Ever watch a movie and notice your heart race or your emotions swell even though you know it's all fake?
Scientists studying the brain have begun to find out how films create such visceral responses in us.
It turns out there are complex processes happening in multiple areas of the brain that allow us to get swept up in a movie, according to Washington University psychology professor Jeff Zacks.
"You know there is nothing up there on the screen that can touch you or hurt you or pull you out of your chair but we react as if they can," Zacks said.
He recently wrote a book on the topic called "Flicker: Your Brain on Movies."
As an example, he likes to reference the fight scene at the start of "Rocky II," where Sylvester Stallone as Rocky is in an all out brawl with Carl Weathers as Apollo Creed.
At times, the camera's perspective hovers just over the boxer's shoulders as punches fly.
"Just try not to flinch when you watch that," Zacks said. "Basically you are getting punched in the face on the screen."
Zacks says that flinch response is actually the result of hundreds of thousands of years of evolution.
Our ancient ancestors developed reflexes to dodge oncoming objects.
So today, even though we know we’re safe watching Rocky on the screen, we still might flinch involuntarily.
"And it’s a good thing that you do!" Zacks said. "It’s because our ancestors flinched in the right places that they passed on their genes and we are around to watch those movies."
There are also cells in our brain called mirror neurons. They are active when we learn new motor skills, but research shows they also fire up when we watch other’s doing similar actions.
Zacks thinks these may play a part in our response to seeing action on the big screen.
They may also help us relate to emotions, so that when we see a smile in a movie we are more likely to want to smile ourselves.
For moviegoer Corinn Jackson, it was the tension in the latest "Hunger Games" film that left her unsettled.
"I'm still stressed out," she said after leaving a recent showing of "The Hunger Games: Mockingjay, Part 1."
"I kept getting chills, ... and I kept jumping, so even though it was a flat screen, the sounds were freaking me out."
Zacks said this kind of deep physical response is normal since the brain processes most of the stimuli from a movie the way it would process real life.
The brain has to actually stop itself from taking a movie too seriously.
"You have to shut down the stuff that’s going to keep you acting like it’s happening in real life."
Zacks said an area known as the prefrontal cortex helps with that. It’s a region of the brain associated with self-control.
Patients with damage to this area are more likely to respond to movies as if they are real, he noted.
Kids have a similar problem, since their prefrontal cortex is still developing, he explained. That's why kids sometimes talk back to movies or jump our of their seats and hide during scary scenes.
These are just some of the insights Zacks and others are learning from studying how we watch movies.
The Academy of Motion Pictures Arts and Science recently hosted an event focused on this emerging field. Researchers talked about how movies can help us understand things like eye movement and attention.
"This is one of the next stages in brain science," said UCLA cognitive neuroscientist Ladan Shams.
Shams doesn't study movies herself, but she is interested in many of the same questions of perception that researchers like Zacks are tackling.
She said movies are great for scientific research because subjects can watch them while sitting in a brain-imaging machine like an fMRI.
That means neuroscientists can see what areas of the brain a movie is activating.
She added movies are much closer to real life than the simple shapes and sounds used in earlier neuroimaging studies, but said there are limitations to this kind of research.
"[Movies are] a passive experience, somebody sits and watches something," she said. "The real world is an active experience, we interact with our environment."
Still, Shams thinks that by studying how movies trick our senses, we might learn new ways to help people with sensory disorders, like autism and dyslexia.
Jeff Zacks says there’s another reason to study the science of film.
"People spend a lot of time and emotional energy on stories, on experiencing stories and understanding how that works is therefore a really important problem."
After all, it could be argued that watching and relating to the struggles of others is part of what makes us human. Zacks says that’s worth examining too.
So, as movies continue to put our stories on the silver screen, scientists will continue to put movies under the microscope.