Evidence and eyewitness

Eyewitness Testimony

Can We Trust Human Memory?

There are TWO types of evidence

Direct Evidence: Directly proves a fact without any
assumption necessary. Examples: eyewitness testimony,
audio recording, video recordings, and confessions.

Circumstantial Evidence: Evidence that implies that
something occurs, but does not prove it. Examples include:
physical evidence, behavior, and scientific evidence.

An example:

What do you think?

You are on the jury of a theft case. The defense

attorney provides three pieces of circumstantial

evidence that the Suspect is innocent. The

prosecuting attorney then brings up two

eyewitnesses (direct evidence) who point to the

Suspect and say that they saw him commit the

robbery.

Open Ended

Which evidence is more reliable? Would you convict the
Suspect based on the eye witness direct evidence, or release him based on the circumstantial evidence?

Forensic Science = Circumstantial Evidence

Forensic Scientists and Crime Scene

Investigators deal only with

circumstantial evidence.

It is the job of CSI and Forensic technicians

to analyze evidence found at a crime scene

so that it is available for police, detectives,

and ultimately, the judge and jury of a court

case.

Eye Witness Testimony: Is It Reliable?

But is circumstantial evidence as

important as direct eye witness evidence?

In the next few slides, you will explore the

reliability of eyewitness (direct) evidence

and come to understand the importance

of forensic circumstantial evidence.

First, we will test your own skills of

observation!

Test your skills of observation

How observant are you?

Before you watch this video, I

will let you in on its secret.

There are twenty one changes of

props and items in the room

during the course of the scene!

See if you can spot any of

them…

Call them out when

you see them!

How Observant Are You?

This challenge is

a bit more simple:

just one thing to

focus on.

How many

passes did you

count? I'll be

asking you after!

Watch until 0:39 seconds then

PAUSE

Open Ended

How many passes did you count?

How Observant Are You?

Has anyone seen

this video before?

How Observant Are You?

Did you spot the

gorilla?

Studies show that nearly
50% of people who see
this video for the first time
do not notice the gorilla!

Now try another!

Follow the cup with the

chocolate under it.

Watch until 2.05 then stop.

Poll

Were you successful?

• I got it the first itme!

• I got it the second time!

• Neither time.

Poll

Did you notice the duck?

• Yes

• No

Poll

Did you notice the extra hand?

• Yes

• No

Poll

Did you notice the color change?

• Yes

• No

Open Ended

Now think about eyewitness testimony. When
a detective asks a witness if he or she ‘noticed
anything on the night of the murder’ - how
reliable is the witness’s answer? Explain your
thoughts.

CNN: Do You Know What You Saw?

Open Ended

Does the information in
this video clip surprise
you? What are your
thoughts/feelings as you
learn about the reliability
of eyewitness testimony?

Open Ended

Given what you have learned about eye
witness reliability (from the gorilla/cup
observations and news clip) summarize the
importance of circumstantial evidence
(Forensics!) in solving crime.