Does this picture frighten you? If so, you suffer from coulrophobia, a fear of clowns.

Last week police in Kent issued a warning over the use of Halloween masks after gangs wearing clown costumes were spotted jumping out of vans and deliberately scaring school pupils. They advised people to be alert, to stick to well-lit, busy areas and “look and act confidently… ‘walk tall’”.

While being scared of people jumping out of vans is quite rational – no matter what they may be wearing – studies suggest that up to 12 per cent of the population suffer from an irrational fear of clowns.

“People tend to have a negative outlook on clowns for some reason, which is a shame because we do great good,” says Clown Bluey, the UK’s favourite fool and funny clown (according to his website), who is based in Southampton with 32 years in the trade.

“I had never heard of the phobia, then about 10 years ago it was suddenly a fad, especially with teenage girls. They would see a clown and scream at the top of their voice. To me that always seemed to be attention-seeking and not anything to do with actually being frightened of clowns.”

Phobias are learned responses, which develop after a high level of fear is experienced in a situation where a certain stimulus is present. It is easy to see how a Jack-in-the-box or early children’s birthday party might sow a seed that grows into a phobia.

“Children can be nervous of Father Christmas or any dressed-up character until they get old enough to realise they’re not scary at all,” Clown Bluey adds. “Hollywood hasn’t helped. If you read the original Stephen King book It, only one boy sees a clown, all the other kids see is whatever they are afraid of. But of course Hollywood rewrote it so everyone sees the same clown.”

Clown Bluey emphasises that all he and his colleagues want to do is spread laughter, so why are they associated with completely opposite emotions? We are all scared of something but while arachnophobia (spiders) and acrophobia (heights) are understandable, an increasing number of people suffer from irrational fears such as globophobia (balloons), triskaidekaphobia (the number 13) and pogonophobia (beards), which is undoubtedly on the rise given the mushrooming number of hipsters around.

Chances are you are affected by nomophobia, the fear of being without mobile phone coverage, which more than 50 per cent of Brits admit to suffering from. But why are irrational fears of things that cannot harm us able to blight some people’s lives?

Dr David Lewis knows what you are thinking. A renowned psychologist, and chairman of Mindlab International, in the 1980s he pioneered the concept now known as neuromarketing, in layman’s terms – strapping electrodes to someone’s head and measuring their brainwaves.

“We have a fairly vanilla society,” he says. “Generally speaking, our lives are pretty bland and safe these days, certainly in the UK. As a result we lack primitive excitement.”

Lewis is referring to the adrenaline rush that comes from being scared. He believes irrational phobias are learned responses that in part fill the void left by our lives being drained of real dangers.

The word phobia comes from Phobos, who was the son of Ares, the Greek god of war. He was the personification of fear. Greek soldiers would paint his image on their shields to terrify their enemies. Throughout history, whether waging war or being surrounded by constant disease and death, fear was a major part of day-to-day existence. Now, in our mollycoddled culture, we pursue extreme sports, ride rollercoasters or, especially at this time of year, watch a scary film to reclaim the same sensation.

“I have been studying what I call ‘fun fear’ for the last 30 years, seeing why people enter situations where they are very scared, like going on a white-knuckle ride or to a horror film,” Lewis says. “Although you are emotionally fearful, intellectually you know you are not in any danger. You know the rollercoaster has been engineered to keep you perfectly safe; when you go to the cinema, however frightening the images appear on the screen, you know nothing is going to happen. The alien is going to pop out of the guy’s chest but it’s not going to attack you.”

Recent research by Empire Cinemas found that 20 per cent of people said the most scared they have ever been was in a cinema. Why do people actively seek out that feeling? “I think the survey is more a reflection on the pretty humdrum lives we lead,” Lewis says. “That is why when something unexpected happens in the real world we are so interested, for example people rubberneck road accidents. In a cinema you are not in any physical danger so you vicariously experience the excitement, the adrenaline buzz generated by the movie, as a pleasurable response.”

Is being scared, or at least experiencing the chemicals released in our bodies while we are scared, something we crave?

“Yeah we do,” Lewis says. “We get a buzz from adrenaline, some people get such a buzz they become adrenaline junkies, constantly putting themselves in situations where they can experience that buzz. Another neurotransmitter is dopamine, sometimes called the gas pedal of pleasure because the more you push it the more excitement you feel. That is why people become hooked on drugs or alcohol or high-energy foods. A film is not going to make you fat or addicted – it is a healthy way to experience excitement.”

Film-makers use a variety of tricks to generate a certain response in the viewer. A suspenseful build-up to a scare and unexpected occurrence triggers the startle response. As a reflex, your brain and body instantly change, the speed electrical signals move in the brain increases, as does your heart rate. Pupils dilate to let more light into the retina, muscles tense, your mouth will go dry and your palms will sweat.

“All these things are part of the fight-or-flight response that would be triggered by a physical danger but in this case they’re being triggered by an illusionary danger,” Lewis explains. “It’s like a battleship going into action stations. The captain takes crew away from nonessential departments, like the laundry or kitchen and sends them to man the guns.

“Essentially your body is doing the same to fight off a threat to its survival. It is believed your palms sweat because mild sweating increases the ability to grasp a branch if you are swinging from tree to tree. It makes the fingerprints swell up to give you a better grip. These are responses that originated thousands of years ago before we developed what we call civilisation.”

Experiencing ‘fun fear’ may have a beneficial effect, keeping your senses sharp. The military uses films (along with live ammunition training) to desensitise soldiers to the sights, sounds and smells they might encounter on the battlefield.

“They are horrendous movies, not the kind of films you see in the cinema,” Lewis says. “Sometimes they will inject aromas into the viewing area – blood and vomit and all sort of other things to make them better able to cope in a real-life situation.

“Commercial cinema is more about fun and enjoyment. As we move away from films and white-knuckle rides, where you are a passive respondent to the experience, to things where you take a more active part – skydiving, rock-climbing, bungee-jumping – there is a higher risk. This increased arousal can be beneficial to your survival because it makes you think more clearly and respond more rapidly.”

So embracing your fears is a wise thing to do. The more horror films you watch, the more it will take to scare you – and the more skilful film directors are forced to become to thrill their audience. And the more dates you go on, the less nervous you will feel.

“When I was a kid I was terrified of Doctor Who and would hide behind the sofa while what was basically a Tonka toy was dragged across the set on a piece of string,” Lewis says. “I think modern viewers need a lot more than that to be scared… but everybody is a bit anxious when they meet a person for the first time. On a first date you just have to suck it up.”

Kent Police had more practical advice – whether it comes to deterring Halloween tricksters, or that awkward first date, look and act confidently… walk tall.

Phobias

Phobias: How did Britain become a nation of scaredy-cats?