IF walls could talk, they’d have an intriguing yarn to tell about goings-on at the National Portrait Gallery this weekend.

Three actors, Ross Walker, Christopher Samuel Carroll and Jett Chudleigh, under the watchful eyes of director Katie Cawthorne and sound artist Jonah Myers, embarked on an examination of what exactly it is to view works of art in a gallery.

Unlike some of the NPG’s previous movement and dance forays into the galleries, where the performers interact with real paintings in the collection, this one takes place in the middle of blank walls, as the actors move around and study the non-existent pictures intently, occasionally muttering in appreciation or criticism.

At the beginning of the 20-minute performance there’s some interplay as Chudleigh, the novice viewer, is inveigled by Carroll into following suit and adopting the “proper” physical attitude for viewing art in a gallery. There’s more than a touch of satire, but their moments of deep contemplation and quietness tend to contest the common assertion that people spend less than 30 seconds on average looking at a work of art.

A shift of location to a conveniently-placed bench which becomes a plinth allows the actors to step inside some of the paintings. In the only segment using words, and not many of them, Carroll takes up his position on top of the bench as Princess Mary in Jiawei Shen’s “Portrait of HRH Crown Princess Mary of Denmark”, complete with flowing gown, Knight of the Order of the Elephant sash and earrings. We don’t see them but we imagine them and Carroll’s ability to stand stock still while we do so is uncanny.

In this segment the actors play with the “what if” scenario as Chudleigh attempts to entice Walker and Carroll, now playing portraits or sculptures, into moving out of their set attitudes into something else. They resist, but eventually comply and they all do a little jig with movements not unlike those made famous by John Travolta.

Finally it’s time for the actors to turn momentarily on to the audience and take a good, critical look at them before everyone heads to look at “real” portraits.

Whoever said that art gallery-going was a passive activity? This intriguing glimpse into the art of viewing turns that notion on its head.