WARM UP #5 1/31
1. What is entomology?2. What is odontology?
THINKING:3. Think of reasons why witnesses are not always
reliable for helping with a case.4. What percent of the time do you think witnesses
get things wrong?5. Why do you think that forensics is needed?
Ch 1 NOTES #3 1/31
Why Forensics?
Two types of evidence:
1. Eyewitness
2. Physical evidence
Witnesses
Until the 1900’s – testimony was most relied on
Many people wrongfully accused Studies show witnesses not very reliable
(25-45% time wrong)
EYEWITNESS ACCURACY
Wells (1998) Studied 40 people convicted, but later
cleared by DNA 36 (90%) of the cases, there were false
eyewitness ID
Buckhout Simulated a crime on a TV newscast Asked for callers 2,145 callers - 85% of the callers had the
suspect description wrong!
Buckhout Staged assault on professor in front of 141
students Week later, students showed a line up:
- 36% IDed a person next to the attacker
- 23 % IDed a person not there
- 40% got it right
Wells and Bradford (1998) 352 people shown a grainy video of a murder
of a security guard Then gave them each a line up of suspects
that were not on the tape 58% picked out a suspect
WHY DO PEOPLE GET IT WRONG?
1. Emotional stress of the event
2. Pressure to choose or help
3. Not actually notice or see things
(eyes can trick you too)
4. Hard to id different race / gender details
When using eyewitness testimony,Separate FACT from OPINION
What did the witness actually see ? Did they see it correctly?
What we think we see and what we really see might not be the same
Test your observation skills
OPTICAL ILLUSIONS
Which side is darker gray?
The gray is the same!
Can you stack the dice like this??
Stare at this and you will soon see a giraffe
Good or evil?
Optical Illusion
Face or a liar?
This is not animated
Not animated
Your eyes are making them move. To test this, stare at one spot in each picture for a few seconds and everything will stop moving
Count the people, then after the shift, count them again
One man? Or 2 people and a pet?
Why need forensics?
to find and interpret REAL evidence; to give SOLID PROOF
You saw a crime scene earlier
1. Describe all you can about the suspect
Most people only see about 3-5 seconds of a crime scene!
THE INNOCENCE PROJECT
Started in 1992
Reopen cases where people claimed they were innocent and the main evidence was eyewitness testimony
Use DNA evidence to give conclusive proof
* 174 out of 200 cases where eyewitness testimony was the main reason for conviction were exonerated (cleared)!!!
Several were in jail over 15 years!
1 How many green?
2 How many blue?
3 How many red?
4 How many in squares?
Answer each question below.
1. What color coffee mug was in the picture? Blue Red Yellow 2. When was the deadline? Yesterday Today Tomorrow 3. What time was on the clock on the wall? 10:40 11:05 1:55 4. How many sticky notes were on the whiteboard? Four Six Eight 5. Which of the following was NOT in the picture? Stapler Trash Can Printer 6. What was the name on the plaque on the desk? Bill Brian Carl 7. What color was the victim's shirt? Black Blue Red 8. How many plants were in the picture? None One Two
9. What was the color of the marker in the desk drawer? Red Blue Green
10. Where was the book in the picture? On a box In the trash can Under the body
Source: http://forensics.rice.edu/html/picture_begin.html
TEST 2
WITNESS RELIABILITYPerson
Q1 Q2 Q3 Q4 Q5 Q6 Q7
1
2
3
4
5
6
7
8
Let’s test your witness ability!
Get out a scrap sheet of paper and put your pencil/ pen down
You will get 10 seconds to look at the items
You will write as many as you remember when done.
Witnesses can help by:
1. A place to start investigations
2. Useful information about crime
3. Making themselves a suspect (lying)
