instructions in reducing the prejudicial effects of join-
der on juror decisions.D. David Barnard and Margaret Bull KoveraSee alsoJuries and Judges’ InstructionsFurther Readings
Greene, E., & Loftus, E. I. (1985). When crimes are joined at
trial. Law and Human Behavior, 9,193–207.
Horowitz, I. A., & Bordens, K. S. (1985). Joinder of criminal
offenses: A review of the legal and psychological
literature. Law and Human Behavior, 9,339–353.
Tanford, S., & Penrod, S. (1984). Social inference processing
in juror judgments of multiple-offence trials. Journal of
Personality and Social Psychology, 47,749–765.
Tanford, S., Penrod, S., & Collins, R. (1985). Decision
making in joined criminal trials: The influence of change
similarity, evidence similarity, and limiting instructions.
Law and Human Behavior, 9,319–337.JURIES AND JUDGES’ INSTRUCTIONS
When a jury trial is conducted, community members
who typically have no special legal training or knowl-
edge are called on to serve as jurors. During the trial, the
judge instructs jurors as to the relevant law and the pro-
cedures to be used to determine an appropriate verdict in
the case. Unfortunately, jurors do not always render a
verdict congruent with the law. Frequently, jurors mis-
understand a large portion of the instructions that are
presented to them. In some cases, jurors may also decide
to disregard the instructions they have been given. A
variety of factors contribute to instruction ineffective-
ness, including the language used to convey the instruc-
tions, jurors’ education level, and jurors’ preexisting
“commonsense” beliefs about the law. A number of pro-
posed improvements to the instruction process, such as
rewriting the instructions, changing the timing of deliv-
ery of instructions, providing written instructions, and
providing a special verdict form or flow chart/decision
tree, have been empirically evaluated. The effectiveness
of each of these potential solutions is discussed.Purpose of Instructions
During a trial, the judge delivers relevant substantive
and procedural instructions to jurors. Substantiveinstructions refer to laws that apply to the specific case
at hand (e.g., the definition of first- and second-degree
murder, manslaughter, sexual assault, and arson; rele-
vant civil laws, etc.). Procedural instructions refer to
the general duties of jurors and are relevant across
cases (e.g., legal thresholds such as “reasonable doubt”
in criminal cases or “clear and convincing evidence” in
most civil cases in the United States, the decision rule
to be used—either a unanimous or a majority decision,
concepts such as burden of proof, etc.).Development of Pattern Instructions
Historically in the United States, judges would create
jury instructions on a case-by-case basis with input
from the attorneys involved in the case. However, this
process was time-consuming and led to frequent objec-
tions on the ground that the relevant law had been
incorrectly explained to jurors. In addition, there was
not always consistency in the instructions used in cases
of a similar nature. Finally, there was concern that
jurors did not understand the instructions they were
presented with due to the complexity of the law and
because judges were forced to focus their attention on
delivering instructions that were legally accurate rather
than on explaining the law in a manner that jurors could
easily understand, to avoid having cases appealed.
To resolve these problems, prewritten “pattern jury
instructions” were developed. Pattern instructions are
instructions that have been preapproved by relevant
sources (legislatures, state bars, commissions) and can
be used repeatedly. In 1938, California was the first
state to adopt a set of pattern instructions. This prac-
tice quickly spread to jurisdictions across the United
States at both the state and the federal level.
Pattern instructions were efficient for judges to use,
reduced the number of appeals due to the use of erro-
neous instructions, and successfully ensured that
jurors in similar cases heard consistent instructions.
However, a well-established body of social science
research has demonstrated that jurors still have con-
siderable difficulty in understanding the law when
pattern instructions are used.Jury Instruction Comprehension Rates
Instruction comprehension problems have been found in
jurisdictions throughout the United States and in other
countries that use laypersons as jurors (e.g., Canada,
New Zealand, Australia, Scotland, and England). ManyJuries and Judges’ Instructions——— 395J-Cutler (Encyc)-45463.qxd 11/18/2007 12:43 PM Page 395