Chapter 1: Psychology and The Law
Canadian Justice System consists of:
civil law - one party (the plaintiff) brings a complaint against another (the
defendant) for violating the former's right in some way.
criminal law - when police arrest a suspect and a judge decides whether there is
enough evidence to press formal charges. (sometimes at a preliminary hearing, a
judge decides whether there will be a trial).
- In criminal cases, first impression of the accused and of witnesses have a
powerful effect on police investigators and jurors (primacy effect). Attributions
about what causes the criminal behaviour are made by police, lawyers, jurors,
and the judge; prejudice beliefs and stereotypical ways of thinking affect those
- most common cause of an innocent person's being convicted of a crime is an
- jurors rely heavily on eyewitness testimony when they are deciding whether
someone is guilty. Unfortunately, jurors also tend to overestimate the accuracy of
- experiment "staged calculator theft" :
the first set of results reflected what we'd expect: The more visual information
available about the their, the higher the percentage of students who correctly
identified him in the photo lineup. The jurors overestimated the accuracy of the
witnesses, especially in the condition in which the thief was difficult to identify.
-In 36 of 40 of these cases, an eyewitness had falsely identified the suspect as
the criminal; five of these falsely accused people were on death row when they
were exonerated. (DNA evidence proved the suspect was innocent after he/she
Why are eyewitnesses often wrong:
3 stages of memory (Acquisition, Storage and Retrieval):
acquisition: the process by which people notice and pay attention to information
in the environment; people cannot perceive everything that is happening around
them, so they acquire only a subset of the information available in the
environment. Sources of error:
- poor viewing conditions
- people see what they expect to see
- focus on weapons
- own-race bias
- change blindness
- a number of factors limit the amount of information about a crime that people
take in, such as how much time they have to watch an event and the nature of
the viewing condition. Crimes usually occur under the very conditions that make
acquisition difficult: quickly, unexpectedly, and under poor viewing conditions
such as at night.
- "julia robert's photograph experiment" - they found that accuracy in identifying
the celebrities began to drop when the simulated distance exceed 7.5 meters. At
10 meters only 75 percent of the participants recognized the face, and at 23
metres, only 25 percent of the participants did.
- we should also remember that eyewitnesses who are victims of a crime will be
terribly afraid, making it difficult to to take everything in. The more stress people
are under, the worse their memory for people involved in and the details of a
crime. Another resin why they have poor memory for a suspect is that they tend
to focus their attention on any weapon they see and less on the suspect's
- information people notice and pay attention to is also influenced by what they
expect to see. - for example; the case of the old lady next door who was
strangled (pg. 8)
own-race bias: the finding that people are better at recognizing faces within their
own race than those of other races
- What about the Koreans who grew up in white families? They had better
memory for white faces, which is consistent with the idea that we are best at
remembering faces that are of the race with which we have the most contact.
- unfamiliar events or people are also more difficult to remember than familiar
events of people.
- when people examine same-race faces, they pay close attention to
individuating features that distinguish that face from others, such as the height of
the cheekbones or the contour of the forehead. They do not do this for other
races unless told to. Storage: the process by which people store in memory information they have
acquired from the environment
Sources of error:
- misleading questions
- source monitoring errors
- only 48 percent of the bystanders and 38 percent of the victims correctly
remembered the suspect's had colour. They could only pick the criminal out of a
lineup 48 percent of the time.
reconstructive memory: the process by which memories of an event become
distorted by information encounter after the event occurred.
- when participants were again questions about the crimes, those who had been
exposed to misinformation were more likely to have incorporated it into their
memory of the event.
- people are especially likely to incorporate misinformation in their memories
when the event they have witnesses produces negative emotion - which is likely
in crimes. Adults with intellectual disabilities may be especially vulnerable to
being swayed by leading questions.
source monitoring: the process by which people try to identify the sources of
Retrieval: the process by which people recall information stored in their memory.
- research shows that if a witness selects a suspect from a lineup, jurors, police,
investigators and judges are likely to assume that the witness is right.
- lineups have a higher success rate than the alternative of showing eyewitness
only one person. However, if one person was shown and that person was
innocent, a mistaken identification was four times more likely than when the
same person appeared in a six-person lineup. Errors were especially likely if the
innocent person worse clothing similar to that worn by the person who committed
- witnesses often choose the person in a lineup who most resembles the criminal,
even if the resemblance is not strong.
To avoid errors police follow these steps:
- ensure that everyone in the lineup resembles the witness's description of the suspect
- tell the witnesses that the person suspected of the crime may or may not be in
- do not always include the suspect in an initial lineup
- make sure that the person conducting the lineup does not know which person in
the lineup is the suspect
- present pictures of people sequentially instead of simultaneously
- present witnesses with photographs of people and sound recordings of their
- don't use composite face programs (where witnesses generate faces)
- try to minimize the time between the crime and the identification of suspects
Judging Whether Eyewitnesses are Mistaken:
Does Certainty Mean Accuracy?
- A witness's confidence is not strongly related to his or her accuracy. For
example with the calculator theft experiment, witnesses who saw the crime under
poor viewing conditions had as much confidence in their identifications as did
witnesses who saw the crime under moderate or good viewing conditions, even
though the former were considerably less accurate.
- Jurors are also more likely to believe a confident, rather than unconfident,
witnesses - a disturbing finding after obtaining this research
Sings of Accurate Testimony
- accurate witnesses in a photos lineup tended to say that they didn't really know
how they recognized the man, that his face just "popped out" at them. Inaccurate
witnesses tended to say that they used a process of elimination whereby they
deliberately compared one face with another. Ironically, taking more time and
thinking more carefully about the pictures was associated with making more
- people are most accurate she they made their judgement quickly - in 10
seconds or less.
The Problem with Verbalization:
- It would seem that another way to improve accuracy of eyewitness identification
would be to tell people to write down a description of the suspect as soon as they
can, to help them remember what they say. However, trying to put an image of a
face into words can make people's memory worse!
- in the bank robbery experiment, 38 percent of the people in the verbalization
condition correctly identified the robber, compared with 64 percent of the people
in the non-verbalization condition. Judging Whether Eyewitnesses are Lying
- some witnesses might deliberately lie (for example if a reward is involved)
- people are better than chance at telling lies from truth, but their level of
accuracy is not impressive: On average, people were correct only 54 percent of
the time. Accuracy rates are even lower when people try to detect deception in
members of other ethnic groups.
- confidence that you have correctly identified the lies and truths is not strongly
correlate with accuracy as well
- people with a lot of experience dealing with liars (custom officers, detectives,
judges) are no more accurate at detecting deception that are university students.
polygraph: a machine that measures people physiological responses (e.g. heart
rate); polygraph operators attempt to tell if someone is lying by observing how
that person responds physiologically while answering the questions.
- accuracy rate for these machines was 0.86. Because there is still a chance
these machines can make a mistake (14% chance) the Canadian justice system
does not allow the results of polygraph evidence to be used in court.
- researches continue to try to develop better lie detectors, using measures such
as patterns of brain waves, involuntary eye movements, and blood flow in the
face by using high-definition thermal imagining technology.
- there is some evidence that people can deliberately act in ways that reduce the
validity of the results of polygraph tests, such as biting their tongue and doing
Can Eyewitness Testimony Be Improved?
- there is no hard evidence that people's memories improve when they are
hypnotized. In fact, there is some evidence that when people are under hypnosis
they are more susceptible to suggestion, coming to believe they saw things that
they did not. Even worse, people tend to become more confident in their
memories after they have been hypnotized, even if they are no more accurate.
witness testimony that has been obtained under hypnosis is not admissible in the
cognitive interview: A technique in which a trained interview tries to
improve eye-witnesses' memories by focusing their attention on the details and context of the event.
- this is done chiefly by asking the person to recall the event several times from
different starting points (e.g. from the beginning or the middle) and by asking the
person to create a mental image of the scene.
- research found that children had better memories for activities that they had
engaged in over a two-week period when they were asked to mentally "return to
the scene". Other claim that the cognitive interview may in fact, increase errors
and confabulations of memory especially when used with children.
- reinstating the context (returning to the same room where the crime occurred)
had some positive effects (e.g. better memory for what had happened) but also
some negative effects (e.g. being more willing to identify someone from a lineup,
regardless of accuracy).
- According to leading expert Gary Wells (assisted in developing a National
Institute of Justice guide for law enforcement on eye witnesses), the most
effective approach for reducing the rate of false convictions in the legal system is
to improve how police conduct eyewitness interviews and identification
procedures. Recommendations include avoiding leading or suggestive questions
when interviewing witnesses, telling witnesses that the suspect may or may not
be in the lineup, and so on.
The Recovered Memory Debate:
recovered memories: recollections of an event, such as sexual abuse that
have been forgotten or repressed
- the accuracy of these memories have been hotly debated. On one side, two
woman writers claim that it is not uncommon for women who were sexually
abused to repress these traumas so that they have absolutely no memory of
them. THe abuse and its subsequent repression, according to this view, are
responsible for many psychological problems,such as depression and eating
disorders. and later in life, often with help of a psychotherapist these events can
- on the other side of the controversy are academic psychologist who argue that
the accuracy of recovered memories cannot be accepted on faith.
false memory syndrome: remembering a past traumatic experience that is
objectively false but nevertheless accepted as true
How do we know whether these recovered memories are true or not? - descriptions of fabricated traumatic events contained fewer specific details
about time and place than did descriptions of actual traumas and were rated as
less believed by coders (didn't know which one was true or not).
- participants reported stronger emotional reactions to the fabricated traumas
than to the actual traumas - even though when describing these events,
fabricated accounts actually were less emotional than accounts of actual
traumas. This tendency to "go over the top" when reporting on reactions to
fabricated traumas was also reflected in participants' reports of how much they
thought about the event, their level of traumatic stress, and their experience of
post-traumatic stress disorder symptoms.- all of these reactions were reported
more strongly when describing a fake, rather than a real, traumatic event.
- people who were fabricating remorse were more likely to show more extreme
emotional displays. They also exhibited more speech hesitations and de more
references to other people than those who were expressing genuine remorse.
Other kind of Evidence Expert Testimony
• Expert testimony has an effect on juror’s verdictsparticipants
who received expert testimony in the mock juror were more likely to
conclude that the woman acted out of self-defense when she murdered
her husband (because she was suffering from battered wife syndrome),
rather than when they had not received expert testimony.
• Opinions on whether expert testimony should be used in
courts vary (psychologists believe their opinions are highly useful however
some judges believe that what they have to offer is common sense)
• Examples such as footprints, fingerprints, samples of hair
and fibres and DNA
• Although DNA testing is more conclusive than many other
kinds of evidence, jurors may be quick to convict based on DNA evidence,
without fully understanding its limitations.
• Other types of physical evidence tend not to be very
persuasivephysical evidence alone is not very convincing
• According to civil law, companies should be responsible if it
“is more likely than not” to have been responsible (example in textbook: a
bus hits and kills a dog but it is not known which bus company the bus
belongs to. However 80% of the buses in that route belong to the Blue
Bus company therefore they should be held responsible).
• In mock cases using this example, participants were much
more swayed by eyewitness testimony (being told that the bus they had
seen was a Blue Bus) than by statistical evidence (that 80% of the buses
on that route were from Blue Bus) Juries
• Trial by jury was an established institution in England at the
beginning of the 17 century and was adopted by Canada in 1867
• Jury system has often come under attack because of many
wrongful convictions and the argument that jurors may lack the ability to
understand complex evidence and reach a dispassionate verdict.
How Jurors process information during the Trial
• Some psychologists argue that jurors decide on one story
that best explains all of the evidence, then they try to fit this story to the
possible verdicts they are allowed to render
Lawyers typically present the evidence in one of two ways:
• Story order: they present the evidence in the sequence in
which events occurred, corresponding as closely as possible to the story
they want the jurors to believe
• Witness order: they present witnesses in the sequence they
think will have the greatest impact even if this means that event are
described out of order (ex: leaving the best witness for last so the trial
ends on a dramatic note)
*When prosecutors used the story order and the defense used the witness order,
te jurors were most likely to believe the prosecutor
*When the prosecutor used the witness order and the defense used the story
order, the tables were turned and the jurors were more likely to believe the
Confessions are not always what they seemthe interrogation process can go
wrong n ways that elicit false confessions, even to the point where innocent
suspects come to believe that they actually did commit the crime
• The greater the use of influence tactics and coercive tactics,
the higher the rate of confession
• “Mr. Big” Technique: tends to be used in serious criminal
cases and involves undercover officers enticing the suspect to commit
small crimes in exchange for money and the promise of gang
membership. At some point the suspect is told that he will be meeting the
head of the gang or organization and reasons will be given for why the
suspect needs to “come clean” before he can be accepted into the
gangsometimes the suspect will be told that police have evidence that he
is guilty of the crime and this produces high rates of confessions
• offenders who believed that the police had strong evidence
against them were more likely to confess than those who believed that the
evidence was weak
• in Canada interrogations and confessions are usually
recorded so that the jury can judge for themselves whether the defendant was coerced into admitting something
• In recordings, people thought that the confession as most
voluntary (the least coerced) when the camera focused on the suspect
rather than the interrogator-assuming they had more control over the
Deliberations in the Jury Room
• Even if most jurors are inclined to vote to verdict, there might
be a persuasive minority that changes their fellow jurors’ minds.
• However research has f