Chapter 12
Law
The Social Psychology of Evidence
Overview of the American Criminal
Justice System
Eyewitness Testimony
• How accurate are eyewitness accounts?
• Three conclusions about eyewitness
testimony:
– Eyewitnesses are imperfect.
– Certain personal and situational factors
systematically influence eyewitness’ performance.
– Judges, juries, and lawyers are not well informed
about these factors.
Eyewitness Testimony: Acquisition
• Refers to the witness’s perceptions at the time
of the event in question.
• Factors influencing acquisition:
– One’s emotional state
– Weapon-focus effect
– Cross-race identification bias
Eyewitness Testimony: Storage
• Refers to getting the information into memory
to avoid forgetting.
• Memory for faces and events tends to decline
over time.
• But, not all memories fade over time.
– However, the “purity” of the memory can be
influenced by postevent information.
Eyewitness Testimony: Storage (cont.)
• Misinformation Effect: The tendency for false
postevent information to become integrated
into people’s memory of an event.
• If adults can be misled by postevent
information, what about children?
– Repetition, misinformation, and leading questions
can bias a child’s report, particularly for
preschoolers.
Biasing Eyewitness Reports With
Loaded Questions
Eyewitness Testimony: Retrieval
• Refers to pulling the information out of
storage when needed.
• Factors affecting identification performance:
– Lineup construction
– Lineup instructions to the witness
– Format of the lineup
– Familiarity-induced biases
Courtroom Testimony of Eyewitnesses
• Eyewitness testimony in court is persuasive
and not easy to evaluate.
• Why do jurors often overestimate the
accuracy of eyewitnesses?
– Lack knowledge about human memory.
– Base judgments largely on witness’s confidence.
Morphing Composite Faces to Catch a
Thief
Effects of Lineup and Instructions on
False Identifications
The Biasing Effects of PostIdentification Feedback
Improving Eyewitness Justice
• Educate judges and juries about the science so
they can better evaluate eyewitnesses who
testify in court.
• Make eyewitness identification evidence itself
more accurate.
What Eyewitness Experts Say in Court
What Eyewitness Experts Say in Court
The Psychology of Lie-Detection
• Polygraph: A mechanical instrument that
records physiological arousal from multiple
channels.
• Do the lie-detector tests really work?
– Truthful people often fail the test.
– The test can be faked by artificially inflating
arousal responses to “innocent” questions.
Approaches to Police Interrogations
• Pressure the suspect into submission by
expressing certainty of his or her guilt.
• Befriend the suspect.
The Nine Steps of Interrogation
False Confessions
• May confess merely to escape a bad situation.
• Internalization can lead innocent suspects to
believe they might be guilty of the crime.
• Two factors can increase the risk of false
confessions:
– Lack of a clear memory of the event in question
– Presentation of false evidence
Factors That Produce False Confessions
Do Guilty Expectations Produce False
Confessions?
Confessions and the Jury:
An Attributional Dilemma
• Juries are powerfully influenced by evidence
of a confession, even if the confession was
coerced.
– Fundamental attribution error revisited.
• A jury’s reaction can be influenced by how
confession evidence is presented.
Jury Decision Making
Jury Selection
• Voir dire is the pretrial examination of
prospective jurors by the judge or opposing
lawyers to uncover signs of bias.
• A peremptory challenge is a means by which
lawyers can exclude a limited number of
prospective jurors without the judge’s
approval.
Trial Lawyers as Intuitive Psychologists
• As far as trial practice is concerned, how-to
books claim that the astute lawyer can predict
a juror’s verdict by his or her gender, race,
age, ethnic background, and other simple
demographics.
Scientific Jury Selection
• A method of selecting juries through surveys
that yield correlations between demographics
and trial-relevant attitudes.
• Does scientific jury selection work?
• Is scientific jury selection ethical?
Juries in Black and White: Does Race
Matter?
• To what extent does a juror’s race color his or
her decision making? Research suggests that
there is no simple answer to this question.
Effects of Racial Diversity on the Jury
Death Qualification
• A jury selection procedure used in capital
cases that permits judges to exclude
prospective jurors who say they would not
vote for the death penalty.
• Are death-qualified juries prone to convict?
The Courtroom Trial
Nonevidentiary Influences:
Pretrial Publicity
• Does exposure to pretrial news stories corrupt
prospective jurors?
• Why is pretrial publicity potentially
dangerous?
– Often divulges information that is not later
allowed into the trial record
– Issue of timing
Contaminating Effects of Pretrial Publicity
Nonevidentiary Influences:
Inadmissible Testimony
• Why do people not always follow a judge’s
order to disregard inadmissible evidence?
– Added instruction draws attention to the
information in controversy.
– Judge’s instruction to disregard may arouse
reactance.
– Jurors want to reach the right decision, so it is
hard to ignore information that seems relevant to
the case.
Nonevidentiary Influences:
The Judge’s Instructions
• To make verdicts adhere to the law, juries are
supposed to comply with the judge’s
instructions.
• Do jurors understand their instructions?
• What about the timing of the instructions?
• What if the jury disagrees with the law?
– Jury nullification
Jury Deliberation
Leadership in the Jury Room
• A person is more likely to be chosen as
foreperson if the person:
– Is of higher occupational status or has prior jury
experience
– Is a male
– Is the first person who speaks
– Is sitting at the head of a rectangular table
• Forepersons act more as the jury’s moderator
rather than its leader.
The Dynamics of Deliberation
• In criminal trials, deliberation tends to
produce a leniency bias favoring the
defendant.
– leniency bias is the tendency for jury deliberation
to produce a tilt toward acquittal.
• How do juries resolve disagreements?
– A combination of informational and normative
influence
Jury Deliberations: The Process
The Road to Agreement: From
Individual Votes to a Group Verdict
Jury Size
• How does jury size affect the decision-making
process?
– Possible lack of allies in smaller juries may make it
harder to resist normative pressures.
– Smaller juries are less likely to represent minority
segments of the population.
– Smaller juries are more likely to reach unanimous
decisions after shorter deliberation periods.
Less-Than-Unanimous Verdicts
• Weakens jurors who are in the voting
minority.
• Breeds closed-mindedness.
• Short-circuits the discussion.
• Leaves many jurors uncertain about the
decision.
Posttrial
To Prison and Beyond
The Sentencing Process
• People disagree on the goals served by
imprisonment.
– Incapacitate offenders and deter them from
committing future crimes?
– Exact retribution for misdeeds?
• Common public complaint is sentencing
disparity.
– Sentencing disparity is the inconsistency of
sentences for the same offense from one judge to
another.
The Prison Experience
• Does the prison situation lead guards and
prisoners to behave as they do?
• Zimbardo et al.’s (1973) Stanford Prison Study.
• How does this study inform the power of the
situation?
Perceptions of Justice
Justice as a Matter of Procedure
• Satisfaction with dispute resolution depends
on both the outcome and the procedure used
to achieve those outcomes.
• Important aspects of procedure:
– Decision control
– Process control
Which Legal System Do People Prefer?
• Adversarial Model: The prosecution and
defense present opposing sides of the story.
• Inquisitorial Model: A neutral investigator
gathers evidence from both sides and presents
the findings in court.
• Adversarial proceedings seen as more fair and
just because the method offers participants a
voice in the proceedings.
Culture, Law, and Justice
• Much of research from this chapter can be
universally applied
– Yet there are important cross-cultural differences
• Different nations have different laws
• Different cultures have different customs
• Likewise, punishments for crimes also vary
Closing Statement
Closing Statement
• Through an understanding of social
psychology we can now identify the problems
in the legal system and even find some
solutions.