Social Psychology and the Court of Law

How people’s perceptions, misperceptions, and cognitive biases can affect criminal investigations and court room outcomes.

The legal community understands the importance social psychological factors play -- Many law schools require their students take courses on it.

Social Psychology has examined many areas of legal/social significance:

Accuracy and Persuasiveness of Eyewitness Testimony

Criminal investigation interview techniques

Factors which can affect Police lineups

Jurors ability to follow judges instructions

Defendant Characteristics

Jury size

Eyewitness Testimony

Lab studies have shown that eyewitness testimony can be crucial in criminal cases.

Elizabeth Loftus -- preeminent researcher of eyewitness testimony and repressed memories.

Constructed a hypothetical homicide-burglary scenario:

One group of "jurors" heard only circumstantial evidence which linked the defendant to the crime --- 18% voted to convict

A second group heard the circumstantial evidence and the corroboration of 1 eyewitness --- 72 % voted to convict !

A third group heard the c. e. And the eyewitness, but the eyewitness was discredited (Your blind, it was dark, you were a 1/4 mile away from the defendant). Despite the eyewitness being attacked , 68% still voted to convict !

The bottom line is that criminal cases where an eyewitness is produced is more likely to result in a conviction (Visher, 1987)

If the prosecution produces an eyewitness, the defense needs to both discredit that eyewitness and be able to produce their own eyewitness, in order to minimize the damage to the defendant.

Eyewitness Accuracy

Buckhout (1974) --- Staged a physical-assault on a professor in front of about 140 students at California State University.

6 weeks later, the students were shown photographs of six males, one of which was the assailant. 60 % of the students identified the wrong individual.

Juror’s often focus on the mannerisms, of a witness, so more confident, self-assured witness’s testimony is given more credibility.

However, there is only a small positive correlation between self-confidence and accuracy of report.

Large scale analysis of eyewitness accuracy indicates that eyewitnessess are only about 80% accurate under good circumstances.

People’s memory can often be influenced after the fact

The Misinformation Effect: Questions asked can often contribute to the distortion of a memory.

The Misinformation Effect : (remembering wrong information)

This experiment helps to demonstrate how question wording can affect a persons memory for an event.

Loftus (1978) : Had students view slides of a traffic accident.

One group saw the car parked in front of a stop sign.

The second group saw the car parked in front of a yield sign.

Later, students were asked : Did you see a green car pass in front of the red car while it was at the ( stop or yield) sign ?

Students who saw the "Stop" slide and were asked the question with the word "stop sign" were 75% correct when asked:

Was the car in front of a stop sign ?

Students who saw the "Stop" slide and were asked the question with the word "yield sign" were only 41% correct when asked.

Moreover, the students who were wrong were adamant in their belief that the car was at a yield sign !

Retelling an event can solidify memories, accurate or not.

Attorney’s often have their witnesses go over events repeatedly before trial, helping their witnesses seem more self-confident and assured.

Police interview techniques:

Because the type of questions asked can influence a witnesses subsequent memory for an event, researchers have developed a "cognitive interview technique" for police to use which can help gather more information than "traditional interview" techniques.

Traditionally, police will ask questions which are based on their own pre-existing understanding of the facts -- this can lead to confirmation bias.

Fisher et. Al. (1987) developed an interview technique which produced 50% more information when used by actual police officers.

Fisher’s Guidelines for police interview techniques:

1. Allow people to tell their story uninterrupted.

First, have them recreate the setting, and visualize the scene, showing pictures if necessary.

Prompt them to remember what they were thinking and feeling at the time (mood congruency)

2. After their complete retelling, then attempt to jog

their memory with open-ended questions which do not reveal any additional information which the police may know.

Minimizing False Lineup identifications:

Expectations can affect police lineups

People often will choose a person who is similar to the actual culprit, if the culprit is not in the lineup him/herself.

Having people look at numerous mugshots can reduce accuracy in later identifying a suspect. (Brigham & Cairns, 1988)

How a person looks for a suspect can lead to misidentification:

Witnesses who analytically compare mugshots are less accurate than witnesses who look for a face to just "pop" out of a lineup or photographs.

Eyewitness misidentification can be reduced by having people make "yes/no" judgements to a series of suspects one at a time, rather then showing them all suspects at once.

Misidentification can also be reduced by including instructions that state "the suspect may not be in this lineup, so you are under no pressure to pick out an individual from this lineup"

Because of psychological factors which affect peoples memories, Social Psychologists are often called on as expert witnesses to help educate juries:

Social Psychologists often testify how:

Eyewitnesses often perceive events selectively

Discussion of events after they happen can affect subsequent memory of that event.

Research using staged crimes indicate the fallibility of eyewitnesses

Eyewitnesses are especially prone to error when trying to identify someone of another race.

That eyewitness confidence in not a good indication of eyewitness accuracy.

Experiments have shown that this information can cause juror’s to analyze eyewitness testimony with more skepticism and discuss eyewitness testimony more fully during deliberations.

Defendant’s Characteristics

Researcher’s have studied how physical attractiveness and similarity to the juror’s of a defendant can affect the outcome of a trial.

Researchers give different mock juries the same facts concerning a case and manipulate physical attractiveness and/or similarity of the defendant to the jurors.

Although jurors do not ignore the "facts" of a case when deliberating, when the evidence is ambiguous or lacking, they are more likely to let the personality traits of the defendant influence their decisions.

Berry & McArthur (1988) -- Found that students judged "baby-faced" adults as being more naive and rated them not-guilty of intentional criminal acts more often than "mature-faced" adults

Downs & Lyons (1991) -- Had police escorts rate the physical attractiveness of defendants in over 1500 misdemeanor cases in Texas and then correlated the physical attractiveness with the monetary fines given by the judge.

A strong negative correlation was found between the physical attractiveness and the amount of money the person was fined.

Similarity of the defendant to the jury.

Political Beliefs (Amoto, 1979)

Same Language (Stephan & Stephan, 1986)

Expectations of stereotypical behavior:

Mock jurors punished white defendants more severely for white-collar crimes (embezzlement, fraud) (Mazzella & Feingold, 1994)

Mock jurors punished African-American defendants more harshly for violent crimes. (Sweeny & Haney, 1992).

Despite the cognitive biases of jurors, when the evidence is clear and the jury focuses on that evidence, these biases will have minimal impact on the outcome of a trial

The Judges Influence in the courtroom

Very often, a judge will instruct jurors to ignore a piece of evidence of information during the course of a trial.

However, studies have shown that jurors are often unable to ignore or repress the forbidden testimony, and the fact the judge tells them to ignore it may make it even more salient.

This has lead to "rape-shield" laws, which state the discussion of a rape victims prior sexual history is not admissible.

Pre-trial publicity can also affect the jury, and judges instructions to potential juries to ignore everything they had seen on TV and in print have little impact.

Kramer et. al. (1990) Exposed 800 mock jurors to pre-trial publicity damaging to the defendant (past criminal history)

After jurors saw the videotape of the trial, they either heard the judges instructions to ignore the pre-trial publicity or heard no additional instructions. The same proportion of jurors voted to convict in both instructional groups.

Certain studies have shown that even a judges nonverbal behaviors can be picked up on by juries. (Hart, 1995)

Juries and Justice

Jury comprehension: Due to the intricacies of the legal system, the understanding of the jury with respect to certain legal terms can be quite different from the judges and/or lawyers understanding.

Smith (1991): showed that pretrial training sessions for jurors can make the jury more receptive and understanding of both the judges instructions to them and the precise comprehension of rules of evidence and testimony.

Death Qualified Jurors: In capital punishment cases, jurors who will not support capital punishment are excluded. Attitude surveys of people who do not oppose the death penalty show that they have more interest in crime control than due process of law which might favor criminals.

6 or 12 people on a jury?

The less people who are on a jury, the less deliberation, and less diversity, and less chance of minority influence to reverse the predominant viewpoint of the jury

The Misinformation Effect Experiment (Loftus, 1978)

Students first saw a videotape of a traffic accident.

½ students saw car stop at a STOP sign

½ students saw car stop at a YIELD sign

After viewing the accident tape, students were next asked a series of questions about the accident.

One early (leading) question: Did you see another vehicle pass the car while it was at the (STOP or YIELD) sign

A much later question asked: What type of traffic control sign was the vehicle stopped next to ?

If the videotape and the leading question were both consistent (i.e. saw car next to STOP sign, asked if another vehicle passed the car at the stop sign ). The students were 75% correct when later identifying what type of traffic control sign was present.

If the leading question was inconsistent with the videotape, students were only 41% correct in response to the later question! Moreover, many who supplied wrong answers were highly confident in their responses !