Explained: Why we like to lock lips
FOR many, the moment Rhett Butler pulls Scarlett O'Hara into his arms for a passionate kiss is the most iconic lip-lock in silver screen history.
But that moment in the 1939 blockbuster Gone With The Wind is not entirely what it seems.
The actress portraying Scarlett, Vivian Leigh, did not enjoy kissing her co-star Clark Gable because he had dentures which caused notoriously bad breath, and she was heard complaining about filming their more passionate moments in between scenes.
If even the most sensual on-screen kiss is a lie, then what hope is there for the rest of us?
Why do people kiss? And what makes a good kiss?
What does it say about a relationship when there is a lot of kissing or no kissing?
Melbourne dating coach Chris Manak says that when it comes to kissing, our subconscious reactions are just as important, if not more important, than our conscious minds.
Our subconscious minds are much more accurate when it comes to recognising someone we have strong chemistry with and it can often tell from the moment two people's lips first meet.
"Significant areas of the brain light up when you're kissing someone," Manak said.
"A lot of subconscious activity goes on."
Manak said women are usually attracted to men with an opposing immune system because it enables them to have strong, healthy children.
Often people were attracted to one another, kissed, but felt instinctively that it wasn't quite right.
Humans, along with monkeys, are one of the few creatures on this planet who kiss.
In fact, a study undertaken by the American Anthropologist journal looked at 168 cultures from around the world and found that even among humans, only 46% of cultures kiss in the romantic sense.
The study disputed the belief that romantic kissing was a universal human behaviour, instead suggesting it seemed to be the product of western societies, passed on from one generation to the next.
But it's not just social conditioning that makes us want to kiss someone to whom we are attracted.
Scientist and love guru Samantha Jayne, who owns and operates a match-making and introduction service, said there were many nerve endings in the tongue and lip area which intensify the sensations we get from kissing.
Locking lips also makes us feel good, helps with bonding and reduces stress.
That all comes down to the release of a hormone called oxytocin when our lips meet.
Oxytocin is widely known as the love hormone or cuddle chemical.
Some people even purchase nasal sprays containing oxytocin to enhance positive feelings and social skills.
But it's not the only hormone released when we kiss.
Testosterone also gets released, which increases arousal.
The act of kissing can help men predict fertility, whether a woman is ovulating, while women use it to assess chemistry and DNA.
"Kissing can help you bond - and gather genetic information," Jayne said.
Pheromones also play an important part in picking a partner - simply enjoying the way someone else smells can play a huge role in attraction.
In fact, Jayne says if you have a laundry list of qualities you are looking for in a partner, you might as well tear it up right now.
"People have these massive laundry lists, he's going to have that or he's going to have this, but that laundry list has nothing to do with chemistry," she said.
Jayne recommends that her clients go on three dates before they share a first kiss with someone.
"The longer you spend with someone, the more you get rid of that laundry list and let chemistry happen," she says.
The good news is, there is no limit to how much you should kiss in a relationship.
In fact, the opposite is true, because kissing will increase the bonds of any relationship.
"The more you kiss in a relationship, the better it is," Jayne says.
"Women in particular look out for pheromones, some people smell so good, others smell weird.
"It's just compatibility, kissing is a great way to test that."
According to Jayne, a good kiss is a lot more important to women than men.
"Women place a lot of importance on a good kiss," she said.
"Men are more about the other physical interactions.
"Men can overlook a bad kiss."
There are scientists out there who study the phenomenon of kissing.
Philematologists aren't really sure why humans started locking lips, but Jayne says one theory is that it's part of evolution passed on from primate mothers.
The theory suggests primate mothers chewed food and passed it along to their toothless babies.
But kissing is now about a lot more than receiving sustenance.
"Kissing is about humans bonding, social bonding and love," Jayne said.
Maryborough's Julia Bate has kissed the same man each day for more than 65 years.
She will have been married to her husband, Cloyde, for 65 years in December and she said they still kissed every day. "I get a kiss good morning and a kiss good night," she said.
They have been together so long she can't remember their first kiss, but she does remember her dad throwing a bucket of water over them in their teens when they had been smooching a little too long.
Julia was 16 when she met her husband. The two struck up a relationship after Cloyde's mum spotted her in the drapery business where Julia was working.
She went home and told her son there was a nice girl working at the store and he should "make himself known to her".
Now, after 65 years, the couple have two children, two grandchildren and a four-week-old great grandchild and Julia said she still believed sharing a kiss, even if it was just a peck, was an important part of any romantic relationship.
Of course, like Vivian Leigh, actors know better than anyone that not all kisses are made equal.
Thespian Matthew Backer, who has appeared in many productions, including the critically acclaimed musical Jersey Boys, said kissing on stage was technical rather than passionate.
"For actors, it all depends on the scene and what's needed with the two characters," he said.
When rehearsing, sometimes an actor would have to kiss someone they had never met.
"It's very technical," Matthew said. "It's not like a kiss for a kiss's sake. It's just part of acting, the art of make believe."
But most of us don't have to worry about an audience - or ignoring a co-star's bad breath - when it comes to kissing someone we love.
And if it's with the right person - with the right pheromones - that oxytocin hit will give you one of the greatest feelings in the world.
Best movie kisses:
Gone With The Wind: "You should be kissed, and often. And by someone who knows how," Rhett Butler tells Scarlett O'Hara in what is widely considered the most iconic screen kiss of all time. What woman wouldn't want to hear those words?
From Here To Eternity: Burt Lancaster and Deborah Kerr's sandy, water-logged embrace has been replicated, and parodied, many times over. The sheer physicality of the scene, during which their characters passionately kiss on the beach as waves wash over them, makes it an enduring cinematic moment.
Titanic: Who could forget one of the most iconic scenes in James Cameron's Oscar-winning disaster epic, when Jack and Rose first cemented their romance while enjoying the freedom of standing on the steamship's bow.
Dirty Dancing: You have to wait the entire movie for it, but when Johnny returns to dance with Baby at the end of this 1987 cult classic and takes her into his arms, it's impossible not to swoon.
Ghost: Not even death could stop Patrick Swayze's character Sam from comforting his grieving partner Molly (Demi Moore) in a scene that must have boosted sales in pottery wheels.
Pretty Woman: Richard Gere and Julia Roberts made fire escapes sexy when their characters finally kissed at the end of Garry Marshall's romantic comedy about a businessman who falls in love with a prostitute.
When Harry Met Sally: This is that other memorable scene from Rob Reiner's comedy about two long-time friends (played by Billy Crystal and Meg Ryan) who finally give in to their feelings for one another.
The Notebook: They reportedly didn't get along on set, but Rachel McAdams and Ryan Gosling channelled that tension into their characters' memorable meeting in Nicholas Sparks' romantic drama.
Spider-Man: Tobey Maguire may not be remembered as the best Spider-Man, but his upside-down kiss in the rain with Kirsten Dunst will stand the test of time. But filming the kiss was a challenge, with water constantly running into Tobey's nose.
Twilight: There isn't a teenage girl, or many grown women for that matter, who hasn't watched Bella and Edward's first passionate kiss on repeat. Forbidden love between a girl and a vampire, what's not to like?