Grizzly Bear, Corn Exchange, Brighton

A Grizzly Bear gig is a civilised affair. The band thank us warmly for our support, pause to admire the venue's grand interior, and pay touching tribute to the city in which they find themselves ("Way to go, Brighton!"). Meanwhile, a grown-up, genteel and largely bespectacled audience murmurs approvingly. In Grizzly world, live performance is a serious business and those looking for a night of sweaty, beer-swilling rock'n'roll should probably seek a refund.

Grizzly Bear don't so much put on a show as conjure a series of atmospheres, ambling on to a stage decorated with scores of small glass lanterns that flicker on and off in tandem with the music's crescendos. Their opening number, "Southern Point", sets the mood with its keening vocals, delicate instrumentation and pulsing, psychedelic flourishes.

Their musical prowess is impressive, with flutes, clarinets and autoharps drifting in and out of the traditional guitars-keyboards-drums set-up. Stylistically, too, Grizzly Bear leave your head spinning as great acts of the past and present flip through your mind like a Rolodex: Paul Simon, Brian Wilson, The Band, Tim Buckley, Mercury Rev, Radiohead.

As well as proving that contemporary music doesn't have to be all about the middle-eight, the four-piece artfully skewer the rock-band archetype of a limelight-basking singer surrounded by three musical enablers, as they discreetly swap instruments throughout the set. Within this democratic arrangement, there are three singers – Ed Droste, Daniel Rossen and Chris Taylor – as well as a guest appearance from the support act, Victoria Legrand.

There are moments when the music loses its momentum. For all its psychedelic ambition, "Colorado" is a dirge during which the band lose themselves in the instrumentals and the dry ice, and seem to forget we are there at all.

But these moments are happily counteracted by more urgent tracks such as "Knife" and "Deep Blue Sea", during which the music's propulsive force ripples across the crowd. These are the times that define Grizzly Bear as one of the most interesting and inventive bands around. And what the foursome lack in old-fashioned showmanship, they make up for in amiability. It's not so much revenge of the nerds, as revenge of the nice guys. Who'd have thought it?