Reaching a Verdict
Persuading a Jury –
Effect of order of
testimony
Objectives
1.
2.
3.
To understand the basic background of how
a case is presented
To describe and evaluate evidence on the
importance of order of testimony.
To describe and evaluate the key study for
persuading a jury by Pennington and Hastie
(1988).
Background – The Courtroom
Background
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adversarial system
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inquisitorial system
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voire dire
- In the UK they have this. two sides
argue the case in front of a judge and
jury). The jurors have the final decision,
but the judge has to make sure that there
is a fair fight and that one side does not
get an advantage over the other
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In France they have this system. Where
clients are still represented by solicitors,
but a judge calls their own witnesses and
counsel and reaches a judgement
independently.
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In the USA they have this. Where a juror
is interviewed about their fitness to be a
juror and if they hold any preconceived
ideas or attitudes that could bias the trial.
Listen to the following words and
recall them in order
Background - How is a jury selected?
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From the age of 18, you are added to the electoral roll
(computer selection program) and you become eligible for jury
service which normally lasts about 2 weeks. If you are selected,
you will be sent a letter, giving good notice, asking for your
service.
Those who are not eligible: prisoners, ex-prisoners and those
with mental illnesses.
Jurors are unpaid as it is known to be a duty as part of a British
citizen, although expenses are paid.
Jurors must take an oath that they will give their full attention to
the court and that they will make their judgements fairly and
truthfully.
There is a lot of information to absorb over a short period of
time, even in a simple case, and the juror’s task is not easy.
The decision-making process is a lengthy one and they are
aware that their decision will make a significant difference to
that individual, the families involved and society.
Persuading a Jury –
The effect of order of testimony
Is it more effective to present evidence in story order or witness order?
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Psychologists have known for a long time that how we receive information
affects how well we process and remember it.
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Murdoch (1962) – The primacy effect in memory
Using word lists he demonstrated that in serial recall, the first words of a list to
be remembered were always more likely to be recalled than those from the
middle or the end.
Why is this?
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Arousal level at start of task, its novelty, how much effort we put in, our learning
styles and methods.
How does this apply to the courtroom?
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The jury arrive to the court fresh and interested at the start of the case when
the opening statement is presented by the prosecution. Does this mean that the
prosecution has an advantage over the defence at this point?
Persuading a Jury –
The effect of order of testimony
Glanzer and Cunitz (1966)
presented two groups of participants with the same list of words.
- Group 1 – recall immediately
- Group 2 – count backwards as a distraction, then recall
Which group do you think will show better recall?
What does this show and how can it be applied to the courtroom?
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The recency effect is due to short term memory as the most recent words in
the list are recalled. The primacy effect is more due to long term memory as
the words at the beginning of the list are not so recent so have been
remembered.
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When applying this to the courtroom, although the defence closes last…….
Pennington and hastie (1988) Effects of memory
structure on judgement
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To investigate the best ways for cases to be
presented.
Should counsel (i.e. Prosecution or defense
lawyers) take advantage of the primacy and
recency effects and present their best pieces
of evidence/witnesses first and last?
Or should they provide their evidence in a
chronological (story) order?
Persuading a Jury –
The effect of order of testimony
How should the counsel structure their cases?
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Story (chronological) order
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Witness order (primacy and recency effect)
Pennington and Hastie (1982)
Do primacy and recency effects occur in trials?
Study involved a simulated rape trial.
The author rated each witness’s testimony according to how beneficial or damaging
it was to the defendant. Pennington then manipulated the sequence in which both
the prosecution and the defence witnesses were called.
The primacy effect order went from the most beneficial witness first to the most
damaging witness last.
The recency effect order was the opposite of this.
They found that good to bad (primacy) use of witnesses led to the least number
of guilty verdicts. Therefore the primacy effect order reigned supreme.
Pennington and Hastie (1986) – even if evidence is presented in witness order, the jury
will make a chronological story out of it anyway before they reach a decision.
Persuading a Jury –
The effect of order of testimony
Key study
Pennington and Hastie (1988)
Effects of memory structure on judgement
Make notes as we go along!!
Persuading a Jury –
The effect of order of testimony
Aim
Are story order cases true causes of the final
verdict decisions?
What extent does the order of the case affect
the confidence in these final verdict
decisions?
Persuading a Jury –
The effect of order of testimony
Method
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Laboratory experiment
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Independent variable
– story or witness order is manipulated
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Dependent variable
– number of guilty verdicts
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130 participants from Northwestern University and Chicago University were paid for participation
for an hour-long experiment
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These participants were allocated to one of four conditions:
39 prosecution items in story order
39 prosecution items in witness order
39 defence items in story order
39 defence items in witness order.
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In all cases, the stimulus trial began with the indictment and followed the normal procedure,
ending with the judge’s instructions.
Persuading a Jury –
The effect of order of testimony
Method continued..
Procedure
1. Participants listened to a tape recording of the stimulus trial
(Commonwealth of Massachusetts v Caldwell)
2. Then taken to a booth (they were separated by partitions and did not
interact with each other) where they responded to written questions. They
were told to reach either a guilty or not guilty verdict on a murder charge
3. Then asked to rate their confidence in their own decision on a 5-point
scale.
4. In the story order condition, evidence was arranged in its natural order. In
the witness order condition, evidence items were arranged in the order
closest to the original trial.
Persuading a Jury –
The effect of order of testimony
Results
Table to show
percentage of
guilty verdicts
Persuading a Jury –
The effect of order of testimony
Results
What can you draw from this data?
 If you look at each individual case in isolation, you will see that if a
defence case was in story order and a prosecution case was in
witness order, which one had more guilty verdicts?
 Compare this to if it was the other way around and the defence case
was in witness order and the prosecution was in story order? How
many guilty verdicts then?
What does this show?
 If there were more guilty verdicts (in favour of prosecution) in the case
where the prosecution was in story order, this means that the story
order persuaded more jurors.
 Confidence scores were also measured, and the greatest confidence
in their verdict was expressed by those who heard the defence or
prosecution in story order (least confidence in witness order).
Persuading a Jury –
The effect of order of testimony
Discussion/ Evaluation
 Because the primacy and recency effects were controlled for, P&H are
confident that they have shown the persuasive effect of presenting
information in story order.
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But, when data was looked at more closely (see the mean scores)
overall there were more guilty verdicts than not-guilty.
What does this show?
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This shows that the defence cases were not as persuasive as the
prosecution cases, even when presented as a story. However, with
this specific case the defence case was generally less plausible so
cannot be generalised to defence cases in general.
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Ecological validity? – adapted from a real life case - Consequences?
Persuading a Jury –
The effect of order of testimony
More evaluation
 Devine and Ostrom (1985) found greater
discounting of an inconsistent witness
occurred when evidence was organized in
story order.
 Pennington and Hastie (1992) found stronger
and more confident decisions when evidence
was organised in story order.
Pennington and hastie (1988) Effects of memory
structure on judgement
Evaluation
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Does the study have ecological validity?
How useful is it?
How reductionist is it?
How deterministic is it?
Consider both sides of the argument and use
evidence for your answers.