Why inaccuracies in movies can contaminate memories

By Jeffrey M. Zacks, Published The Straits Times, 19 Feb 2015

New York - This year's Oscar nominees for Best Picture include four films based on true stories: American Sniper (about sharpshooter Chris Kyle), The Imitation Game (about mathematician Alan Turing), Selma (about the passage of the Voting Rights Act in 1965) and The Theory Of Everything (about physicist Stephen Hawking).

Each film has been criticised for factual inaccuracy. Doesn't Selma ignore Lyndon B. Johnson's dedication to black voting rights? Doesn't The Imitation Game misrepresent the nature of Turing's work, just as The Theory Of Everything does Hawking's? Doesn't American Sniper sanitise the military conflicts it purports to depict?

You might think: Does it really matter? Can't we keep the film world separate from the real world?

Unfortunately, the answer is no. Studies show that if you watch a film - even one concerning historical events about which you are informed - your beliefs may be reshaped by "facts" that are not factual.

In a study published in the Psychological Science journal in 2009, researchers had college students read historical essays and then watch clips from films containing inaccurate information. Despite being warned that the films might contain factual distortions, the students produced about a third of the fake facts from the movies on a subsequent test.

In a study published in Applied Cognitive Psychology in 2012, researchers repeated the experiment and tried to eliminate the "misinformation effect" by explicitly asking the students to monitor the clips for inaccuracies.

It didn't work. The more engaged the students were by the clips, the more their memories were contaminated.

Why do we have such a hard time sorting film "facts" from real facts? One suggestion is that our minds are well equipped to remember things that we see or hear - but not to remember the source of those memories.

Consider the following evolutionary story. As our distant ancestors became increasingly able to communicate facts to one another via language and to store them in their memories, this helped them survive. If a hunter approached a watering hole, being able to remember that there had been a lion attack at that hole could be a lifesaver.

But retrieving the source of the memory was less critical. As a result, our brain's systems for source memory are not robust and are prone to failure.

This story is speculative, but it is consistent with what we know about source memory. Cognitively, source memory develops relatively late in children; and neurologically, it depends selectively on the prefrontal cortex, a region of the brain that is also late to mature.

Source memory is highly sensitive to the vicissitudes of ageing, injury and disease. Patients with damage to the prefrontal cortex exhibit failures of source memory that exaggerate the everyday errors we all make.

One research subject who had suffered a lesion to his prefrontal cortex believed that a particular building was being used for sinister purposes; only later did it emerge that his paranoid interpretation of the building was a result of a spy film he had watched 40 years before.

The weakness of source memory leaves us, to some degree, at the mercy of inaccurate films. Is there anything we can do?

The research described did reveal one technique that helps: Having the misinformation explicitly pointed out and corrected at the time it was encountered substantially reduced its influence.

But actually implementing this strategy - creating fact-checking commentary tracks that play during movies or always taking a historian to the theatre with you - could be a challenge.

New York Times