It's striking, then, that few of these films make much mention of studying; it's all binge drinking, sexual fumblings and power plays between mean girls. From the look of it, nobody ever gets a degree.

''It's ironic,'' says Josh Radnor, who wrote and directed the indie hit Liberal Arts, ''because the reason people ostensibly go to college is to learn.'' His film follows the fortunes of a likeably bookish chap of 35, played by Radnor himself, who still hankers for the university cloister.

There isn't even a whiff of the frat house. ''I was really interested in exploring someone whose consciousness was really awakened by college,'' Radnor says, ''and felt that he was really spinning his wheels outside that environment.''

As the movie opens, Jesse Fisher has been stuck for a decade in a job at academia's spiky end; he is a college admissions officer, miserably deciding who should be denied the life he had. When he is asked by one of his old English professors (Richard Jenkins) to make a speech at his retirement dinner, he leaps at the chance to return to the sylvan groves of Kenyon College, Ohio, which is Radnor's own alma mater in real life.

Ostensibly, it is everything he remembers - leafy, stony, the Platonic ideal - so it is no surprise he falls for a muse within its walls. Zibby (Elizabeth Olsen) is the intense 19-year-old daughter of some friends of his professor.

Yes, there is an age gulf, but she reads real books and wants to talk about what they mean, makes him tapes of classical music and insists they correspond by handwritten letters. This is what he has been missing in his life.

Liberal Arts is Radnor's second film as a writer-director - the first was HappyThankyouMorePlease - but he is better-known as the breezy star of the sitcom How I Met Your Mother. He was also 35 when he returned to campus as a distinguished alumnus to show his first film to the undergraduates; it was on that trip, he recalls, that the belated recognition that he was now considerably older than they were struck him as ''a kind of vertigo''. Much of this film was shot at Kenyon. So is he Jesse, then? He looks slightly uneasy.

''I think the nostalgia he was feeling was more me at 26, 27, closer to school,'' he demurs. ''My life has taken me in a lot of different directions and I wouldn't wish away any of that. We obsess over youth so much and I was trying to make a movie about someone who was journeying towards acceptance that where he is now is OK, that every time is going to be great. I really believe those things. And I'm a big reader, but I don't think it's a social problem, whereas Jesse really buries his head in a book and life is going by him without him noticing.

''So I'm lending him a bit of myself but there is also a great distance from me.''

Eventually Jesse has to embrace that he isn't a kid any more. His old professor has already given him a few home truths: even at retirement age, he says, part of him still believes he too is 19.

''That was something my dad said to me years ago,'' Radnor recalls. ''He was just talking about his diet, saying you can't keep eating like you're 19 even though you have the appetite of a 19-year-old, but it stuck with me.'' He smiles. ''The fact that nobody feels like an adult: that is the world's dirty secret.''

Liberal Arts opens on December 13.