R E S E A R C H I N B R I E F

The IACP Research Advisory Committee is proud to offer monthly the Monthly Research in Brief column. This column features evidence based research summaries that highlight actionable recommendations for Police Chief magazine readers to consider within their own agencies. The goal of the column is to feature research that is innovative, credible, and relevant to a diverse law enforcement audience. Efficacy of Police Body Cameras for Evidentiary Purposes: Fact or Fallacy?

The Police Chief, vol. LXXXII, no. 5, May 2015. Copyright held by the International Association of Chiefs of Police, 515 North Washington Street, Alexandria, VA 22314 USA.

Craig E. Geis, MA, MBA, footage in use‐of‐force (UOF) or information can be extracted at Lieutenant Colonel (ret.), U.S. officer‐involved shooting (OIS) a brief glance without eye or Army, and David M. Blake, investigations. The ramifications head movements, is 55 to 60 MSc, California Training for not understanding the degrees under optimal, normal Institute differences include stress.2 inappropriate or unfair Within its FOV, the camera disciplinary actions, increased can provide HD quality playback Police body cameras have liability, and potential wrongful of everything within its become a hot topic in both law incarceration. viewable angles, but the enforcement and the media. physiology of the human eye Studies and reviews are already Physiology of the Human Visual ensures a similar HD version of showing some positive results Experience acuity only within the 1–2 of deploying cameras, but there Research to shed light on the degree angle of the fovea is a lack of knowledge and difference between the visual centralis, with vision sharply education on the differences experience of humans and decreasing toward the between the mechanisms cameras first looked at the field periphery.3 The differences here involved in of view (FOV) of body cameras ensure the camera will “see” and compared them to human and record more of an event in human sight and camera visual capabilities. The body much higher quality than a “sight.”1 Human eyes and cameras reviewed in this study human is capable of seeing. camera lenses see, process, and provide anywhere from a 95 to The mechanical differences recall information differently. It a 170 degree FOV. The normal also include the cognitive is important to understand the useful field of view in human concept of human “attention.” differences before using camera vision, the area from which While a camera lens is a stable mechanism, a person’s eye is in imperative to understand the remember some aspects of the constant motion and scans the difference between the visual encounter that a camera would environment about three times acuity and perception of a capture. per second. These rapid eye human being. Visual acuity is A camera cannot recreate movements are called “visual the clarity of vision, the ability what a human under acute saccades.”4 Saccades provide to detect and see fine details. stress sees, hears, and feels, nor near foveal (precise) vision of can it incorporate the the environment, but must Foveal Vision perspective derived from fixate on an object for a For a demonstration of foveal previous training and minimum of 160–200 vision, make your left hand experience or provide context milliseconds in order for the into a fist with the thumb to a UOF or OIS event. brain to perceive and store the extended and hold it at arm’s Cameras provide a information. This form of length an inch in front of this reenactment of events from a sampling is called “visual text. Close your right eye and mechanical view, unaffected by attention.” Because humans focus the left eye’s vision on stress, and produce images on visually attend to environmental the left thumbnail. With the film in a linear fashion for aspects based only upon need, left eye remaining fixed on replay. Human memory, they may not perceive or attend your left thumb, you should however, is a weave of events to other aspects, even if they notice the words immediately and experiences, stored in are within the eye’s visual field. to the left and right are different areas of the brain and Additionally, the subconscious significantly blurry. tenuously attached to one brain rejects significant another. The human body amounts of incoming Perception involves the process releases cortisol during high‐ bandwidth, sending only a small of not only detecting an object, stress situations, which has fraction of its data on to the but also comprehending the severe effects upon memory, conscious brain. While the object’s significance. A camera blocking pathways and ensuring camera has “global attention” may have perfect visual acuity, a memory is stored in a and will record all the data from but has no perception. Only the fractionated manner or, in some its FOV on film to be viewed human brain can perceive and cases, never stored at all. The later, human physiology is not process the significance of the camera transfers its view into recording the same level of data incoming data, which means digital media with no cortisol to be stored in memory. Hence, that only humans can impediment.6 An officer who human perception and memory experience the subsequent does not remember the event of an event can be dramatically stress and arousal caused by clearly or who recounts it different than what is recorded that data. differently than what was seen by the camera. This difference UOF and OIS incidents are by the camera may fight an increases substantially when chaotic and violent, typically uphill battle against those who the stress and arousal of an UOF causing high levels of stress and are uninformed. or OIS event is a factor. activating the limbic system’s Body cameras are the wave of fight or flight mechanisms, the future in law enforcement The Effects of Stress and which, in turn, triggers the and are already showing their Arousal on Vision and Memory release of hormones and many positive contributions. As The U.S. Supreme Court’s neurotransmitters throughout with all new technologies, there Graham v. Connor ruling the body. Stress and arousal will be growing pains and provides that evidence of causes an individual’s useful learning curves. However, in the reasonableness must include field of view to narrow most severe of cases, when the officer’s perception of the (“peripheral narrowing”). Under careers are on the line and event during “tense, uncertain, extreme stress, a person’s field hefty civil penalties wait on the and rapidly evolving events” of view can narrow to one half sidelines, education on these and not through “20/20 of a degree. Peripheral new devices with a sense of hindsight.”5 When considering narrowing and selective urgency that mimics their rapid the 20/20 hindsight provided by attention will cause the deployment is critical. The camera evidence, it is individual to not perceive or ramifications of not doing so could be extensive, affecting Notes: 3Melchor J. Antuñano, Pilot Vision, both individual officers and the Medical Facts for Pilots (FAA Civil 1Tony Farrar, Self‐Awareness to Being Aerospace Medical Institute, 2002), entities that employ them. Watched and Socially‐Desirable http://www.faa.gov/pilots/safety/pilots Behavior: A Field Experiment on the afetybrochures/media/pilot_vision.pdf Recommendations Effect of Body‐Worn Cameras on Police (accessed April 1, 2015). “Cones” are a  Law enforcement (at all Use‐of‐Force (Police Foundation, March type of light‐sensitive cells used for day 2013), or high‐intensity light vision. They are levels) should be http://www.policefoundation.org/sites/ involved with central vision to detect educated in the science of g/files/g798246/f/201303/The%20Effec detail, perceive color, and identify far‐ human behavior and t% 20of%20Body‐ away objects. The central area of the human performance. Worn%20Cameras%20on%20Police%20 retina known as the macula is about 4.5 Use‐of‐Force.pdf (accessed April 1, mm in diameter and has a higher Education is a proven 2015); Allyson Roy, “On‐Officer Video percentage of cones, and the exact method to reduce Cameras: Examining the Effects of Police center of the macula has a very small departmental liability and Department Policy and Assignment on depression called the fovea centralis to save officers from Camera Use and Activation” (master’s that contains only cones. thesis, Arizona State University, 2014), criminal prosecution or http://repository.asu.edu/attachments/ 4John M. Henderson, “Human Gaze unwarranted discipline. 134979/content/Roy_asu_0010N_1380 Control During Real‐World Scene  Law enforcement 3.pdf (accessed April 1, 2015); Michael Perception,” TRENDS in Cognitive D. White, Police Officer Body‐Worn Sciences 7, no. 11 (November 2003), agencies should test body Cameras: Assessing the Evidence http://cvcl.mit.edu/SUNSeminar/Hende cameras in reality‐based (Washington, D.C.: Office of Community rson_03.pdf (accessed April 1, 2015). training environments Oriented Policing Services, 2014), 5 and compare officers’ https://ojpdiagnosticcenter.org/sites/de Graham v. Connor, 490 U.S. 386 fault/files/spotlight/download/Police% (1989). memories to after‐action 20Officer%20Body‐ reviews of video footage Worn%20Cameras.pdf (accessed April 1, 6Washington University School of from the training. 2015). Medicine, “High Stress Hormone Levels  Law enforcement should Impair Memory,” ScienceDaily, 2Karlene K. Ball, Virginia G. Wadley, http://www.sciencedaily.com/releases/ engage prosecutors, and Jerri D. Edwards, “Advances in 1999/06/990617072302.htm (accessed defense attorneys, and Technology Used to Assess and Retrain April 1, 2015). the judiciary in Older Drivers,” Gerontechnology 1, no. 4 conversations regarding (2002), 251 –261. For additional articles and courses

the camera versus human available go to www.cti‐home.com issues. or contact California Training  Law enforcement should Institute at 707‐968‐5109, info@cti‐

engage their communities home.com

in similar discussions regarding camera versus human issues. ♦