying a new Porsche might upset his wife, Linda (Judy Greer), who might be cheating on him. Jeff and Pat end up antagonizing and assisting one another in their respective missions (run that errand for Mom; figure out whether Linda is having an affair), while back at the office Sharon gets instant messages from a “secret admirer.” Every character’s day-to-day existence is in need of being shaken up, and this is the day it’s going to happen.

The family dynamics between Jeff, Pat, and their mother are recognizable and funny, sometimes painfully so. I might be nearing the limits of my appreciation for Ed Helms’ dweeby cornball characters, but he’s mastered the art of it, just as Segel has replaced Seth Rogen as our favorite baby-faced slacker. Segel and Helms operate like a comfortable old comedy team. Meanwhile, Susan Sarandon — no stranger to comedy but rarely fully appreciated for it — brings sincerity to her role as the boys’ tender-hearted mother.

Now that the “Mumblecore” movement in indie filmmaking has lost what hipster-powered momentum it had, it’s clear that the only survivors are the Duplasses. The reason for this is that they have evolved. “Cyrus” had better production values and bigger names than “The Puffy Chair” and “Baghead,” but it retained the witty, affectionate tone of the brothers’ previous work while stretching the “immature man-boy has to grow up” premise just a little. “Jeff, Who Lives at Home” likewise does something fresh with its familiar-sounding scenario. Where many of their colleagues are content to make the same movie over and over again (why yes, Joe Swanberg, I am thinking of you), the Duplasses build on what they’ve done before by finding new ways of making their protagonists learn things about themselves. Maybe they can’t keep riffing on that theme forever, but they’ve got a winning formula for now.

B+ (1 hr., 26 min.; R, a lot of harsh profanity, some vulgarity.)