Actors speak, extras don’t. Actors can look at the camera, extras can’t. Actors have depth, extras are all surface. Actors matter, extras don’t.

The 12 works in Actors & Extras all question these assumptions, either pushing at the boundary between the two roles or inverting them, bringing the extra into the spotlight. Most are video installations, and, while you can just dip into them, it’s easy to spend hours exploring everything they have to say.

Some of the pieces are beautifully simple, such as Krassimir Terziev’s “Remote Resemblances”, a collection of photographs from the files of a Bulgarian talent agency. Each potential extra holds a card with his or her name, height and telephone number, looking into the camera in a way that would not be allowed if they were cast. Children are accompanied by adults who do not have cards, appearing as extras themselves.

Similarly, Portuguese artist João Onofre’s “Casting” shows a group of young models waiting to step up to a camera and say a phrase, crossing the line between silent extra and performing actor as they do so.

Two of the most interesting pieces relate directly to the experience of the Hollywood production process. Terziev’s “Background Action” explores the bizarre role of extras in Wolfgang Petersen’s 2004 epic Troy. Filming was meant to take place in Morocco, but then the war in Iraq kicked off, and everything relocated to Mexico. The director still needed lots of fit, Mediterranean-looking guys to front the vast Greek and Trojan armies, and so 300 Bulgarian athletes were recruited and flown to Mexico for the three-month shoot.

Terziev uses interviews with the extras to explore the cultural and geographical dislocation involved, from the impact they had on the local population to the difficulty they sometimes experienced remembering that it was all just a film. The similarities with a real army, sent to a distant country to fight, are all too apparent. In addition to the interviews, there are photographs and home videos made by the extras. One video of an extra advancing towards the camera across a field has been installed in a mirrored cabin, so that the single figure is infinitely multiplied on either side.

Israeli artist Omer Fast’s “Spielberg’s List” explores the massive set built by Steven Spielberg to make Schindler’s List, recreations close to the original sites of the Krakow ghetto and Plaszow concentration camp. Nearly 20 years on, both are still standing and have become a tourist attraction. Part of this video installation follows a party of visitors on a guided tour, alongside interviews with locals who were extras in the film.

There is a sinister echo of films memorialising the Holocaust, with witnesses to Spielberg’s production replacing those of real survivors, and fragments of the original movie intruding in the same way as newsreel footage. The effect of Hollywood recreating this devastating event on the spot, with people whose parents and grandparents would have been involved in one way or another, is never far from the surface.

The effect is multiplied by another exhibit, a propaganda film made by the Nazis in 1944 to show the world what a model community they had created for the Jews in the Czech ghetto town Terezin. Here the “extras” were all inmates of the ghetto and, like the director Kurt Gerron, most ended up in Auschwitz. While not an “art work” in the same way, it makes a powerful companion piece: a real ghetto made to look false alongside a false ghetto made to look real.

Another theme is the way in which people are actors and extras in political events. Romanian artist Irina Botea matches TV footage of her country’s 1989 revolution with recreations staged with students at the Art Institute of Chicago. There is a telling sense of confusion and unreality in both sets of “performances”.

Better still is The Battle of Orgreave, a film by Mike Figgis documenting the re-creation by British artist Jeremy Deller of a notorious 1984 clash between police and striking miners in South Yorkshire. Some of the participants in the re-creation participated in the original event, and feelings run high as they reprise their roles in the same location. Jokes about winning this time around are clearly heartfelt.

Until 19 December
Argos Centre
for Art and Media
Werfstraat 13, Brussels
www.argosarts.org