Forensic psychology
University of Groningen, PSB3N-MO4
Chapter 6 - Eyewitness Evidence 1
The Return of the Repressed: The Persistent and Problematic Claims of Long-Forgotten
Trauma 8
What Science Tells us About False and Repressed Memories 15
Chapter 7 - Interviewing Witnesses 18
Chapter 8 - Interviewing Suspects 26
Chapter 9 - Detecting Deception 31
Chapter 5 - Effects of Interpersonal Crime on Victims 38
We’re all victims here: toward a psychology of revenge 45
The impact of criminal justice involvement on victim’s mental health 48
Accommodating the expressive function of victim impact statements: the scope for victims’
voices in dutch courtrooms 51
Contact between victims and offenders in forensic mental health settings: an exploratory
study 56
Chapter 1 - Psychological approaches to understanding crime 59
Chapter 11 - Interpersonal Violence and Stalking 69
Chapter 2 - Developmental and Psychological Theories of Offending 74
Chapter 12 - Terrorism 81
Chapter 15 - Identifying perpetrators 87
Chapter 17 - Crime and Punishment: What works? 93
Chapter 19 - Treating Dangerous Offenders 99
Chapter 20 - Interventions with female offenders 106
Chapter 22 - Interventions with Mentally Disordered Offenders 112
Chapter 23 - The rehabilitation of offenders: good lives and risk reduction 119
Human Aggression 126
From Predicting Dangerousness to Assessing and Managing Risk for Violence - A Journey
Across 4 generations 136
I3 Theory: Instigating, Impelling, and Inhibiting Factors in Aggression 142
Rehabilitating Criminal Justice Policy and Practice 147
Treating Offenders With Mental Illness: A Research Synthesis 152
,Chapter 6 - Eyewitness Evidence
Chapter provides an overview of major current research topics concerning witness
memory. Consider how attention and different stages of memory relate to what witnesses
remember about events.
Witness testimony plays a vital role in criminal investigation and in the courtroom, providing
a first-hand account of a criminal even to allow a judge and jury to decide the guilt of a
defendant.
3 stages of memory:
1. encoding
2. storage
3. retrieval
→ at each stage factors can operate to undermine the quality and accuracy of memory;
which has important implications for the criminal justice system when trying to secure
convictions
(1) Encoding → involves the creation of a memory by an observer.
What can go wrong: the quality can be compromised by the extent to which the observer is
paying attention.
(2) Storage (or retention) → after the memory has been encoded the observer will store the
memory for later retrieval.
What can go wrong: the accuracy of one witness’ stored memory might be influenced by
hearing other people describe the attack incorrectly.
→ research shows just how vulnerable stored memories are to external influences, and how
resulting representations often include a complete mixture of correct and incorrect
information
(3) Retrieval → the process by which memory is accessed, and in the legal contexts,
involves the witness explaining what happened during the event of the police.
What can go wrong: witnesses may encounter difficulty accessing their memories (e.g.
unfamiliar environment, pressure, detailed questions)
→ research shows that something as simple as closing your eyes during an interview might
significantly improve the quality and accuracy of the recall, making it easier for witnesses to
visualize a past event
To make inferences about real eyewitnesses, owing to ethical and practical
considerations, participants often view videos of crimes as part of eyewitness experiments.
Later, their memory is tested for the event in the video. However, the unique nature of
witnessing a real crime might influence how well events are remembered.
2 types of factors affecting eyewitness accuracy:
1. estimator variables; cannot be controlled by the legal justice system, so their impact
has to be estimated by legal professionals
1
, → primarily related to the encoding and storage stages of memory, particularly the
characteristics of the crime event
→ some examples:
a. how stressed witness was
b. how far away the witness was at the time of the event
c. what the lighting was like
d. whether the witness’ memory was later contaminated by conflicting accounts
2. system variables; are most closely related to the retrieval stage of memory, and can
be controlled by the criminal justice system
→ e.g. the kind of questions asked (open vs close)
Factors affecting the quality and accuracy of memory encoding
● Stress
● Weapon focus
● Change blindness
● Stereotyping
● Intoxication
● Age
Stress
During a crime it is likely that witnesses will experience relatively high levels of stress, which
can negatively affect the clarity and accuracy of the memory they encode.
Research on stress and memory often refers to the Yerkes-Dodson Law which plots the
relationship as an inverted U-shaped curve; this law may help to explain some of the
contradictory results in the literature.
= according to this law, memory performance is optimal under moderate stress levels, but
declines at the two extremes of physiological arousal
However, stress does not always affect recall accuracy. In fact, the most stressed
witnesses recalled the event more accurately than those who reported being less stressed;
however, outside the lab it is difficult to control for other variables. People who were more
stressed were also closer to the shooting.
It is also important to consider the relationship between memory accuracy and the type of
information recalled in stressful conditions.
→ traumatic memories (by definition are extremely stressful) are often very accurate
→ some psychologists have presented evidence that in times of high stress and
physiological arousal, attention narrows to central aspects of an event; means that more
peripheral aspects are neglected, and encoded less well, whilst central information may be
remembered very accurately
→ but there is also contradicting evidence
Weapon focus = the phenomenon in which, when confronted with a gun or knife, one might
focus a lot of attention on the weapon due to fear or surprise, but fail to notice other details
that could be relevant to the police.
→ weapon effect may not be as large as psychology studies suggest
2
, → unless the crime was recorded on CCTV, there are problems with using real crimes to
make judgements about how memory operates, as it is impossible to compare the
witnesses’ memory to what actually happened (the ground truth)
→ weapon focus diminishes the longer the witness is exposed to the perpetrator, as
exposure length increases, witnesses shift their attention away from the weapon and
towards the perpetrator
2 possible explanations for the weapon-focus phenomenon:
1. Cue utilization hypothesis; argues that people narrow their attention to the weapon
because of the threat associated with it
→ associated with the threat hypothesis, research showed that the presence of a
‘frightening’ object resulted in children remembering less about the researcher’s
appearance than those who encountered neutral objects
2. The weapons capture attention because it is so unusual to encounter one in
everyday life
→ studies have shown that unusual items specific to a certain context have similarly
detrimental effect on memory
Change blindness = whilst observing a crime, you might shift your attention around, looking
in one direction then another, to try and make sense of what is happening, if a change
occurs in the brief time you’re not looking, you might not notice it when you revert your
attention.
→ skilled observers of crime, are just as susceptible to change blindness as laypeople
→ phenomenon is caused by lapses in perception
→ Levin, Simons, Angelone and Chabris explained this phenomenon as being due to the
lack of well-established object/person representation, which might allow the new
representation of the object/person to overwrite the first
→ participants were less likely to notice changes in identity when a crime event featured a
continuity illusion: an “innocent” person walked behind a stack of boxes and the
perpetrator emerged from the other side
Crime events can be highly complex and difficult to make sense of, resulting in a high
cognitive load at encoding. Available information from the crime alone can be confusing, so
as a way of creating a more coherent memory, people might unknowingly make use of
schemas and scripts.
→ e.g. thanks to books, films and TV, we probably all have a representation of what might
happen during a shoplifting incident, what the offender would do, and how he/she would act;
this representation might be used to try and fill memory gaps
→ the higher the cognitive load, the more likely people are to employ stereotypes to increase
coherence
Whether or not information is consistent or inconsistent with stereotypes and schemas
influences how well it is remembered.
→ encoded information that is consistent with a stereotype or schema might actually be
preserved very well
When a crime occurs, it is relatively common for the witness or victim to be intoxicated.
3
University of Groningen, PSB3N-MO4
Chapter 6 - Eyewitness Evidence 1
The Return of the Repressed: The Persistent and Problematic Claims of Long-Forgotten
Trauma 8
What Science Tells us About False and Repressed Memories 15
Chapter 7 - Interviewing Witnesses 18
Chapter 8 - Interviewing Suspects 26
Chapter 9 - Detecting Deception 31
Chapter 5 - Effects of Interpersonal Crime on Victims 38
We’re all victims here: toward a psychology of revenge 45
The impact of criminal justice involvement on victim’s mental health 48
Accommodating the expressive function of victim impact statements: the scope for victims’
voices in dutch courtrooms 51
Contact between victims and offenders in forensic mental health settings: an exploratory
study 56
Chapter 1 - Psychological approaches to understanding crime 59
Chapter 11 - Interpersonal Violence and Stalking 69
Chapter 2 - Developmental and Psychological Theories of Offending 74
Chapter 12 - Terrorism 81
Chapter 15 - Identifying perpetrators 87
Chapter 17 - Crime and Punishment: What works? 93
Chapter 19 - Treating Dangerous Offenders 99
Chapter 20 - Interventions with female offenders 106
Chapter 22 - Interventions with Mentally Disordered Offenders 112
Chapter 23 - The rehabilitation of offenders: good lives and risk reduction 119
Human Aggression 126
From Predicting Dangerousness to Assessing and Managing Risk for Violence - A Journey
Across 4 generations 136
I3 Theory: Instigating, Impelling, and Inhibiting Factors in Aggression 142
Rehabilitating Criminal Justice Policy and Practice 147
Treating Offenders With Mental Illness: A Research Synthesis 152
,Chapter 6 - Eyewitness Evidence
Chapter provides an overview of major current research topics concerning witness
memory. Consider how attention and different stages of memory relate to what witnesses
remember about events.
Witness testimony plays a vital role in criminal investigation and in the courtroom, providing
a first-hand account of a criminal even to allow a judge and jury to decide the guilt of a
defendant.
3 stages of memory:
1. encoding
2. storage
3. retrieval
→ at each stage factors can operate to undermine the quality and accuracy of memory;
which has important implications for the criminal justice system when trying to secure
convictions
(1) Encoding → involves the creation of a memory by an observer.
What can go wrong: the quality can be compromised by the extent to which the observer is
paying attention.
(2) Storage (or retention) → after the memory has been encoded the observer will store the
memory for later retrieval.
What can go wrong: the accuracy of one witness’ stored memory might be influenced by
hearing other people describe the attack incorrectly.
→ research shows just how vulnerable stored memories are to external influences, and how
resulting representations often include a complete mixture of correct and incorrect
information
(3) Retrieval → the process by which memory is accessed, and in the legal contexts,
involves the witness explaining what happened during the event of the police.
What can go wrong: witnesses may encounter difficulty accessing their memories (e.g.
unfamiliar environment, pressure, detailed questions)
→ research shows that something as simple as closing your eyes during an interview might
significantly improve the quality and accuracy of the recall, making it easier for witnesses to
visualize a past event
To make inferences about real eyewitnesses, owing to ethical and practical
considerations, participants often view videos of crimes as part of eyewitness experiments.
Later, their memory is tested for the event in the video. However, the unique nature of
witnessing a real crime might influence how well events are remembered.
2 types of factors affecting eyewitness accuracy:
1. estimator variables; cannot be controlled by the legal justice system, so their impact
has to be estimated by legal professionals
1
, → primarily related to the encoding and storage stages of memory, particularly the
characteristics of the crime event
→ some examples:
a. how stressed witness was
b. how far away the witness was at the time of the event
c. what the lighting was like
d. whether the witness’ memory was later contaminated by conflicting accounts
2. system variables; are most closely related to the retrieval stage of memory, and can
be controlled by the criminal justice system
→ e.g. the kind of questions asked (open vs close)
Factors affecting the quality and accuracy of memory encoding
● Stress
● Weapon focus
● Change blindness
● Stereotyping
● Intoxication
● Age
Stress
During a crime it is likely that witnesses will experience relatively high levels of stress, which
can negatively affect the clarity and accuracy of the memory they encode.
Research on stress and memory often refers to the Yerkes-Dodson Law which plots the
relationship as an inverted U-shaped curve; this law may help to explain some of the
contradictory results in the literature.
= according to this law, memory performance is optimal under moderate stress levels, but
declines at the two extremes of physiological arousal
However, stress does not always affect recall accuracy. In fact, the most stressed
witnesses recalled the event more accurately than those who reported being less stressed;
however, outside the lab it is difficult to control for other variables. People who were more
stressed were also closer to the shooting.
It is also important to consider the relationship between memory accuracy and the type of
information recalled in stressful conditions.
→ traumatic memories (by definition are extremely stressful) are often very accurate
→ some psychologists have presented evidence that in times of high stress and
physiological arousal, attention narrows to central aspects of an event; means that more
peripheral aspects are neglected, and encoded less well, whilst central information may be
remembered very accurately
→ but there is also contradicting evidence
Weapon focus = the phenomenon in which, when confronted with a gun or knife, one might
focus a lot of attention on the weapon due to fear or surprise, but fail to notice other details
that could be relevant to the police.
→ weapon effect may not be as large as psychology studies suggest
2
, → unless the crime was recorded on CCTV, there are problems with using real crimes to
make judgements about how memory operates, as it is impossible to compare the
witnesses’ memory to what actually happened (the ground truth)
→ weapon focus diminishes the longer the witness is exposed to the perpetrator, as
exposure length increases, witnesses shift their attention away from the weapon and
towards the perpetrator
2 possible explanations for the weapon-focus phenomenon:
1. Cue utilization hypothesis; argues that people narrow their attention to the weapon
because of the threat associated with it
→ associated with the threat hypothesis, research showed that the presence of a
‘frightening’ object resulted in children remembering less about the researcher’s
appearance than those who encountered neutral objects
2. The weapons capture attention because it is so unusual to encounter one in
everyday life
→ studies have shown that unusual items specific to a certain context have similarly
detrimental effect on memory
Change blindness = whilst observing a crime, you might shift your attention around, looking
in one direction then another, to try and make sense of what is happening, if a change
occurs in the brief time you’re not looking, you might not notice it when you revert your
attention.
→ skilled observers of crime, are just as susceptible to change blindness as laypeople
→ phenomenon is caused by lapses in perception
→ Levin, Simons, Angelone and Chabris explained this phenomenon as being due to the
lack of well-established object/person representation, which might allow the new
representation of the object/person to overwrite the first
→ participants were less likely to notice changes in identity when a crime event featured a
continuity illusion: an “innocent” person walked behind a stack of boxes and the
perpetrator emerged from the other side
Crime events can be highly complex and difficult to make sense of, resulting in a high
cognitive load at encoding. Available information from the crime alone can be confusing, so
as a way of creating a more coherent memory, people might unknowingly make use of
schemas and scripts.
→ e.g. thanks to books, films and TV, we probably all have a representation of what might
happen during a shoplifting incident, what the offender would do, and how he/she would act;
this representation might be used to try and fill memory gaps
→ the higher the cognitive load, the more likely people are to employ stereotypes to increase
coherence
Whether or not information is consistent or inconsistent with stereotypes and schemas
influences how well it is remembered.
→ encoded information that is consistent with a stereotype or schema might actually be
preserved very well
When a crime occurs, it is relatively common for the witness or victim to be intoxicated.
3
