Transcript File

Pros & Cons of
Testimonial Evidence
Presentation developed by T. Trimpe 2006 http://sciencespot.net/
What is testimonial evidence?
Testimonial evidence includes oral or written statements given to
police as well as testimony in court by people who witnessed an
event.
Eyewitness accounts can be a useful tool in helping investigators
with analyzing a crime scene, but are not viewed to be highly
reliable. In addition, eyewitness identifications (right or wrong) can
have a big influence on the outcome of an investigation or trial.
People are likely to view the same scene in different ways
depending on their positions, line of sight, familiarity with the area,
and other factors that can interfere with a person’s ability to
remember details.
https://www.youtube.com/watch?v=_RLvSGYxDIs
The Bunny Effect
CBS News Video
Memory Challenge
Directions:
You will have 30 seconds to view the next screen.
Try to memorize all 20 items you see!
You are NOT allowed to write anything down
You CANNOT talk to anyone else.
Items to remember ...
Neuroscience for Kids - http://faculty.washington.edu/chudler/puzmatch1.html
What do you remember?
You have 2 minutes to list as many of the items as you can!
How did you do?
All 20 – Awesome
15-19 – Great
10-14 – Pretty swell
5-9 – Could be better
4 or Less – Wake up
Did you know?
According to The Innocence Project (2008)
"Eyewitness misidentification is the single greatest
cause of wrongful convictions nationwide, playing a
role in more than 75% of convictions overturned
through DNA testing." Still, the criminal justice
system profoundly relies on eyewitness identification
and testimony for investigating and prosecuting crimes
(Wells & Olson, 2003).
What factors affect a person’s memory
and their ability to identify a suspect?
Source: http://www.helium.com/items/1276135-accurate-eyewitness-accounts
The Case of Jennifer Thompson
and Ronald Cotton
• http://www.youtube.com/watch?v=u-SBTRLoPuo
• http://www.youtube.com/watch?v=GtelV9lmzQc
* As you watch answer the questions
Forensic Science: Fundamentals
& Investigations, Chapter 1
7
Witness Factors
• Age may play a role in the accuracy of an eyewitness’ statement or
identification of a suspect. Studies have shown that when a lineup
contains the actual culprit, both young children and elderly perform well,
but when the lineup does not contain the culprit there is a higher rate of
mistaken identifications.
• The race of the witness may also play a role. The Cross Race Effect
(CRE) is a phenomenon in which people are better at recognizing faces
of their own race rather than those of other races.
• The use of drugs can alter a person’s ability to recall the events of a
crime even after they are no longer under the influence.
• A person’s memory of an event can be influenced by other witnesses,
investigators, and/or the media. Investigators use open-ended
questioning and follow procedures for conducting line-ups to limit their
influence on a witness’ memory of an event or identification of a suspect.
Source: http://www.helium.com/items/1276135-accurate-eyewitness-accounts
Crime Scene & Suspect Factors
• A crime that is extremely traumatic for an eyewitness may affect his/her
recall of the event. For example, a witness confronted with a weapon tends
to focus on the weapon rather than the perpetrator’s face.
A suspect with a weapon – Stress level
• Someone who is able to focus on a perpetrator's face for a minute or longer
will tend to have a more accurate memory than someone who saw the person
for only a few seconds. Longer time to focus on the perp.
• Studies have shown that faces that are either highly attractive, highly
unattractive, or distinctive are more likely to be accurately recognized.
Simple disguises, such as hats or sunglasses, can interfere with accurate
eyewitness identification. However, body piercings and tattoos increases the
likelihood of an accurate identification. Standout features on the perp.
• The time of day in which the crime occurred as well as a person’s view of
the scene may affect what a he/she is able to see. Day vs. Night
• In addition, a person who is familiar with the area in which the crime took
place, may have a better recall of the positions of the victims or suspects.
• In a well know area
Source: http://www.helium.com/items/1276135-accurate-eyewitness-accounts
Crime Scene Challenge
• Now that your eyes and brain are warmed up, let’s
test your observation skills a bit more.
• You will have 2 minutes to study the photograph of a
crime scene on the next slide.
• Try to pay attention to details as you will be asked 10
questions about the crime scene!
• You are not allowed to write anything down until
after the time is up.
• Ready?
Answer each question below.
1. What color coffee mug was in the picture?
2. When was the deadline?
Yesterday
Blue
Red
Today
3. What time was on the clock on the wall?
Yellow
Tomorrow
10:40
11:05
4. How many sticky notes were on the whiteboard?
Four
Six
5. Which of the following was NOT in the picture? Stapler
6. What was the name on the plaque on the desk?
7. What color was the victim's shirt?
Black
8. How many plants were in the picture?
None
Bill
Blue
10. Where was the book in the picture? On a box
Source: http://forensics.rice.edu/html/picture_begin.html
Eight
Trash Can
Brian
Printer
Carl
Red
One
9. What was the color of the marker in the desk drawer?
1:55
Two
Red
In the trash can
Blue
Green
Under the body
Flashbulb Memories
• Many victims of crimes have something
that is called a flashbulb memory
• This is a vivid recollection of dramatic or
emotionally charged events
• Example: Can anyone tell me what you
were doing when…?
– You first saw or heard about September 11
– Barack Obama became president
– Michael Jackson died
You Be the Eyewitness
• Imagine you are at a gas station buying
milk
• A man walks in, threatens the employee at
the counter, robs the cash register, and
runs out
• The entire ordeal lasts about five seconds
• This is the man you saw…
You Be the Eyewitness
• The police have asked you to help them
identify the perpetrator
• They will show you a set of pictures, and it
is your responsibility to select the picture of
the man you saw rob the gas station…
How Did You Do?
• So, which picture did you choose?
• And the correct answer was... #2
• Were you right?
• What does this tell you about eyewitness
testimony?
According to Research…
• Studies show that the longer it takes an
eyewitness to decide if the perpetrator is in
a lineup, the less confident they actually
are about their decision
• Why?
• Eyewitnesses typically take several
minutes to point out the perpetrator
because they often feel pressured to
choose the correct one
• However, if they are truly confident, they
should be able to decide in under 10
Facial Composites
Investigators work with sketch artists and eyewitnesses to create
facial composites, or sketches of a person’s face. Today many
police departments are using facial reconstruction software to
help them with this task.
The composite may be used internally to assist officers in
identifying the suspect or used externally through local media
(radio, TV, and newspaper) to solicit leads from citizens.
FACES – A software program that
offers many options to help you
recreate a person’s facial features.
You will have a chance to try to create a facial composite. You
will need to pay close attention to the following features:
The shape of the face
The shape of the jaw
The shape of the eyes
The shape of the nose
The width of the neck
The shape & protrusion of the ears
The presence of facial piercing
The presence of facial hair, its color, & location
The presence of facial markings, such as scars or tattoos
Forehead or other facial lines
The presence of eyeglasses or sunglasses
The length, color, & texture of the person’s hair
Choosing From a Lineup
• Research from Buckhout (1974) and Wells
(1993) indicate that an eyewitness is more
likely to falsely identify a person in a set of
lineup photographs is there is anything that
separates one picture from another
• For example:
– If one picture is larger than the others
– If facial features in all the photographs are not
identical
More Research…
• Malpass and Devine (1981)
– Half of their participants in the staged act of
vandalism were told that the perpetrator was in
the lineup while the other half were told that
the perpetrator may or may not be present
– Results: the participants who were led to
believe that the perpetrator was present felt
compelled to pick someone, and more often
than not, they chose an innocent person
What Makes Memories
Inaccurate?
• With someone sitting next to you, I’d like
you to do some brainstorming…
• Think about a situation in which you
observe a crime (let’s say, in this case, a
robbery)
• If you were asked a few days later to recall
everything that you saw, including what the
perpetrator looked like, what he/she was
wearing, etc., what sorts of factors would
affect your memory?
Some Possible Explanations
•
•
•
•
Poor lighting
Distance in viewing
Short exposure
Something covering the perpetrator’s face
(i.e., a mask)
• Heightened stress and anxiety levels
• Presence of a weapon
• The own-race bias (the tendency for people
to recognize faces of their own race more
accurately than faces of other races)