Halloween 2014: What makes Ouija boards, demon dolls, and evil clowns so frightening?

It is a seemingly perverse instinct: paying £12 to enter a darkened room and be subjected to images specifically engineered to terrify you for 90 minutes. The good news is that you aren't a masochist, or (worse) a sadist. The allure of horror movies stems from an entirely natural impulse, honed by millions of years of evolutionary psychology.

Fear keeps us alive and competitive as a species, compelling us to avoid danger and anticipate attack, making us fearful of pain, afraid of death, and cautious of the unknown. "We're pumped full of adrenalin and cortisol during a horror film," says Dr Michael Sinclair, the clinical director at City Psychology Group. "Our 'fight or flight' impulse kicks in, our amygdala becomes very active and our heart races. Afterwards, we can feel a genuine sense of accomplishment."

But fear can also perform a social function, by reinforcing behaviours that are biologically advantageous, making us wary of outside threats, and prohibiting against socially deviant acts, such as murder and incest.

Looking at this year's crop of Halloween-hooked horror releases, which include a demonic doll, a haunted book, a Ouija board and subterranean ghosts, the plots are almost touchingly familiar. And all the more terrifying for it. Because a successful horror relies on the interplay between the familiar and the unknown. "Repetition or intertextual referencing doesn't weaken a horror premise or convention," explains Dr Johnny Walker, the author of Contemporary British Horror Cinema: Industry, Genre & Society. "It's the familiarity, the force of repetition, the self-referential nature of horror, that reassures us that we're safe during this ride."

James Watkins, the British director whose recent films include The Woman in Black (2012) and the hicks-in-the-sticks nightmare Eden Lake (2008), says that many recent horror films have been gory and nasty. "And I don't use these words in a pejorative sense at all – but this isn't necessarily the same thing as scary. Scary is letting people's imagination go to work in terms of shadows and what's in the shadows, what's lurking, what's in the unknown. I've always contended that what we can shoot is never going to be as scary as what people can imagine."

Here, Drs Sinclair and Walker with the help of Greg Buzwell, the co-curator of The British Library's Terror and Wonder: The Gothic Imagination exhibition, explain why horror tropes terrify:

"Abandoned settings are perfect for horror films," says Buzwell. "The old castle, remote cabin and the creepy mansion immediately put you back into the past and a more superstitious age; taking you away from modern comforts and easy communication with friends and neighbours. The isolation heightens the sense of fear, while old, dark houses are, by their very nature, full of shadows and dark corners. Horror films with modern settings often work well – Alien, for example, is a superb 'haunted-house in space' movie – but castles and creepy isolated mansions have atmosphere in spades." Dr Sinclair adds: "We inherently feel safer when we're connected to others, and in evolutionary terms, our sense of safety was very dependent on packs, groups. We know we're less likely to survive alone, and so films exploring isolation, being cut off and removed from all we know really threaten our sense of security."

The Babadook, a box-office and critical triumph this year, occupies the familiar territory of a hallucinatory child, with echoes of The Shining (1980), A Nightmare on Elm Street (1984) and The Others (2001). One function of horror is to reinforce notions of good and evil – and sometimes this is best achieved by subverting the most cherished of societal ideals, such as the inherent goodness of children. "Possessed children feature very strongly in [the] Gothic [exhibition]," Buzwell says. "There is something about innocence corrupted that is particularly disturbing – it runs counter to all our safe and civilised views of the world. Evil in adults is, sadly, all too common, but evil in children still has the power to genuinely shock. We, as adults, always feel protective towards children. The idea that we may actually need protecting from them is deeply disturbing – and a gift for novelists and film-makers." "It's a complete contradiction to our belief system," Dr Sinclair agrees.

The Evil Doll

The demonic doll from last autumn's smash The Conjuring, who also gets an airing in this year's Annabelle, is a direct descendant of Chucky from Child's Play (1988), who in turn is the progeny of Hugo, the ventriloquist's dummy in 1945's Dead of Night. "It's hugely disturbing to watch cherished childhood symbols – like dolls, books or toys – subverted into a sinister presence," Dr Sinclair says. "These are images that conventionally comfort and reassure, and it really challenges our assumed sense of safety, our nostalgic memories of fun and laughter, confronting us with the idea that we can't trust them after all."

The reason that it's such a successful horror device is because we want to be challenged, to be kept on our toes, to be reminded that we can't trust anything. "There's always been something compelling and cathartic about plots where trust is betrayed, because we feel like we're preparing ourselves for future traumas and betrayals by enduring this one, second-guessing future challenges," Dr Sinclair adds.

The Bad Clown

The fourth series of television's American Horror Story takes its setting as a 1950s travelling freak show, with a murderous clown as the bogeyman, eerily reminiscent of Stephen King's 1986 novel (and the 1990 film adaptation) It.

The clown is a double whammy of horror: a childhood symbol subverted which taps into the idea of the "uncanny", ie that something looks almost right, and almost safe, but not quite. "The element of disguise, not being able to judge someone's emotions – and, therefore, their intentions toward us – is inherently threatening," Dr Sinclair says. Clowns and masks have the capacity to provoke fear because their make-up conceals their true facial emotions, thus thwarting our instinctual desire to read other people's minds through their faces. "This cripples our ability to judge our security in a situation," Dr Sinclair says

The Ouija Board

"Spiritualism really takes flight in the 1850s and 1860s, partly in response to increasing doubts about the existence of God (and thus in an afterlife). Ouija boards and seances attempted to fill the gap in a world rendered mechanistic by the theories of people like Charles Darwin," Buzwell says. "But that sense of needing to know what follows death is a universal concern. I think a lot of films and books about ghosts and spirits really feed into our fear of the unknown, and perhaps death, and what may lie beyond death, is the greatest unknown of all."

"Deliverance, The Last House on the Left and more recently Eden Lake all rely on media representations of a class or community that we don't understand, where we don't belong," Dr Walker says. The message is brutal: civilised society as we know it is a fairly weak, flimsy construct, and we don't need to stray too far out of our comfort zone to find a bunch of crazed yokels out to get us. "It's very threatening to us as animals to find ourselves out of society, isolated – the unknown, the sense of being a fish out of water, being unfamiliar with the rules in this new place: this all taps into a very primal fear about our place in society," Dr Sinclair adds.