When was the last time you felt really uplifted, like you believed happy endings could be possible? When was the last time you cried? Okay, maybe you live a dynamic, emotionally complex and fulfilling life but for most of us it was probably on a trip to the cinema.

Cinemas are where we experience the greatest range and concentration of emotion (I’m not just talking about whether or not you were stood up by your Tinder date). But how and why do films alter our mood more dramatically than real-life experiences?

When released in the US last month, Inside Out took more money in its opening weekend than any other original Pixar film, with audiences laughing and crying in equal measure. The storyline is simple: a young girl called Riley and her family move from Minnesota to San Francisco. That’s pretty much it as far as the plot goes. Most of the action takes place inside Riley’s head where her emotions – Joy, Sadness, Anger, Fear and Disgust – attempt to navigate this tumultuous period in her life when she is forced to grow up and leave her childhood behind.

Growing up and loneliness are themes Pixar films have squeezed tears out of before. Just think about Andy giving up his beloved playmates in Toy Story 3, the thought we might never find Nemo and the heart-crushing opening sequence of Up. Inside Out ratchets the poignancy to new heights but what does Pixar gain from putting audiences through the emotional wringer? Inside Out asks quite literally what is going on inside our heads – but what is going on inside Pixar’s?

“Storytelling is what we do,” says Ronnie Del Carmen, who co-directed Inside Out. “Most of the five years it took us to make this movie was about trying to make sure we had a good story. That is the part that takes the longest – animating the movie only takes about a year and a half. We have a very rigorous system.

“We tell our stories in story reels – like a real movie but drawn because it’s cheaper – and we screen that every three months. Parts that are working we keep, if something’s wrong we change it. You get better at telling your movies by doing it over and over again.”

Del Carmen’s first film-making experience was as far from Pixar’s precisely perfect production process as possible. As a 15-year-old growing up in the Philippines, Del Carmen joined the art department of the infamously chaotic Apocalypse Now shoot.

“I was a grunt painter doing all the jobs nobody wants to do – painting props, signs, ageing things – one of a vast number of minions that you get to do these little jobs,” he says. “It could not be further from working on a Pixar movie. It was definitely more dangerous.”

But is there anything riskier than creating a children’s film that takes place in the abstract world of the mind? Pixar has consistently raised the bar for animated films but in many ways Inside Out is their most ambitious work. “I think it maybe is,” Del Carmen agrees. “We wanted to make sure that we weren’t just being clever for clever’s sake. We screened it for our employees’ children and afterwards they explained the movie back to us in terms that were more accurate than we did.

“It was such a joy to hear the children tell us that Joy was trying to keep Riley happy all the time and that was not working. When you’re experiencing our stories you respond to it emotionally, whether it’s happiness or anger or indignation or indifference, it should be the thing I want from the audience.”

To explain how Pixar and films in general manage to push our emotional buttons so effectively, we can go back to the very birth of cinema. Emotion is at the core of motion pictures. Don’t take my word for it, here is Russian film pioneer Sergei Eisenstein (pictured below) writing in the 1930s: “[The phenomenon of emotion] is completely identical with the primary phenomenon of cinema. There, movement is created out of two motionless cells. Here, a movement of the soul, i.e. emotion (from the Latin root motio = movement), is created out of the performance of a series of incidents.”

Right. So to understand how film works, we have to understand how emotion works. Dr Rachael Jack likes to talk about her feelings. She and her team at the University of Glasgow’s Institute of Neuroscience and Psychology have studied how many emotions we have and why they developed in the first place.

“Communicating emotions is really important because it allows others in our environment to adjust their behaviour accordingly so that we can have smooth and successful inter-actions,” she says. “The survival of the human race is ultimately due to forming groups – only one man leaving Africa to populate the world would be highly risky, if not totally impossible. Evolutionary growth and strength based on forming groups is seen in many other animals – and in physics: 1,000 hairs together are stronger than one.”

There are various theories about how many emotions humans have. Dr Jack’s recent research suggests we may have hundreds of emotions but all connected to four basic states: happiness, sadness, anger and fear. “From those, all others are built,” she says. “Humans are highly complex and sophisticated social beings, so our emotional experiences are commensurately complex and nuanced. Facial expressions likely started as an adaptive behaviour to benefit the expresser.

“For example, opening the eyes wide increases visual information and could help with identifying escape routes; wrinkling the nose blocks the nasal cavity and so reduces inhalation of pathogens. Because these facial expressions would be reliably associated with environmental conditions – wide-opened eyes means fast-moving threat; wrinkled nose equals disease – they evolved as social signals, thereby benefitting the perceiver who would know there was a threat, even if they didn’t see it themselves.”

This connects directly with what happens when the lights dim at the cinema. Jeffrey M Zacks is a professor of psychology and radiology at Washington University in St Louis in the US and has written a book called Flicker: Your Brain on Movies, which outlines two principles at work when we watch a film – the Mirror Rule and the Success Rule. “The Mirror Rule says: imitate other humans,” Zacks says.

“If you see somebody smile, smile. If you see somebody cry, cry. The Success Rule says: if you did something that worked last time and you encounter a similar situation, do the same thing this time. The technical term is operant learning or operant conditioning.

“They get your face and your body into a pose associated with an emotion. If you have people whose faces are very sad and they’re 20 foot tall on the screen that tends to make you put your face in a similar pose. The emotion system is built on integrated programmes that includes body posture, and actions and changes in respiration and heart rate and circulation.

“Once you activate part of that programme, it tends to bring along the rest. It really is true that if you walk around smiling you’ll feel better and if you walk around frowning you’ll feel worse.

“If something good is going to happen to a character we identify with we feel good, and if something bad is going to happen we feel bad. The interesting thing is that process happens even though we know it’s not real and we can’t do anything to change the situation.

“This is a big part of what was going on in Inside Out,” Zacks continues. “These people clearly know a heck of a lot about how our emotions and perception and memory work. You know, I didn’t particularly like the film. That’s an opinion that has nothing to do with my expertise, just my experience as a movie-goer, but I still cried through the last 20 minutes – and I’m not a big crier in real life! I think that illustrates wonderfully how effective films are in pushing our emotional buttons.”

Zacks argues there is a cathartic benefit from experiencing a problem and having it resolved as the characters contend with the emotional consequences. “Exploring them yourself is helpful,” he says. “It makes you more empathetic, more emotionally intelligent and healthy.”

So maybe going to the cinema is the secret of being able to live happily ever after.

Inside Out is in cinemas now

Inside Out

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