Wednesday, April 25, 2007

Violent Encounters, Cops, and the Frailty of Human Memory

We recently stumbled across a joint DOJ/FBI publication called Violent Encounters: A Study of Felonious Assaults on our Nation's Law Enforcement Officers (Aug. 2006), which purports to "offer insights that may help to improve safety-training techniques." One source of insight happens to be the same social science research on which reform advocates rely to show the fallibility of human memory in the eyewitness context.

Chapter 5 of this training manual is titled "Perception -- Its Role in the Violent Encounter." The chapter examines a collection actual violent encounters undergone by police officers, and chronicles a laundry list of cognitive errors that were associated with the events in the officers' memories. The chapter reads like a greatest-hits of factors tending to reduce the reliability of eyewitness memory, so it is of particular interest that this is coming from a law enforcement publication. Defense lawyers are repeatedly confronted with the critique that these effects have never been corroborated by real field studies, and are thus irrelevant to real-world scenarios -- as if the stressfulness of having a gun in one's face in real life would somehow invert the well-known detrimental effect of a weapon and stress on eyewitness memory in a lab setting. This publication serves as a definitive rebuttal of that critique, where both the FBI and DOJ are on record acknowledging the negative effects of the same factors on the memory of their own officers.

The chapter covers a range of topics, including (1) the reconstructive nature of memory; (2) the mutability of memory -- in particular as a result of improper questioning; (3) the effect of stress on perception and recall; (4) weapon-focus; (5) the tendency to overestimate the duration of a criminal incident; and (6) other perceptual distortions.

This publication is a substantial concession from the law enforcement community that the psychological phenomena that prosecutors routinely dismiss as academic curiosities have real world application, as defense attorneys have known and argued for years.

(All credit to Kate for this great catch.)

No comments: