Death metal has a reputation. Its lyrics and imagery revel in a stomach-churning zone of ultra-violence, profanity, and torment.

We're talking crushed skulls. Slit throats. Mutilated everythings and violated etceteras. What kind of effect does this nightmarish barrage have on people who listen to the music?

According to new research by psychologists from Macquarie University in Australia, death metal isn't a demonic influence – even if its themes are concerned with little else.

In an experiment with 80 people, the researchers wanted to investigate whether death metal and heavy metal fans would be desensitised to the violent subject matter of the music they listen to – a common concern about violence in other forms of pop culture, such as video games and cinema.

"It is suggested that long-term exposure to violent media may decrease sensitivity to depictions of violence," the team explains in a new paper.

"However, it is unknown whether persistent exposure to music with violent themes affects implicit violent imagery processing."

To investigate, the researchers used a technique called binocular rivalry, which tests for perceptual dominance when two different images are shown to a viewer at the same time, each one being displayed to a different eye.

When this happens, visual input from one eye usually dominates over the image seen by the other eye – an experiment that is "uniquely powerful", the researchers write, "in that it provides a robust index of a subcortical processing bias".

"By measuring the amount of time that each image is dominant (or suppressed), it is possible to determine which visual input the brain is prioritising for conscious experience," the paper explains.

In the study, the team recruited 32 fans of death metal and heavy metal, along with 48 non-fans, and tested them with a binocular rivalry experiment, which showed them violent and neutral images simultaneously while they listened to music.

Much like the images were contrasting, so was the music played, with the participants listening to "Happy" by Pharrell Williams (a ubiquitous earworm featured on a kids movie soundtrack) or "Eaten" by Swedish death metal supergroup Bloodbath.

"Eaten" is rather less ubiquitous, probably because of lyrics like this:

I've had one desire since I was born

To see my body ripped and torn

To see my flesh devoured before my eyes

Only for you I volunteer as a human sacrifice

Carve me up, slice me apart

Suck my guts and lick my heart

Chop me up, I like to be hurt

Drink my marrow and blood for dessert

During the experiment, the participants would press buttons to indicate whether they perceived the violent image, or the neutral image.

What the researchers found was that both fans and non-fans of death metal tended to display a bias, perceiving the violent imagery over the neutral imagery they were shown, and this happened regardless of the music they were listening to.

"Thus, we observed no evidence that fans of violent music are generally desensitised to violence, in that such desensitisation should have been reflected in the absence of a bias for processing violent imagery for fans of violent music," the authors explain.

"This finding raises doubts about arguments that long-term exposure to violent media may desensitise consumers to violence."

That's good to know, and it's somewhat in sync with previous findings made by the members of the same research team.

Even while death metal lyrics frequently concern topics like rape, infanticide, and necrophilia, listening to the music has been shown to arouse "positive experiences such as power, joy and peace" in fans, one of the researchers, psychologist Bill Thomson, explained in The Conversation last year.

"[Death metal] fans are nice people," Thompson told the BBC this week. "They're not going to go out and hurt someone."

The findings are reported in Royal Society Open Science.