Manon de Boer, South London Gallery

A well-groomed, middle-aged woman walks into view and lights a cigarette. She stands, she smokes, the camera gives us a steady close-up of her face. As she appears to reminisce, her face subtly registers a range of emotions. Is she agitated, sad, irritated? She takes long drags of her cigarette. The film ends and she walks out of view. A second film begins. Same woman, same duration. A cigarette is smoked, the camera lingers on her face. She’s lost in recollection, but wait, there are subtle changes. A different backdrop.

This time the sunglasses, which had been perched on her head, have been replaced with a pink ribbon or a hairslide (though, perhaps, on recollection, these might have been worn in the first film, not the second). Her top isn’t the same either, though I’m not sure I can tell you in what ways it is different. But she certainly appears less uptight. At one point she tilts her head back and smiles. But then her face clouds over. She walks out of view. The end.

What are we to make of these two short, silent films? They are similar, but not the same. In fact, the differences are only slowly registered after several viewings. The work, Sylvia, March, 1 & 2, Hollywood Hills (main picture above), is filmed on 16mm film, giving it a soft, grainy texture, like home archive footage. We remember the broad picture, a few details remain vivid, but inevitably these details are jumbled. Memory, the woman’s and ours, is the theme we are asked to ponder.

We also recall Warhol’s Superstars, the series of fixed-lens films Warhol made of Factory hangers-on. His subjects squirmed, giggled, fidgeted, flirted with, or tried, on occasion, to brazenly stare the camera out. But the camera always seemed to get the better of them, exposing their vulnerabilities, their silly vanities.

The woman in Manon de Boer’s film is unlike any of Warhol’s Superstars. For all her subtle emoting, she remains coolly composed. Clearly, she is used to being in front of the camera, of which she seems to remain unaware. So, there is a clear sense of artifice. It’s not surprising to learn that she’s an actress. In fact, she's the veteran of Seventies soft-porn classic Emmanuelle. De Boer, a Dutch artist, made a feature-length film of Sylvia Kristel in 2005, in which the actress recollects versions of her life, and in these two distilled, soundless films, we’re invited to observe the subject as performer, inhabiting her own memories as a performance.

Indeed, just as we are invited to question the reliability of memory, we are also invited to ask what constitutes a performance. In another work de Boer recreates John Cage’s silent “composition” for piano, 4.33. Played twice, we first observe the pianist (pictured right), who is utterly absorbed, or affects utter absorption, in his task, then the individual members of the audience as the camera pans slowly round, finally settling on the view outside the studio window as the performance comes to a close. These works are slippery and elusive; sometimes they are driven simply by sound as the artist changes the film reel. This happens in Dissonant, in which a dancer rehearses to music heard purely inside her head. The dancer’s footwork and breathing provide the soundtrack, until at last she stops and we hear a rich burst of a violin sonata by Eugène Ysayë.

De Boer’s works are a rather flimsy palimpsest of ideas about the past, about memory, about acts of recollection. Like British artist Tacita Dean, her work has a very contemporary aesthetic preoccupation with film, though they are not quite beautiful or captivating. They modestly weave their thread of associations, then slip, all too easily, from memory.

• Manon de Boer at South London Gallery until 23 January