Do Head Cameras Always See What You See In A Force Encounter?

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News reports about the head camera currently being tested by selected law enforcement agencies may be raising false expectations regarding the device that could have serious repercussions in some use-of-force investigations, warns the Force Science Institute.

The camera, manufactured by Taser International and a little larger than a Bluetooth earpiece, fits snuggly on an officer’s temple and is commonly perceived as a “third eye” that reliably captures the wearer’s point of view. For example, a recent news story in San Diego, one of the camera’s test cities, was headlined: “What the Officer Sees, the Jury Will See.”

But according to Dr. Bill Lewinski, executive director of the Force Science Institute and a leading researcher on the human dynamics of force encounters, it isn’t that simple, unfortunately.

“There are certain important differences in how human beings process information and how a camera does,” Lewinski told Force Science News. “There is no camera in existence that can record an event exactly as it was perceived by an officer who experienced it.”

In most use-of-force cases, that won’t present a problem. “Head cameras potentially will bring many important benefits to law enforcement, as have in-car videos,” Lewinski says. “In most cases, they’ll be a great help to investigators in reconstructing what an officer faced on the street, they’ll help refresh an officer’s memory so he can give a fuller account of a confrontation, and they’ll help use-of-force reviewers better understand actions of the officer and the suspect.

“But in some cases, there may be differences between what the officer remembers and what the camera recording shows, or the officer may have no recollection of key elements of the scene and the action, or there may be other discrepancies that seem inexplicable or controversial.

“In those cases, if the differences between human perception and camera perception are not understood, the video involved could end up confusing and misleading officers, force reviewers, and the civilian public.”

To minimize that risk, the Force Science Institute proposes that a “Video Advisory” accompany any official viewing of recordings from head cameras, as well as from dash cams, body cams, and other video devices. How such a warning might be phrased will be explored in a moment.

First, the rationale that makes a precautionary statement desirable.

Even with a camera that’s mounted near an officer’s eye and theoretically recording a scene from his or her perspective, certain inescapable differences between human and mechanical processing of information will likely prevent a recording from exactly matching what an officer sees and hears during a critical confrontation such as a shooting, Lewinski explains.

Fundamentally, these differences have to do with field of view, focus of attention, and interpretation.

Selective Perception

The camera, Lewinski points out, is a “neutral, unemotional observer” of a given scene. It has a broad focus, the expanse and detail of which are restricted only by the quality and range of its lens.

In contrast, an officer in a tense, uncertain, and rapidly unfolding situation does not have the same panoramic vision. While the camera indiscriminately captures its broader picture, the officer’s training and experience have taught him from the outset of an encounter to selectively assess a scene or individuals present, hunting, for example, for threat cues.

“He tends to focus on certain kinds of information that interest him, determined by context, and to exclude other information that he considers irrelevant,” Lewinski explains.

“It’s somewhat like asking a carpenter and a surgeon to describe what they each saw when looking at a body on an operating table. The carpenter will see the big picture—with lots of body parts and colors and blood. But the surgeon’s eye and brain will quickly focus in on the bleeding vessel in need of repair, and filter out everything else as unimportant at that moment.

“In the case of the surgeon, his or her training and experience allow for the appropriately quick identification and selective focus on information relevant to an operating room crisis, just as an officer will tend to home in on potential cues to a different kind of threat.

“In contrast to the camera’s inclusiveness, the officer’s brain, like the surgeon’s, is suppressing from cognition what seems unimportant to him. Of millions of bits of information that emanate from a given environment, only a relative trickle will reach the brain’s processing area and only a minute few will be formulated into conscious perceptions upon which judgments will be based.

“Context influences meaning. A camera does not have the officer’s experience so it does not know or record how he is interpreting what he is seeing.”

Narrowing Focus

The more imminent the life threat, the more the officer’s vision involuntarily narrows to isolate the threat and see it in greater detail,” Lewinski says. “He focuses and sees within a range of only about 3 to 5 degrees, a mere fraction of the breadth that the camera is recording. Comparing what a camera captures to what actually registers in an officer’s brain doesn’t give a true rendering of what the officer actually perceived in the stressful moment.

“Think of what the camera shows as ‘the big screen’ in a movie theater. Under stress the officer is only able to perceive the part of the movie that you might see if you were watching it through a paper towel tube. There is no way for the camera to isolate the limited part of the scene that perhaps captured the officer’s entire field of attention.

“To a reviewer, that part might appear as a small detail. But to the involved officer whose life was on the line, it might have seemed to be the whole show. When the recording is played later, we don’t really know just from watching it what part of it the officer was actually focused on.”

We can be highly confident, however, that a phenomenon called “inattentional blindness” likely came into play in any major force encounter. That means simply that the officer did not—could not—see things he was not concentrating on at the time but which may later turn out to be quite important in the larger context of the encounter.

Says Lewinski: “Someone who doesn’t understand the human dynamics involved may conclude that the officer is lying when he says he wasn’t aware of persons or actions that appear plainly in the camera’s recording and seem to have been in his field of view.”

Other factors

In addition to the critical issue of selective focus, there are light and depth considerations. “In low-light situations especially, the human eye is likely to perceive things differently from a camera lens, and a camera’s 2-D recording is much different than the eyes’ 3-D capability, particularly when it comes to calculating depth and distances,” Lewinski says. “In 3-D, something coming directly at you, such as a speeding car, seems significantly different to you than it does in a flat, 2-D image.”

And there is this indisputable fact: “After an incident is over, hours can be spent playing a video recording over and over again, analyzing what happened and picking out things an officer ‘should’ have been able to see,” Lewinski says. “But as an encounter is unfolding, an officer gets only one run-through—a narrow, fragmented view that may last only milliseconds but on which he must make decisions that can have life-or-death consequences.”

Bottom Line

All things considered, this is the bottom line Lewinski believes is essential to recognize:

“A camera will never represent precisely an officer’s view of a scene or what an officer was thinking at any given instant or how he was interpreting what he was seeing, even if the camera is right beside the officer’s eye. Ideally, a camera may help us understand why an officer acted as he did, but in some cases it may be only a start.

“Ultimately, we need to judge uses of force from the viewpoint of the officers involved rather than from the viewpoint of a camera. Otherwise, an officer reviewing a recording may be confused by discrepancies between what he remembers and what the camera shows, and persons judging the incident may inappropriately hold him accountable for actions and statements that don’t appear to jibe with the filmed record.”

Recommended Advisory

With that in mind, the Force Science Institute recommends that an advisory be delivered before an officer views any video recording of an incident he was involved in or before persons responsible for judging the officer’s actions see it. Here is suggested language for this caution, formulated with the help of attorney John Hoag, who has represented scores of officers in OIS investigations and who serves on the national advisory board of the Institute:


You are about to view a camera recording of a use-of-force event. Understand that while this recording depicts visual information from the scene, the human eye and brain are highly likely to perceive some things in stressful situations differently than a camera records them, so this photographic record may not reflect how the involved officer actually perceived the event.

The recording may depict things that the officer did not see or hear. The officer may have seen or heard things that were not recorded by the camera. Depending on the speed of the camera, some action elements may not have been recorded or may have happened faster than the officer could perceive and absorb them. The camera has captured a 2-dimensional image, which may be different from an officer’s 3-dimensional observations. Lighting and angles may also have contributed to different perceptions. And, of course, the camera did not view the scene with the officer’s unique experience and training.

Hopefully, this recording will enhance your understanding of the incident. Keep in mind, though, that these video images are only one piece of evidence to be considered in reconstructing and evaluating the totality of the circumstances. Some elements may require further exploration and explanation before the investigation is concluded.

Lewinski notes: “The purpose of the Advisory is not to challenge the integrity of state-of-the-art recording equipment, but to remind all parties that it necessarily has intrinsic limitations. This advisory is offered as a useful tool in promoting thorough and impartial investigations of uses of force.

“Properly framed, camera recordings can be great memory refreshers for involved officers and offer valuable insights for reviewers. The key lies in understanding that they are not likely to be the be-all and end-all for explaining every incident.”

The considerations touched on in this report are explored in greater detail during FSI’s certification course in Force Science Analysis.

Our thanks to Chris Lawrence, a member of the Force Science Institute’s national advisory board, for suggesting this article and to Atty. William Everett, also a national advisor, for his constructive review.

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