Expecting
too much of a single camera mounted on a police officer
spells disaster
By:
Force Science
The idea is building that once every cop is equipped
with a body camera, the controversy will be taken out of
police shootings and other uses of force because “what
really happened” will be captured on video for all to
see.
Well, to borrow the title from an old Gershwin tune, “It
Ain’t Necessarily So.”
There’s no doubt that body cameras—like dash cams, cell
phone cams, and surveillance cams—can provide a unique
perspective on police encounters and, in most cases, are
likely to help officers. But like those other devices, a
camera mounted on your uniform or on your head has
limitations that need to be understood and considered
when evaluating the images they record.
“Rushing to condemn an officer for inappropriate
behavior based solely on body-camera evidence can be a
dicey proposition,” cautions Dr. Bill Lewinski,
executive director of the Force Science Institute.
“Certainly, a camera can provide more information
about what happened on the street. But it can’t
necessarily provide all the information needed to
make a fair and impartial final judgment. There still
may be influential human factors involved, apart from
what the camera sees.”
In a recent conversation with Force Science News,
Lewinski enumerated 10 limitations that are important to
keep in mind regarding body-camera evidence (and, for
the most part, recordings from other cameras as well) if
you are an investigator, a police attorney, a force
reviewer, or an involved officer. This information may
also be helpful in efforts to educate your community.
1. A camera doesn’t follow your eyes or see as they see.
At the current level of development, a body camera is
not an eye-tracker like FSI has used in some of
its studies of officer attention. That complex apparatus
can follow the movement of your eyes and superimpose on
video small red circles that mark precisely where you
are looking from one microsecond to the next.
“A body camera photographs a broad scene but it can’t
document where within that scene you are looking at any
given instant,” Lewinski says. “If you glance away from
where the camera is concentrating, you may not see
action within the camera frame that appears to be
occurring ‘right before your eyes.’
“Likewise, the camera can’t acknowledge physiological
and psychological phenomena that you may experience
under high stress. As a survival mechanism, your brain
may suppress some incoming visual images that seem
unimportant in a life-threatening situation so you can
completely focus very narrowly on the threat. You won’t
be aware of what your brain is screening out.
“Your brain may also play visual tricks on you that the
camera can’t match. If a suspect is driving a vehicle
toward you, for example, it will seem to be closer,
larger, and faster than it really is because of a
phenomenon called ‘looming.’ Camera footage may not
convey the same sense of threat that you experienced.
“In short, there can be a huge disconnect between your
field of view and your visual perception and the
camera’s. Later, someone reviewing what’s caught on
camera and judging your actions could have a profoundly
different sense of what happened than you had at the
time it was occurring.”
2. Some important danger cues can’t be recorded.
“Tactile cues that are often important to officers in
deciding to use force are difficult for cameras to
capture,” Lewinski says. “Resistive tension is a prime
example.
“You can usually tell when you touch a suspect whether
he or she is going to resist. You may quickly apply
force as a preemptive measure, but on camera it may look
like you made an unprovoked attack, because the sensory
cue you felt doesn’t record visually.”
And, of course, the camera can’t record the history and
experience you bring to an encounter. “Suspect behavior
that may appear innocuous on film to a naïve civilian
can convey the risk of mortal danger to you as a
streetwise officer,” Lewinski says. “For instance, an
assaultive subject who brings his hands up may look to a
civilian like he’s surrendering, but to you, based on
past experience, that can be a very intimidating and
combative movement, signaling his preparation for a
fighting attack. The camera just captures the action,
not your interpretation.”
3. Camera speed differs from the speed of life.
Because body cameras record at much higher speeds than
typical convenience store or correctional facility
security cameras, it’s less likely that important
details will be lost in the millisecond gaps between
frames, as sometimes happens with those cruder devices.
“But it’s still theoretically possible that something as
brief as a muzzle flash or the glint of a knife blade
that may become a factor in a use-of-force case could
still fail to be recorded,” Lewinski says.
Of greater consequence, he believes, is the body
camera’s depiction of action and reaction times.
“Because of the reactionary curve, an officer can be
half a second or more behind the action as it unfolds on
the screen,” Lewinski explains. “Whether he’s shooting
or stopping shooting, his recognition, decision-making,
and physical activation all take time—but obviously
can’t be shown on camera.
“People who don’t understand this reactionary process
won’t factor it in when viewing the footage. They’ll
think the officer is keeping pace with the speed of the
action as the camera records it. So without
knowledgeable input, they aren’t likely to understand
how an officer can unintentionally end up placing rounds
in a suspect’s back or firing additional shots after a
threat has ended.”
4. A camera may see better than you do in low light.
“The high-tech imaging of body cameras allows them to
record with clarity in many low-light settings,”
Lewinski says. “When footage is screened later, it may
actually be possible to see elements of the scene in
sharper detail than you could at the time the camera was
activated.
“If you are receiving less visual information than the
camera is recording under time-pressured circumstances,
you are going to be more dependent on context and
movement in assessing and reacting to potential threats.
In dim light, a suspect’s posturing will likely mean
more to you immediately than some object he’s holding.
When footage is reviewed later, it may be evident that
the object in his hand was a cell phone, say, rather
than a gun. If you’re expected to have seen that as
clearly as the camera did, your reaction might seem
highly inappropriate.”
On the other hand, he notes, cameras do not always deal
well with lighting transitions. “Going suddenly from
bright to dim light or vice versa, a camera may briefly
blank out images altogether,” he says.
5. Your body may block the view.
“How much of a scene a camera captures is highly
dependent on where it’s positioned and where the action
takes place,” Lewinski notes. “Depending on location and
angle, a picture may be blocked by your own body parts,
from your nose to your hands.
“If you’re firing a gun or a Taser, for example, a
camera on your chest may not record much more than your
extended arms and hands. Or just blading your stance may
obscure the camera’s view. Critical moments within a
scenario that you can see may be missed entirely by your
body cam because of these dynamics, ultimately masking
what a reviewer may need to see to make a fair
judgment.”
6. A camera only records in 2-D.
Because cameras don’t record depth of field—the third
dimension that’s perceived by the human eye—accurately
judging distances on their footage can be difficult.
“Depending on the lens involved, cameras may compress
distances between objects or make them appear closer
than they really are,” Lewinski says. “Without a proper
sense of distance, a reviewer may misinterpret the level
of threat an officer was facing.”
In the Force Science Certification Course, he
critiques several camera images in which distance
distortion became problematic. In one, an officer’s use
of force seemed inappropriate because the suspect
appears to be too far away to pose an immediate threat.
In another, an officer appears to strike a suspect’s
head with a flashlight when, in fact, the blow was
directed at a hand and never touched the head.
“There are technical means for determining distances on
2-D recordings,” Lewinski says, “but these are not
commonly known or accessed by most investigators.”
7. The absence of sophisticated time-stamping may prove
critical.
The time-stamping that is automatically imposed on
camera footage is a gross number, generally measuring
the action minute by minute. “In some high-profile,
controversial shooting cases that is not sophisticated
enough,” Lewinski says. “To fully analyze and
explain an officer’s perceptions, reaction time,
judgment, and decision-making it may be critical to
break the action down to units of one-hundredths of a
second or even less.
“There are post-production computer programs that can
electronically encode footage to those specifications,
and the Force Science Institute strongly
recommends that these be employed. When reviewers see
precisely how quickly suspects can move and how fast the
various elements of a use-of-force event unfold, it can
radically change their perception of what happened and
the pressure involved officers were under to act.”
8. One camera may not be enough.
“The more cameras there are recording a force event, the
more opportunities there are likely to be to clarify
uncertainties,” Lewinski says. “The angle, the ambient
lighting, and other elements will almost certainly vary
from one officer’s perspective to another’s, and syncing
the footage up will provide broader information for
understanding the dynamics of what happened. What looks
like an egregious action from one angle may seem
perfectly justified from another.
“Think of the analysis of plays in a football game. In
resolving close calls, referees want to view the action
from as many cameras as possible to fully understand
what they’re seeing. Ideally, officers deserve the same
consideration. The problem is that many times there is
only one camera involved, compared to a dozen that may
be consulted in a sporting event, and in that case the
limitations must be kept even firmer in mind.
9. A camera encourages second-guessing.
“According to the U. S. Supreme Court in Graham v.
Connor, an officer’s decisions in tense, uncertain,
and rapidly evolving situations are not to be judged
with the ‘20/20 vision of hindsight,’ ” Lewinski notes.
“But in the real-world aftermath of a shooting, camera
footage provides an almost irresistible temptation for
reviewers to play the coulda-shoulda game.
“Under calm and comfortable conditions, they can
infinitely replay the action, scrutinize it for
hard-to-see detail, slow it down, freeze it. The officer
had to assess what he was experiencing while it was
happening and under the stress of his life potentially
being on the line. That disparity can lead to far
different conclusions.
“As part of the incident investigation, we recommend
that an officer be permitted to see what his body camera
and other cameras recorded. He should be cautioned,
however, to regard the footage only as informational. He
should not allow it to supplant his first-hand memory of
the incident. Justification for a shooting or other use
of force will come from what an officer reasonably
perceived, not necessarily from what a camera saw.”
[For more details about FSI’s position on whether
officers should be allowed to view video of their
incidents, see Force Science News #114 (1/17/09).
You will find online it at:
www.forcescience.org/fsnews/114.html]
10. A camera can never replace a thorough investigation.
When officers oppose wearing cameras, civilians
sometimes assume they fear “transparency.” But more
often, Lewinski believes, they are concerned that camera
recordings will be given undue, if not exclusive, weight
in judging their actions.
“A camera’s recording should never be regarded solely
as the Truth about a controversial incident,”
Lewinski declares. “It needs to be weighed and tested
against witness testimony, forensics, the involved
officer’s statement, and other elements of a fair,
thorough, and impartial investigation that takes human
factors into consideration.
“This is in no way intended to belittle the merits of
body cameras. Early testing has shown that they tend to
reduce the frequency of force encounters as well as
complaints against officers.
“But a well-known police defense attorney is not far
wrong when he calls cameras ‘the best evidence and the
worst evidence.’ The limitations of body cams and others
need to be fully understood and evaluated to maximize
their effectiveness and to assure that they are not
regarded as infallible ‘magic bullets’ by people who do
not fully grasp the realities of force dynamics.”
Our thanks to Parris Ward, director and litigation
graphics consultant with Biodynamics Engineering, Inc.,
for his help in facilitating this report.
For more information on the work of the Force Science
Institute, visit www.forcescience.org. To reach the
Force Science News editorial staff please e-mail:
editor@forcescience.org.
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