Watching a biopic about a wrongly convicted man boosted empathy towards incarcerated people and increased support for reforms to the US criminal justice system, according to a new scientific study.

Storytelling is about changing minds, and film is no different. Since the first moving pictures in the 1890s, filmmakers have used the tricks of cinema to shift people's perceptions and moral compasses.

Now, scientists in the United States have measured how watching a film changes people's ability to understand emotions and their moral positions on the criminal justice system.

The new study, published October 21 in the journal PNAS, found that watching a docudrama about efforts to free a wrongly convicted man on death row increased empathy towards incarcerated people and support for reforms to the US criminal justice system.

"[Our study] suggests the film made participants either more willing or more capable of understanding another human being despite societal stigmas against them. This is more than a fleeting feeling, but a skill," said Marianne Reddan, a cognitive scientist at Stanford University, US, who co-led the study.

"It tells us that exposing people to the personal experiences of people who live very different lives from their own is essential for the development of healthy communities and healthy political structures."

'Just Mercy' docudrama increases empathy

In 1986, Walter McMillian, a Black 45-year-old logger living in Alabama, was arrested for murder. McMillian was innocent — he was at a family gathering when the crime occurred — but was convicted based on false eyewitness testimony. He spent six years on death row before a court overturned his conviction.

This true story was made into a biopic called "Just Mercy," released in 2019 and starring Oscar winner Jamie Foxx as McMillan.

After watching "Just Mercy," participants of the study had increased empathy test scores toward men who had been in jail. These effects were found in politically left- and right-leaning participants alike.

"This study measured more than the feeling of empathy, but also participants' capacity to understand the emotions of a formerly incarcerated person they have never met before," said Reddan.

Watching the film also increased support for criminal justice reform, such as the idea of using tax money to fund educational programs in prisons or raising opposition to the death penalty.

The researchers also found that people who watched "Just Mercy" were 7.7% more likely than participants in the control group to sign a petition supporting criminal justice reform.

"This study underscores the influence of audiovisual content in shaping public opinion and potentially motivating collective action. 'Just Mercy' shifted people's perceptions, but also their behaviors," said Jose Cañas Bajo, a researcher in cognitive science and film studies at the University of Jyvaskyla in Finland, who was not involved in the study.

Film, emotion, and polarization

Cañas Bajo said the novelty of this study lies in the method of quantifying how films can change viewers' perceptions and behaviors, especially how "a film like 'Just Mercy' can function as a call to action."

But the idea that a film can change minds is not new. "Filmmakers are like magicians. They have been researching how to influence viewers' perceptions and emotions with editing tricks since the earliest days of film," he said.

Alfred Hitchcock demonstrated this effect by filming a scene of a woman with a child, which then cuts to a man smiling, seemingly sympathetically. But if the scene of a woman and her child is replaced by a woman in her bikini, Hitchcock says, the man's smile appears lecherous.

Cañas Bajo explained that filmmakers often play with the knowledge that film is a safe space where viewers can experience emotions they don't typically feel. Have you ever felt empathy towards real killers in a TV show, like the Menendez brothers in Netflix's crime drama Monster?

It's for this reason that filmmakers have responsibilities towards their viewers when telling stories, Cañas Bajo said.

In this study, the "Just Mercy" filmmakers used their skills to influence viewers' empathy towards a man imprisoned for a murder he never committed. The film was used as a tool for progressive social change in the criminal justice system.

But filmmakers can use the same tricks to create antipathy, the opposite of empathy, toward people they frame in a bad light. Propaganda films have long been used to dehumanize people and justify violence or war or to push false narratives and pseudoscience.

"Some crime docufilms provoke antipathy towards the perpetrators, which can fuel demands for more punitive measures, including capital punishment," said Cañas Bajo.

How long does empathy last?

An open question from this study is how long feelings of empathy last for after watching a film. Is watching one film enough to create lasting changes to your political or moral views?

Reddan said her team is currently conducting a new study about the durability of these effects over a three-month time period.

"Preliminary evidence indicates some of these effects persist for at least three months. We are also currently collecting neuroimaging data of this paradigm to understand how the film influences empathetic processing at the level of the brain," Reddan said.

But the difficulty is disentangling the effect of one movie on its own, Cañas Bajo said.

When we watch a film, we are always comparing it to our own memories and other films we may have seen. Films don't have to be made by the same person to be emotionally linked with one another. That happens in the viewers' heads.

Reddan said this is why we should be mindful of the type of media we consume.

"The media that we largely consume for entertainment has a significant impact on how we relate to one another," she said.