While We're Young, film review: Ben Stiller is in his element in generation-gap comedy

Noah Baumbach's new film is something like a mash- up of his previous two: Greenberg, which was about a depressed middle-aged guy; and Frances Ha, which was about a directionless twentysomething. It's a generation-gap comedy in which a fortysomething failing documentary maker (Ben Stiller) and his wife (Naomi Watts) are befriended by a twenty-something aspiring documentary maker (Adam Driver) and his wife (Amanda Seyfried).

It takes as its epigraph some Ibsen dialogue about the horror and fear with which the middle-aged regard the generation below them. But it is Baumbach's least sour and most generous spirited film so far, and in fact the older couple, Josh and Cornelia, are invigorated by the younger couple, Jamie and Darby, and flattered to be in their company.

It's easy to point and laugh at old people when they try to get down with the kids, and indeed, whether Josh is vomiting during an ayahuasca ceremony or injuring his back when trying to keep up Jamie on a bicycle, it has some of Stiller's funniest work in ages.

But the film is also full of smart comic writing and keen observations of the differences between Generation X and the Millennials, and it also seems genuinely interested in a rapprochement. Audiences of either age group may wince to see their own tastes and foibles and attitudes up on screen, but they don't get to sneer at members of the other one.