What influence does the time have on our response to cinema? I ask because the strangeness of A Headless Woman was compounded by seeing it at midday, when the mind feels at its most woken and conventional. A later viewing might have helped me to feel less prosaic. Darkness outside. The subconscious clocking in for its shift. These conditions are better suited to Lucrecia Martel’s artful, involving yet ultimately elusive film.

Set in Salta, her native province of Argentina, it concerns a middle-aged woman, Veronica, who hits something while driving along a deserted road. In stopping suddenly she bumps her head and enters a curiously disassociated state, cut adrift from memory, attachments, even sense of self. Or at least she thinks she has hit something. And the bump may be responsible for those symptoms, which anyway are increasingly open to doubt. Veronica, played by Maria Onetto with a dignified kind of bewilderment, struggles to cope with these uncertainties; has personal, professional and sexual contact with people without appearing to know why; then slips back into the stream of life, as if what had briefly felt strange were in fact normal. Which perhaps it is.

There are two mysteries here: (a) what happened on the road and (b) the film-maker’s intentions, both puzzles being illustrated by one particular image, emotive and teasingly deployed. After the incident a dog is shown lying in the road, although it is not clear if Veronica has noticed. Previously seen in the company of some boys, the dog appears to confirm and explain the collision, for our benefit at least. But as Veronica sits behind the wheel, dazed and unsure of what to do, one notices a child’s handprint on the glass beside her. Was it there before or is this the first time have we been shown the window from that angle? Not for the last time I doubted my powers of observation. Then, as Veronica sets off again, the first handprint is joined by a second. Is the director playing games with us or has some change in the light taken place, developing the prints like a photograph? Either way, there is an innocent explanation, given that she has just said goodbye to friends and their children outside a swimming pool, the little crowd milling round her car. Except that one of the boys seen playing with the dog is later found to be missing, in which case the prints might be his, a poignant trace of the impact, a different order of culpability. But would such perfect contact have been made by a glancing blow, palms pressed flat against the glass? And why does Veronica, and everyone else who examines the car, fail to notice them?

That is not a plot spoiler – there is little in the way of plot to spoil.  And nothing is really clarified or resolved. Seizing on this, the critics, largely enthusiastic about the film, have had fun trying to work out what it signifies. Being dentists, Veronica and her husband are well off by local standards, part of a middle class set with comfortable lives. As a result, her apparent ability to shrug off the accident has been interpreted as bourgeois indifference, even callousness, towards the poor, the boy having been an urchin, we understand, foul-mouthed and streetwise. In support of this view, her apparent recovery is triggered or signalled by the simple expedient of dying her hair, one’s conscience cosmetic like a facial or perm. ‘Is that your natural colour?’ someone asks, one of those throw-away remarks freighted with subtext, with connotation. What is more, the absence of a corpse, together with a police contact’s ignorance of the missing boy, takes us back to The Disappeared, who perished in their thousands under the former military regime, a reign of terror colluded in by ‘the haves’. From this angle, Martel is pursuing a political agenda, one that is coded to make it hard for us, or in fear of reprisals.

But this is a work of art, not propaganda, and a single reading of its complexities feels reductive, one-dimensional. Veronica’s dilemma following the accident might be anyone’s, irrespective of class. Guilt, wishful thinking, a willingness to be reassured: these are human attributes that comment on our shared condition. Likewise her disassociated state after the accident, which says something about identity. It is striking, almost comical, how her loss of memory goes unnoticed by the people she knows. They finish her sentences; anticipate what she is going to do; explain relationships by acting them out. Being close to others is to be created by them. We are what they take us to be, the self socially construed.

Coincidentally, or by a cute piece of programming, the Borderline Festival is also screening Blow Up, Antonioni’s head-scratcher from 1966 which features a body, and by implication a murder, that might or might not have been. The parallels are obvious, but not to be overdone. The context for that earlier exercise in bemusement was the vogue, new to popular culture, for taking drugs which questioned the nature of perception. The Headless Woman, a more oblique if less ground-breaking film, confronts a deeper unease and ambiguity. Sober or high, how do we know that what we experience is real? Through a chance event Veronica is gifted a vision of her life shorn of its surface meaning so that nothing about the world and one’s place in it seems straightforward or secure. In token of this, the diminutive by which everyone knows her is Vero. Nearly two thirds of Argentinians have some degree of Italian descent and ‘vero’ can be translated from that language as ‘true’. The name, once affirming the fact of herself, becomes ironic, in other words, the nature of who we are revealed to be fluid, contingent, unknowable. Yet Martel’s female protagonist, like some everywoman suffering on our behalf, reverts to being a mannequin or avatar, the role created for her by the world. Class loyalty or existential bind, what else can she do? When hair has been dyed so often, who knows what is natural.