Eyewitness Memory

Bob CampbellLourdes University

Eyewitness Testimony Loftus & Palmer (1974) Contact speed was 31.8 mph Smashed speed was 40.8 mph 12% (contact) incorrectly recalled

broken glass 32% (smashed) incorrectly recalled

broken glass

The Problem of Duality of Error in Law

Convicting the innocent Acquitting the guilty Beyond a reasonable doubt protects the

individual at possible cost to society Preponderance of evidence protects the

society at possible cost to the individual Hammond (1996)

Estimator and System Variables

Some factors that influence the accuracy of eyewitness testimony are beyond the control of the justice system

Other factors that influence the accuracy of eyewitness testimony can be controlled by the justice system

Wells (1978)

At the Scene of an Accident or Crime

The behavior of the officer at the scene of an accident or crime is a system variable which may alter the memory of the witness

Expectations Hall et al. (1978) Expectations of the police officer at

the scene may influence the witness The officer at the scene must be

careful not to impart information to the witness either verbally or nonverbally

Type of Question Asked Free Narrative such as “What did you

see?” Controlled Narrative such as “What

was the assailant wearing?” Interrogatory Reports such as

“Where did the incident happen: in a lot, in the street, or on the sidewalk?”

Accuracy versus Completeness

Accuracy: Free, Controlled, Interrogatory

Completeness: Interrogatory, Controlled, Free

Officer on the scene must be aware of the need to balance the quest for accuracy with the need for completeness

The Effects of DNA Evidence

A recent study identified 62 individuals convicted of crimes they did not commit

52 cases involved mistaken identification on the part of 77 highly confident eyewitnesses

Scheck, Neufeld, & Dwyer (2000) As of 2010, 254 individuals exonerated

as a result of “project innocence”

The Guide In 1999 the US Justice Department

created a guide for law enforcement that details the handling of an eyewitness to an accident or crime

Panel consisted of 34 experts from law enforcement, the legal profession, and academia

Recommendations Encourage rapport with the

eyewitness and encourage them to talk freely

Conduct the interview at a slow pace and ask primarily open ended questions

Communicate your investigative needs to the witness

System Variables Avoid surrounding a potentially

innocent suspect with dissimilar fillers The eyewitness should be instructed

prior to viewing the lineups that the suspect may or may not be in the lineup

System Variables Continued Present sequential rather than

simultaneous lineups Avoid giving the eyewitness feedback

about the accuracy of the identification after a selection has been made

This must be done before assessing the confidence of the eyewitness

Eyewitness Research Campbell (2003) Control 45% accuracy 66%

confidence Exp 75% accuracy 74% confidence

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