Stephon Clark, an African-American man, was killed by Sacramento police in his grandmother’s backyard last month, setting off protests and conflict over the police’s actions.

Police initially said they thought Clark was armed. But after the shooting, the officers found no weapon on Clark, only an iPhone. The city’s police chief has been credited with responding quickly to the protests by making the officers’ bodycam footage available, in an attempt to help the public discern what really happened.

But bodycam footage is unlikely to solve every conflict.

Why?

We are psychology scholars whose research focuses on the legal implications of memory errors. Our research, and that of other psychologists and legal scholars, suggests that bodycams may not be the definitive solution to conflicts over police behavior.

Expectations of bodycams

The belief that bodycam footage will both unequivocally show what happened in critical incidents involving police and civilians and thus curb unjustified uses of force is shared by politicians, police departments, civil liberties groups and most of the public. The hope is that bodycam use will help untangle the increasingly conflicted accounts between police and citizens about what happened during a fatal or near-fatal encounter. That hope has prompted local and federal governments to spend millions of dollars ensuring bodycams’ widespread adoption.

Simply put, people trust what they see. So video feels like it should be the cure that will diminish the number of interactions between police and citizens that result in excessive force.

But psychological research suggests there are at least three reasons why bodycam footage will not provide the objectivity people expect.

Bodycam – and human – weaknesses

First is a limitation of the technology: Bodycam footage typically provides a restricted view of an incident. What people can see is often ambiguous, because of the positioning of the camera at chest height on the officer’s uniform. Other limits are created by the camera lens and environmental obstructions. Importantly, people perceive ambiguous stimuli in ways that match their beliefs and preferences, a phenomenon coined “wishful seeing.”

Applied to police footage, this means people’s attitudes toward police influence what they see.

For example, when people watched video of an officer interacting with a citizen, those who were instructed to focus on the officer and who identified with police – that is, they reported thinking they had similar values to police officers or shared a similar background – viewed the officer’s actions as less incriminating.

These people also tended to recommend more lenient punishment for the officer compared to people who focused on the officer but did not identify with police.

So, if you trust police officers and believe you share their values, you see their behavior as more justified.

Second, the fact the officer is not depicted in the bodycam footage means people will focus only on the civilian’s behavior and actions. That can have significant consequences.

For example, in police interrogations, when the camera is directed solely at the suspect, people tend to discount the detective’s role in the scene. Conversely, when they can see the detective, they think about how suggestive or coercive the interrogation tactics may be and tend to be more sympathetic to the suspect.

This means the perspective of the camera literally skews the information people focus on.

Likewise, because bodycams focus on the civilian, people may ignore important information concerning the officer’s role in the encounter. Indeed, some evidence suggests that a bystander’s recording of a police encounter can paint a widely different picture than the bodycam, leading to entirely different conclusions about what the footage shows.

Third, people’s general attitudes toward police don’t just influence how they interpret the police behavior in footage. Those attitudes also influence what they remember seeing in bodycam footage.

We found that people who identified with police (again, people who thought the police were similar to them) were more likely to rely on an officer’s report to make sense of what they saw in bodycam footage.

More specifically, they reported that the civilian in the video was wielding a knife – though no knife was in the video – because the officer said he saw a knife. Those who viewed the video were trying to make sense of the officer’s actions using information they had previously learned, even though it did not fit with the footage.

In essence, the officer’s report served as a source of misleading information, and that is what people remembered seeing.

Unfortunately, research on misinformation effects such as this shows they are notoriously difficult to correct, even when people are warned the information is wrong or are given an explanation for why the error occurred.

Why it matters

All of these factors would pose less of a problem if people had the ability to acknowledge their biases and correct for them.

But, they don’t.

Instead, people believe that what they see and remember is an accurate representation of the world, even if what they see and remember is incorrect.

Interestingly, people acknowledge that biases in other people’s perception and memory will minimize the other people’s ability to be objective observers of police footage.

But people believe they can put their own biases aside. The psychological literature suggests that this belief is inaccurate and may undermine the ability for critical deliberation.

Bodycam footage is enormously valuable because it will likely protect both officers and civilians from false accusations. However, it must be acknowledged that people’s visual and memory biases are more likely to emerge when evidence is ambiguous and people are overconfident in their objectivity.

So bodycam footage is unlikely to be the only solution to improve fraught police–community relations. The justice system is going to have to wrestle further with how to handle these problems.

Deryn Strange receives funding from Charles Koch Foundation.

Kristyn Jones receives funding from Charles Koch Foundation.