Chapter 5 – Eyewitness Testimony

Eyewitness testimony: the role of memory:

A large part of eyewitness testimony rests on memory. For example if you are perceiving and paying attention when you look at a strangers face and notice big, busy eyebrows then to some extent the strangers face and eyebrows have been encoded. The encoded information then passes into your short-term holding facility, known as short-term memory (this has a limited capacity).
It is important to remember that not every piece of information will go through all memory stages and factors can affect each stage.
Memory can change each time we retrieve the event; some parts of the event may be embellished or guessed at because we cannot remember all the details.
Two types of memory retrieval:
Eye witness memory retrieval can be broadly partitioned into either recall or recognition memory.
Recall memory – refers to reporting details of a previously witnessed event or person. Reporting details of previously witnessed event/person. Such as what the culprit looked like and what he/she did.
In contrast, recognition memory –refers to determining whether a previously seen item or person is the same as what is currently being viewed. Reporting whether current information is the same as previous information (e.g., lineups). For example, hearing a set of noises and identifying the culprits voice or identifying clothing worn by the culprit during the crime are both recognition tasks.
The Stages of Memory
Perception -> encoding -> short-term -> long-term -> retrieval

How do we study eyewitness issues?
Researchers interested in studying eyewitness issues can examine data from actual crimes. The laboratory simulation study is the most common paradigm used to study eyewitness issues. It’s a variety of research methods: naturalistic environments, archival data, laboratory simulations.

The laboratory simulation:
To study eyewitness memory by using a laboratory simulation, an unknowingly participant views a critical event such as a crime, through a slide sequence, a video recording, or live. The participant is unaware that he or she will be questioned about the event until after the event is witnessed. Now a witness, the participant is asked to describe what happened and the target/culprit involved. Following the descriptions, of what was witnessed, they may be asked to examine a lineup. Many independent variables can be manipulated or examined; however there are only three general dependent variables in the eyewitness studies.

Independent variable. Numerous independent variables can be manipulated or examined within the laboratory simulation. There are two types of independent variables.
Estimator variables: those variables of factors that are present at the time of the crime and that cannot be changed (age, lighting, presence of a weapon, witness was intoxicated). The criminal justice system cannot exert control on these variables and so their effect on eyewitness can be estimated only after the crime.
System variables: those variables or factors that can be manipulated to increase (or decrease) eyewitness accuracy, such as the type of procedure used by police to interview the witness or the type of lineup procedure used to present the suspect to the witness. Both estimator and system variables can be manipulated in eyewitness laboratory studies.

Dependent variable: three general dependent variables in eyewitness studies
1) recall of the event/crime 2) recall of the culprit 3) recognition of the culprit
Recall of culprit has two formats: 1) open ended recall: known as free narrative, witness are asked to either write or orally state all they remember about the event without the officer or experimenter asking Qs.
2) Direct Q recall: witness are asked a series of specific questions about the crime or the culprit.
A witness’s recall of the crime or the culprit can be examined for the following:
Can be asked the amount of