The latest Brad Pitt block-buster movie World War Z - about a zombie apocalypse sweeping the world - has just opened in the UK. But does the immense global popularity of horror genre films like these reveal something dark lurking in our psyches?
In a paper entitled Monsters Evolve: A Biocultural Approach to Horror Stories, Mathias Clasen from Aarhus University, recently argued that evolution has programmed our brains to be alert to, and fascinated by, violent danger in our environments. There was survival value in such hyper-vigilance.
The paper published in the academic journal Review of General Psychology, points out that the best way to get a sense of what life was like for hundreds of thousands of years for our ancestors, is to look at the everyday experiences of modern day so-called, primitive, hunter-gatherer tribes. A recent study of such foragers in Paraguay found 55% of all deaths were due to violence in one form or another.
Horror films, according to this theory, exploit our brains being wired up by our evolutionary past, to be gripped by any possibility of violence.
What is particularly powerful about this evolutionary theory is that it follows that what scares us is remarkably similar, no matter what culture across the world we hail from. This is very different from what makes us laugh.
If you try watching a comedy film in a foreign language and from another culture, you're unlikely to find it anywhere near as amusing as one where you understand the language and the way of life. However, try watching a horror film under similar conditions, and even if you know nothing of the speech or society about which it's made, you're still likely to become scared.
But are there even murkier psychological reasons for why horror films are regarded within the industry as the most consistently performing Hollywood genre at the box office?
A study of 50 'Slasher' Horror films released in North America between 1960 and 2007, entitled Sex and Violence in the Slasher Horror Film: A Content Analysis of Gender Differences in the Depiction of Violence, found female characters were more likely, compared to male, to be victimized in scenes involving a concomitant presentation of sex and violence.
The study by Dr Andrew Welsh, from the Department of Criminology and Contemporary Studies at Laurier Brantford University in Canada, argues that the origins of the modern 'slasher' movie can be traced back to Alfred Hitchcock's Psycho (1960).
It's infamous shower scene introduced the basic plot elements of the male killer and the helpless female victim. These were to recur again and again in subsequent lucrative Horror film franchises including the Texas Chainsaw Massacre, Halloween, and Friday the 13th.
Welsh argues that frequent depictions of nudity and immoral behaviour by victims, unfamiliar locations, sudden death scenes designed to maximize shock, have defined the slasher film formula since 'Psycho', and were all present in the original.
Welsh's study selected randomly 50 slasher horror films from the Internet Movie Database (IMDb) and 1960 was chosen as the starting point because Alfred Hitchcock's Psycho, generally regarded as the first 'slasher' horror film, was released then.
The findings of the study, published in the Journal of Criminal Justice and Popular Culture, include that forms of psychological aggression, such as intimidation, stalking, or chasing, disproportionately involved female characters compared to male. Violent interactions involving female victims were significantly longer in duration as compared to those involving a male victim.
The study concludes that female characters in slasher horror films are significantly more likely to be victims in scenes involving sex and violence, as compared to male characters. Female characters are far more likely to be partially or fully naked and, when sexual and violent images are present, a woman is more likely to be the victim of attack.
This study of slasher horror films, reinforces concerns about women being frequently depicted in states of abject terror and helplessness.
But the slasher horror 'formula' also includes the final surviving character usually being a woman. This is so common that she is referred to as the 'Final Girl'. Welch points out that other researchers are concerned that the surviving female character tends to possess 'idealized virginal qualities', distinguishing her from other non-surviving female characters. The underlying message is that female characters who defy traditional gender roles by engaging in assertive and/or promiscuous sexual behaviour, are punished.
This plot device appears to be echoed back in the original horror slasher movie - Psycho.
Zombie movies have also been subject to similar psychological analysis, and it's notable that ancient evolutionary fears of predation, contagion and the dead are all neatly combined by zombies. Such creatures being unequivocally bad and requiring terrific violence to dispatch them, might also appeal to unconscious aggressive motivations within us.
Christian Jarrett writing in The Psychologist, published by the British Psychological Society, points out in an article entitled, 'The lure of horror', zombies actually originated in Haiti. In reality they appear to have been the seriously mentally ill.
The fact horror films violate all everyday moral codes may be precisely their attraction. They provide a playground where we can indulge in the fantasy of not being governed by ethical complexity and rules.
Because when you are facing death, life becomes refreshingly simple.
If you are interested in joining a conversation on these themes, visit http://www.meetup.com/The-UK-CBT-Group/events/124146392/ to book tickets for a screening of the original Psycho followed by a discussion open to the public chaired by Raj Persaud. In the audience will be members of the public as well as psychologists, psychotherapists and psychiatrists, at the Royal Society of Medicine, 1 Wimpole Street, London, W1 on 25 June at 6.30 for 7.00 pm - wine and canapés will be served.