You start by picking up the knife, or reaching for the neck of a broken-off bottle. Then comes the lunge and wrestle, the physical strain as your victim fights back, the desire to overpower him. You feel the density of his body against yours, the warmth of his blood. Now the victim is looking up at you, making eye contact in his final moments.

Science-fiction writers have fantasised about virtual reality (VR) for decades. Now it is here – and with it, perhaps, the possibility of the complete physical experience of killing someone, without harming a soul. As well as Facebook’s ongoing efforts with Oculus Rift, Google recently bought the eye-tracking start-up Eyefluence, to boost its progress towards creating more immersive virtual worlds. The director Alejandro G Iñárritu and the cinematographer Emmanuel Lubezki, both famous for Birdman (2014) and The Revenant (2015), have announced that their next project will be a short VR film.

But this new form of entertainment is dangerous. The impact of immersive virtual violence must be questioned, studied and controlled. Before it becomes possible to realistically simulate the experience of killing someone, murder in VR should be made illegal.

This is not the argument of a killjoy. As someone who has worked in film and television for almost 20 years, I am acutely aware that the craft of filmmaking is all about maximising the impact on the audience. Directors ask actors to change the intonation of a single word, while editors sweat over a film cut down to fractions of a second, all in pursuit of the right mood and atmosphere.

So I understand the appeal of VR, and its potential to make a story all the more real for the viewer. But we must examine that temptation in light of the fact that both cinema and gaming thrive on stories of conflict and resolution. Murder and violence are a mainstay of our drama, while single-person shooters are one of the most popular segments of the games industry.

The effects of all this gore are not clear-cut. Crime rates in the United States have fallen even as Hollywood films have become bloodier and violent video games have grown in popularity. Some research suggests that shooter games can be soothing, while other studies indicate they might be a causal risk factor in violent behaviour. (Perhaps, as for Frank Underwood in the Netflix series House of Cards (2013-), it’s possible for video games to be both those things.) Students who played violent games for just 20 minutes a day, three days in a row, were more aggressive and less empathetic than those who didn’t, according to research by the psychologist Brad Bushman at Ohio State University and his team. The repeated actions, interactivity, assuming the position of the aggressor, and the lack of negative consequences for violence, are all aspects of the gaming experience that amplify aggressive behaviour, according to research by the psychologists Craig Anderson at Iowa State University and Wayne Warburton at Macquarie University in Sydney. Mass shooters including Aaron Alexis, Adam Lanza and Anders Breivik were all obsessive gamers.

The problem of what entertainment does to us isn’t new. The morality of art has been a matter of debate since Plato. The philosopher Jean-Jacques Rousseau was skeptical of the divisive and corrupting potential of theatre, for example, with its passive audience in their solitary seats. Instead, he promoted participatory festivals that would cement community solidarity, with lively rituals to unify the jubilant crowd. But now, for the first time, technology promises to explode the boundary between the world we create through artifice and performance, and the real world as we perceive it, flickering on the wall of Plato’s cave. And the consequences of such immersive participation are complex, uncertain and fraught with risk.

Humans are embodied beings, which means that the way we think, feel, perceive and behave is bound up with the fact that we exist as part of and within our bodies. By hijacking our capacity for proprioception – that is, our ability to discern states of the body and perceive it as our own – VR can increase our identification with the character we’re playing. The ‘rubber hand illusion’ showed that, in the right conditions, it’s possible to feel like an inert prosthetic appendage is a real hand; more recently, a 2012 study found that people perceived a distorted virtual arm, stretched up to three times its ordinary length, to still be a part of their body.

It’s a small step from here to truly inhabiting the body of another person in VR. But the consequences of such complete identification are unknown, as the German philosopher Thomas Metzinger has warned. There is the risk that virtual embodiment could bring on psychosis in those who are vulnerable to it, or create a sense of alienation from their real bodies when they return to them after a long absence. People in virtual environments tend to conform to the expectations of their avatar, Metzinger says. A study by Stanford researchers in 2007 dubbed this ‘the Proteus effect’: they found that people who had more attractive virtual characters were more willing to be intimate with other people, while those assigned taller avatars were more confident and aggressive in negotiations. There’s a risk that this behaviour, developed in the virtual realm, could bleed over into the real one.

In an immersive virtual environment, what will it be like to kill? Surely a terrifying, electrifying, even thrilling experience. But by embodying killers, we risk making violence more tantalising, training ourselves in cruelty and normalising aggression. The possibility of building fantasy worlds excites me as a filmmaker – but, as a human being, I think we must be wary. We must study the psychological impacts, consider the moral and legal implications, even establish a code of conduct. Virtual reality promises to expand the range of forms we can inhabit and what we can do with those bodies. But what we physically feel shapes our minds. Until we understand the consequences of how violence in virtual reality might change us, virtual murder should be illegal.