PSYC39H3 Study Guide - Eyewitness Memory, Recognition Memory, Dependent And Independent Variables
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Chapter 5 – Eyewitness Deception
•Both the police and the courts rely on eyewitness evidence. Eyewitness testimony is one
of the most compelling types of evidence presented in criminal trials.
•A large part of eyewitness testimony rests on memory. There are many stages to
1.Perception/attention stage – when you perceive
2.Encoding stage - when you perceive and pay attention to details in your
3.Short-term memory – has limited capacity and can take in what’s been encoded
4.Long-term memory – information in this memory can be accessed and retrieved
5.Retrieval stage – remembering the information in the memory
•Memory is not like a video recording in which an identical representation of the event is
stored and then can be played on request. Our 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.
•Eyewitness memory can be broadly divided into either recall or recognition memory.
a.Recall memory – refers to reporting details of a previously witnessed even or
b.Recognition memory – refers to determining whether a previously seen item or
person is the same as what is currently being viewed
•Studying eyewitness is usually done through laboratory simulation. To study memory
using laboratory simulation, unknowing participant views a critical event, such as crime,
either through a slide sequence, video recording, or live. Then the participant is asked to
describe target/culprit involved and etc.
•Independent variables: can be either Estimator or system variables. Estimator variables
are variables present at the time of the crime and that cannot be changed (presence of
weapon, lighting, etc) System variables are variables or factors that can be manipulated
to increase (or decrease) eyewitness accuracy, such as the type or procedure used, etc.
This system variable is under the control of justice system.
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•There are 3 general dependent variable in eyewitness studies:
1.Recall of event/crime
2.Recall of culprit
3.Recognition of culprit
•Recall of event and culprit can take two different formats. One being with open-ended
recall also known as free narrative which is when witnesses are asked to either write or
orally state all they remember about the event without the officer asking questions.
•Direct question recall, witnesses are asked a series of specific questions about the crime
•Witness recall can be examined for the amount of information reported, type of
information reported, and accuracy of information reported
•For the recognition of the culprit usually a lineup is used. A lineip is a set of people
presented to the witness, who in turn must state whether the culprit is present and, if so,
which one. There are voice lineups and even clothing lineups presented.
•Primary goal for an officer interviewing an eyewitness is to extract from the witness a
complete and accurate report of what happened. Insufficient information may provide the
officer with few leads to pursue, resulting in a case that will not be solved. If inaccurate
information is supplied, an officer may pursue innocent suspect, thus reducing the
likelihood that the guilty person will be caught.
•In general researchers found that the officer would introduce themselves, ask the
eyewitness to report what they remembered using and open-ended format or free
narrative and then asked the witness a series of direct questions to determine specific
information such as age, height of culprit.
•Fisher et al. found that police officer’s approach limited their ability to collect complete
and accurate information in a number of ways. Police often interrupted in between free
narrative sessions, police may limit amount of information eyewitness have in their
conscious memory when doing so. Second, police questioned eyewitnesses with short
specific questions, this type of questioning results in very short answers. Third police
offers tended to question in random order, which blogs the memory.
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