December 10, 2019

Video evidence – surveillance cameras, body-worn cameras used by police, interrogation room cameras – are much better than lay descriptions of events.  As long as they are preserved and not tampered with, they provide certain indisputable evidence – who was there, who said what (and in what tone of voice), and certain observable consequences (e.g. a shooting).  But video has its limits, particularly when linked to cognitive biases.

What are the biases?  They may arise from where the camera is placed, which creates perspective; or from the life experiences of the observer, which impact interpretation.  This NOTE “examines recent developments in the research of situational video evidence biases. Part I examines the current and growing body of psychological research into the various situational biases that can affect the reliability of video evidence and the gaps in this research that require further attention from researchers and legal academics.”

Those addressing video evidence must be aware of two types of bias.  “Dispositional biases are those motivated by culture, beliefs, values, and group commitments (conscious or unconscious) of the viewer.  Situational biases result from the interaction between contextual factors and subconscious cognitive processes.”  An example of situational bias is the camera’s perspective – is it looking at the face of the suspect or the face of the interrogator?   The change in perspective has been shown to impact how observers feel about whether the resulting confession is voluntary.  Dispositional bias may be a result of the viewer’s race or political beliefs.

Another concern referenced here is that of how the video is presented.  The article discusses research on how a slow motion display may affect perceptions of the intentionality of the actor.

So before you rely on or seek to discount video evidence, read a little and reconfigure your biases.  This article is a terrific compendium of information.