2. 1. Personal
Observation
– We value eyewitness testimony as evidence.
This Photo by Unknown Author is licensed under CC BY-ND
3. Eyewitnesses
to the Sniper?
As The Washington Post and other sources noted, the witnesses gave
"vague and inconsistent accounts," disagreeing on virtually all details
other than the sex of the apparent shooter. All the witnesses agreed
they'd seen a man, but some reportedly described a man "with dark
skin, others with olive complexion, of Middle Eastern appearance or
Hispanic"; one apparently said he was "not white, not black." Such
imprecision is mirrored in the descriptions of the killer's (or killers')
vehicle, which has been variously described a white Chevy Astrovan,
a Ford Econoliner, and a white panel truck.
Gillespie, Nick. “Shooting Blind.” Reason Online.” 17 Oct 2002. (6 Nov.
2002)
4. – Even the expectation of a
composite sketch—based on
accounts from eyewitnesses to
Monday's shooting outside a
Fairfax County, Virginia, Home
Depot—came to nothing.
"Because of darkness and
distance and perhaps
excitement and adrenaline at
the time, we are unable to
come up with a composite,"
said Montgomery County police
Capt. Nancy Demme.
5. Issues?
– Problems:
– See or hear what we wish to
– Remember aspects of an
experience that are most
consistent with our background
– What we see or hear is filtered
through our values, attitudes
and expectations.
6. Eyewitness Testimony
Wrongfully Imprisoned
At the age of 39, James Newsome walked out of a maximum-
security prison in Illinois after 15 years of wrongful incarceration.
Newsome was convicted and sentenced to life in prison after three
witnesses identified him as the man who shot and killed a 72-year-
old grocery store owner on the South Side of Chicago even though
his fingerprints didn’t match those at the scene. But in 1994,
fingerprint technology proved the real perpetrator was a man on
death row. Newsome was given a settlement of $140,000 by the
state, but he didn’t think that was enough of an apology. Now he’s
suing the police officers and the Chicago Police Department for
millions for gross misconduct.
Sinatra, Amy. “It’s Him – Or Is It?” ABCnews.com.”
http://abcnews.go.com/sections/us/DailyNews/eyewitness_testimony.html (6 Nov. 2002)
7. 2. Research Studies
– A systematic collection of data by people
trained to do scientific research.
– This kind of evidence CAN BE very
dependable, but the research must use the
scientific method.
8. Examples
Studies show that violent computer
games cause aggressive behavior
in children.
A recent report indicates that female
college students are intimidated by
computer classes.
9. A few clues
– Studies have shown. . .
– Research investigators found. . .
– A report in the New England
Journal of Medicine indicated. .
.
10. Research Findings
as Evidence is
Good When. . .
– Minimizing extraneous (unnecessary)
factors that might affect the accuracy and
interpretation
– Use multiple observers
– Do in a controlled environment like a lab
This Photo by Unknown Author is licensed under CC BY-SA
11. Heads up with
social sciences
– Hard to apply in studies of the social world
and human behavior. People may behave
differently when they know they’re being
watched or respond differently in interviews
or on surveys.
12. – Publicly verifiable data
The data must be obtained under conditions
such that other qualified people can make
similar observations and obtain the same
results (replication)
– Precision in Language.
The language must be precise and consistent.
– IRB Certified (Institutional Review Board)
Scientific Method: Control
13. Problems in
Research Findings
• Research varies in quality
• Research findings often contradict one
another.
• Researchers have expectations, attitudes,
values, and needs that bias the question they
ask and the way they conduct research.
14. Problems in
Research Findings
– Speakers and writers often distort or simplify
research conclusions
– Research facts change over time
– The need for financial gain, status, security,
and other factors can affect research
outcomes.
15. Evaluating
Research #1
– What is the quality of the
source?
– Most dependable are
journals where the study is
reviewed by a panel of
experts, like the Journal of
the American Medical
Association.
16. Evaluating
Research
– Has the study been replicated?
– Have other studies shown
consistent results?
– Are conditions in the research
artificial?
– How similar are the conditions
under which the research
study was conducted to the
situation the researcher is
generalizing about?
This Photo by Unknown Author is licensed under CC BY
17. Evaluating
Research
– Is there a reason for someone to have
distorted the research?
Money, position, prestige..
– Has the study been selectively chosen?
– Are there studies with contradictory
results that were not mentioned?
– How far can we generalize, given the
research sample?
This Photo by Unknown Author is licensed under CC BY
18. Generalizing
Based on a
Sample
The sample must
be:
Large enough to
justify the
conclusion. Usually
the more events or
people observed,
or surveyed, the
better.
Possess as much
diversity (breadth)
as the types of
events about which
conclusions are
drawn.
As random as
possible to prevent
getting groups of
people that have
biased
characteristics.
19. Surveys &
Questionnaires
-possible
issues
• The survey has to be answered truthfully. People
often give answers they think they’re supposed to
give.
• Questions may be ambiguously worded.
• The wording of the question may be biased.
• Answers can vary based on the position of the
question in the survey and how the survey is
presented.
20. Analogies as
Evidence
– Proving a conclusion about
something by relying on
similarity (comparing) to
something more familiar or that
is easier to study.
21. Examples
– A researcher may report that when rats
are confined to an overcrowded cage,
they exhibit antisocial behavior; a
conclusion is then drawn about
humans, comparing crowded rats to
city dwellers. The researcher may imply
that crime is a result of overcrowded
conditions.
This Photo by Unknown Author is licensed under CC BY-SA-NC
22. Double Check
– The number of ways the two
things being compared are
similar.
– The relevance of the
similarities and the
differences.
– Try to generate your own
alternative analogies to better
understand.
