Chapter 16
Social Psychology and
the Law
Social Psychology and the Law

Studying the legal system helps
psychologists see how behavior
occurs in complex, personally
relevant, and emotion-laden contests.
Eyewitness Testimony

Eyewitness identifications are
frequently inaccurate.
Eyewitness Testimony

The three basic processes of
acquisition, storage, and retrieval
influence eyewitness memory, just as
they influence all memory.
Eyewitness Testimony


Two groups of factors influence
eyewitness identification
Estimator variables


concern the eyewitness and the situation
System variables

are under the direct control of the
criminal justice or legal system.
Eyewitness Testimony

Viewing Opportunity


The longer witnesses look and the more
attention they are able to pay, the more
accurate their identifications
However, witnesses are just as likely to
think they can make an identification if
they have witnessed an event under poor
viewing conditions.
Eyewitness Testimony

Stress and Arousal

Stress increases memory for the event
itself but decreases memory for what
preceded and followed the incident
Eyewitness Testimony

Weapon Focus Effect


People tend to keep their eye on weapons
because of their danger and novelty
This distracts their attention from the
robbers
Eyewitness Testimony

Own-Race Bias


People are more accurate in identifying
members of their own race
Own-race bias decreases with
experience with other groups

Thus blacks are more accurate in identifying
whites than vice versa.
Eyewitness Testimony

Retention Interval

Accuracy drops with time rapidly at
first, then levels off.
Eyewitness Testimony

Suggestive Questioning


The way witnesses are questioned influences
their memories of the event.
Some questions are suggestive but not
deliberately misleading


E.g. Loftus & Palmer found that people said a car had
been going faster in an accident if they asked about
its speed when it “smashed” into the other car as
opposed to “hit” it
Other questions are deliberately misleading,
asking about nonexistent details.
Eyewitness Testimony

Three hypotheses for how post-event
information affects memory



over-writing
forgetting
source monitoring


People retain memories of both the event
and any post-event information but cannot
identify the source of the memories
Evidence supports the latter.
Eyewitness Testimony

Lineup Biases

The way lineups are conducted can have
a tremendous effect on the accuracy of
eyewitness identification.
Eyewitness Testimony

Show-ups


Simultaneous lineups


asks witnesses to indicate whether or
not a single witness is the perpetrator
show the witness several potential
suspects at the same time.
Sequential lineups

show potential suspects one at a time
Eyewitness Testimony

Sequential lineups allow the most
careful attention to each person and
the most careful decision-making and
are most accurate.
Eyewitness Testimony

Another aspect of lineups is choosing
foils (people other than the suspect
in the lineup).

Identifications are most accurate when
all of the foils look like the witness’s
initial description of the perpetrator.
Eyewitness Testimony

Instructions given to eyewitnesses
are also important.

Identifications are most accurate when
the witness is told that the suspect “may
or may not” be in the lineup.
Eyewitness Testimony

This research has affected U.S.
Department of Justice guidelines for
police to use when questioning
eyewitnesses.
Criminal Defendants

Voluntary False Confessions.

Coerced complaint false confessions


when people are pressured to admit guilt but
privately believe their own innocence.
Coerced internalized false confessions


when people come to believe they committed
crimes they did not commit.
This may occur when the behavior seems
plausible and when other people claim they
are guilty.
Criminal Defendants

Lie Detection

Observers do not detect lies at much
better than chance rates



Despite nonverbal leakage
Law enforcement professionals are generally
not more accurate
There is no correlation between how well
people believe they detect lies and how well
they actually do
Criminal Defendants

Polygraph (“lie detector”) tests



ask suspects to answer questions while hooked
to a machine that records physiological
responses.
The control question test asks about the
critical, as well as about unrelated, wrongdoings.
The accuracy of polygraph tests is debated

advocates claim 90% accuracy, while published
research estimates 57-76% accuracy, not much
better than chance (50%).
Criminal Defendants

How do characteristics of defendants
influence the decisions made by juries?


Physically attractive defendants are less likely
to be found guilty.
Black defendants receive disproportionately
harsher sentences than whites.

This result is found in archival studies while the
results of lab studies are inconsistent.
Criminal Defendants

Aversive racism theory

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People should suppress racist thoughts when
race is salient
Race may have an effect when people are
unaware that it may have one.
Race may have an effect when people’s behavior
can be justified by factors other than race.
According to this theory, jurors would be more
likely to discriminate in trials where the race of
the defendant is not made salient.
Criminal Defendants

Sommers and Ellsworth (2000, 2001)



Participants read about a white or black
defendant who slapped his girlfriend in public.
Half read that the defendant said, “You know
better than to talk that way about a man in
front of his friends.” The other half read the
same sentence with the words “white man” or
“black man.”
In the first condition (race not salient), white
participants made harsher judgments against
the black than against the white; there was no
difference in the race-salient condition.
Juries

Jury Selection

The voir dire process allows judges and
lawyers to question prospective jurors


Goal is to assess the presence of biases that
would interfere with their ability to render a
fair judgment.
Peremptory challenges allow attorneys to
eliminate jurors for a number of reasons

E.g., occupation or personality traits (but
not race or gender)
Juries

Demographic factors are not always
predictive of verdicts

this is most likely when group
membership is relevant to the case
Juries


Jurors who are high in
authoritarianism are more likely to
convict.
“Death qualified” juries are more
likely to convict.
Juries



According to Hastie and Pennington’s story
model of jury decision making, jurors use
the evidence presented in trials to create
stories about the events in question.
Multiple competing stories may be created
The story that best fits the evidence
determines the verdict chosen.
Juries

Comprehension of Judicial Instructions

Juries may have problems understanding
and applying legal instructions.

On-going research is looking for solutions, for
example, rewriting instructions in more “userfriendly” language and allowing jurors to take
notes.
Juries

Jury Deliberations


Twelve-person juries are more
representative and spend more time
deliberating than six-person juries.
Juries using a unanimous decision rule
discuss the evidence longer and more
thoroughly than juries using a majority
decision rule.
Expert Testimony

Psychologists are increasingly asked
to give expert testimony in court
cases.

Judges must consider the scientific
reliability of the evidence, but may lack
the necessary background to rule
effectively.
Expert Testimony

Expert testimony that draws links
between the research and the
particular case has larger influence
on jurors than research that just
presents the research findings.