Although many in the U.S., including President Barack Obama, are currently calling on police forces to don body cameras to diminish excessive use of force, no scientific studies have proved the cameras' effectiveness.

Now, however, researchers from the University of Cambridge's Institute of Criminology, are publishing the first scientific study of a California police department's use of body cameras, with results showing that not only do the cameras protect the public from the police, but the cameras also protect the police from the public.

In 2012, researchers gave body cameras to police officers in Rialto, California. The officers wore the cameras for a year. During that year, the researchers saw a significant drop in use-of-force by police, falling by 59 percent. However, there was an even more significant drop in violence against officers, which fell by 87 percent from the previous year.

This suggests that cameras worn by police officers don't just protect people from excessive use of force by police, but that the cameras also protect police from abusive behavior by the public.

The idea of body-worn cameras is that they create "self-awareness," not just for the police but for those they interact with. The police must make a statement that every interaction is recorded when dealing with the public. Researchers believe this makes all participants modify their behavior as they know there is a "third party" watching their every move and that the camera footage could be used in court should unacceptable behavior occur.

"Police subcultures of illegitimate force responses are likely to be affected by the cameras, because misconduct cannot go undetected - an external set of behavioural norms is being applied and enforced through the cameras," says Dr. Barak Ariel, from Cambridge University. "Police-public encounters become more transparent and the curtain of silence that protects misconduct can more easily be unveiled, which makes misconduct less likely."

Still, researchers suggest that we need more studies before we arm all police forces in the country with cameras. Although the cameras are relatively inexpensive and save money by preventing litigation, their footage requires a lot of data storage, which ultimately, could be expensive.

"Body-worn-video has the potential to improve police legitimacy and enhance democracy, not least by calming situations on the front line of policing to prevent the pain and damage caused by unnecessary escalations of volatile situations," says Ariel. "But there are substantial effects of body-worn-video that can potentially offset the benefits which future research needs to explore."