forensics-eyewitness notes

Do you see what I see? Forensic Science Eyewitness Testimony

Upload: leah-morgan

Post on 01-Jul-2015




0 download


Class notes from the eyewitness lecture


Page 1: Forensics-eyewitness notes

Do you see what I see?

Forensic ScienceEyewitness

Testimony Lecture

Page 2: Forensics-eyewitness notes

Eyewitness Testimony

• Eyewitness testimony has long been considered the best evidence in pursuing justice

• Juries have convicted suspects solely on the basis of eyewitness testimony.

• In some cases, more weight has been placed on eyewitness testimony when forensic evidence contradicted it

Page 3: Forensics-eyewitness notes

Fallibility• Eyewitness testimony, especially when

guided by the police, is notoriously unreliable.

• Eyewitness misidentifications contributed to over 75% of the more than 220 wrongful convictions in the United States overturned by post-conviction DNA evidence.

Page 4: Forensics-eyewitness notes

Line-Up Identifications

• Describing what a suspect looks like and then choosing that suspect from a line-up is known to be incorrect some of the time.

• Research has demonstrated that when viewing several subjects at once, witnesses tend to choose the person who looks the most like – but may not actually be – the perpetrator.

Page 5: Forensics-eyewitness notes

How observant are you?

• There are many things we see every day but we don’t really “see” the details.

• On the next slide, choose the picture that correctly depicts the penny.

Page 6: Forensics-eyewitness notes

Which penny?

Page 7: Forensics-eyewitness notes

Which penny?

Page 8: Forensics-eyewitness notes

Recognizing Faces

• We are not much better at recognizing faces, especially those we have not see before.

• Our minds classify facial features into broad groups and then individuate specific details to recognize faces.

• Most people will choose a person who looks “most like” the person they have in mind.

Page 9: Forensics-eyewitness notes

Try this…• The following person was seen by several

witnesses robbing a convenience store.

Page 10: Forensics-eyewitness notes

• Most of the witnesses could agree on the features of the suspect and felt comfortable identifying him from a photo line-up.

Page 11: Forensics-eyewitness notes

Which one is it?

Page 12: Forensics-eyewitness notes

The Wrong Man• Although this man does look

similar to the man in the surveillance video, he was not the perpetrator. In fact, the actual criminal was not even in the line-up.

• The witnesses were “sure” they picked the right man.

• They instead chose the man who looked closest to what they remember.

Page 13: Forensics-eyewitness notes

Watch and Learn

Test your powers of observation with this video

Watch carefully!

• Whodunit?

Page 14: Forensics-eyewitness notes

So how good are you really?

• Put everything away and take out a pen.• Answer the questions on the paper

provided.• No talking about your answers, just write

them down.• Ready?

Page 15: Forensics-eyewitness notes

• During the lecture, someone came into the classroom? Who was it?

• What time did the person come in?• What did the person take from the room?• Describe what the person was wearing.• What height was the person?• Describe the facial features of the person.