Since HG Well's 1897 novel The Invisible Man, the world of science fiction has been fascinated with the idea of disappearing from view.

And while experts attempt to invent invisibility cloaks, a team of researchers has discovered it's possible to trick a person into thinking they're invisible simply by using a virtual reality headset.

The study also found that creating an illusion of invisibility can help people deal with socially stressful situations more easily.

Participants wore a virtual reality headset while looking at their body. Instead of seeing their body, they were shown an empty space (left) or a mannequin (right). A researcher stroked their body while moving another brush in the corresponding location in the empty space, as if they were touching an 'invisible body'

Neuroscientists from Sweden's Karolinska Institutet asked 125 people to wear a virtual reality headset while standing upright and to look down towards their body.

Instead of seeing their body, they were shown either the body of a mannequin or an empty space where their body should have been.

A researcher then stroked the participant's body with a large paintbrush while simultaneously moving another paintbrush in the corresponding location in the empty space below the cameras, as if they were touching an 'invisible body'.

This researcher applied touches to five different body parts, including the abdomen, the left and right lower arms, and the left and right lower legs and feet.

THE INVISIBILITY ILLUSION Neuroscientists asked people to wear a virtual reality headset while looking at their body. Instead of seeing their body, they were shown either the body of a mannequin or an empty space where their body should have been. A researcher then stroked the participant's body with a large paintbrush while simultaneously moving another paintbrush in the corresponding location in the empty space below the cameras, as if he were touching an 'invisible body'. Following these experiments the participants were asked to rate how they perceived their body from -3 to 3. These included: 'I felt the touch of the brush in the empty space/on the mannequin in the location where I saw the brush moving'

'It felt as if I had an invisible body/the mannequin's body were my body'

'I experienced that the touch I felt was caused by the brush moving in the empty space/touching the mannequin'

'When I saw the brush moving, I experienced the touch on my back'

'It felt as if I had two bodies' and

'I could no longer feel my body' The first three questions were 'illusion statements', while the second three were 'control statements'. Ratings were high for all three illusion statements during the 'invisible body' experiment and positive, albeit lower, for all questions in the mannequin experiment except when during the asynchronous condition. Advertisement

The duration of each individual brushstroke was one second and the time between the offset of one touch and the onset of the next touch was 1.5 second to make sure there were no overlaps between the seen and felt touches.

This was known as the 'synchronous condition'.

During a second experiment, known as the 'asynchronous condition', the brushstrokes in the empty space were delayed by 1.25 seconds following the physical touch.

And during the 'incongruent condition' the touches on the participant’s real body were applied in the opposite direction and on another body part than the one being seen.

This was repeated with the mannequin to see if the participant would equally 'take ownership' of the mannequin's body even if it looked different to their own.

Following these experiments the participants were asked to rate how they perceived their body from -3 to 3.

These included: 'I felt the touch of the brush in the empty space/on the mannequin in the location where I saw the brush moving' (S1), 'It felt as if I had an invisible body/the mannequin's body were my body' (S2), 'I experienced that the touch I felt was caused by the brush moving in the empty space/touching the mannequin' (S3), 'When I saw the brush moving, I experienced the touch on my back (S4), 'It felt as if I had two bodies (S5) and 'I could no longer feel my body' (S6).

The first three questions were illusion statements, while the second three were control statements.

Ratings were high for all three illusion statements during the 'invisible body' experiment and positive, albeit lower, for all questions in the mannequin experiment except when during the asynchronous condition.

The researchers said this proved the illusion had been successful.

The opposite was true for the control statements, in which all ratings were zero or below except for the asynchronous condition in the mannequin experiment for the question: 'It felt as if I had two bodies'.

'Synchronous' was when the real and simulated strokes occurred at the same time, when there was a delay it was known as 'asynchronous'. Following these tests participants were asked to rate how they perceived their body at each point based on a series of illusion-based statements and control statements (shown)

Ratings were high for the illusion statements during both the 'invisible body' and mannequin experiments. This graphic represents how the participants perceived their body during synchronous and asynchronous mannequin test (red and pink), and the asynchronous and synchronous invisible test (light green and green)

'Within less than a minute, the majority of the participants started to transfer the sensation of touch to the portion of empty space where they saw the paintbrush move and experienced an invisible body in that position,' said Arvid Guterstam, lead author of the study.

'We showed in a previous study that the same illusion can be created for a single hand. The present study demonstrates that the 'invisible hand illusion' can, surprisingly, be extended to an entire invisible body.'

To demonstrate the effectiveness of the illusion, the researchers additionally made a stabbing motion with a knife toward the empty space that represented the stomach of the invisible body.

In another part of the study the researchers examined whether the feeling of invisibility can play a role in social anxiety by placing the participants in front of an audience of strangers. They found the heart rate of those how had exeprienced the invisible body illusion was lower than when they had a physical body

The participants' sweat response to seeing the knife was elevated while experiencing the illusion but absent when the illusion was broken, which suggests the brain interprets the threat in empty space as a threat directed toward one's own body.

In H.G. Well's The Invisible Man, protagonist Griffin turns himself invisible and ultimately goes insane

In another part of the study the researchers examined whether the feeling of invisibility can play a role in social anxiety by placing the participants in front of an audience of strangers.

'We found that their heart rate and self-reported stress level during the 'performance' was lower when they immediately prior had experienced the invisible body illusion compared to when they experienced having a physical body,' added Mr Guterstam.

'These results are interesting because they show that the perceived physical quality of the body can change the way our brain processes social cues.'

The researchers said they hope the results of the study will be of value to future clinical research, for example in the development of new therapies for social anxiety disorder.

The paper continued: 'Recent advances in materials science suggest that invisibility cloaking of the human body may be possible in the not-so-distant future.

'However, it remains unknown how invisibility affects body perception and embodied cognition. To address these questions, we developed a perceptual illusion of having an entire invisible body.

'This study provides an experimental model of what it is like to be invisible and shows that this experience affects bodily self-perception and social cognition.'

Principal investigator Dr. Henrik Ehrsson, professor at the Department of Neuroscience added that follow-up studies should investigate whether the feeling of invisibility affects moral decision-making, to ensure that future invisibility cloaking does not make us lose our sense of right and wrong.