know that mitigating evidence can include anything
they believe should weigh in favor of a life sentence.
Both aggravating evidence and mitigating evidence
are presented during the penalty phase of a capital trial,
to inform the jury’s life and death decision. Although
most jury instructions refer to these terms, many
instructions do not provide definitions of the terms for
jurors. Similarly, some states provide a list of “factors”
that can be considered in the penalty phase but do not
indicate whether the individual factors should be con-
sidered as aggravating or mitigating. In most jurisdic-
tions, jurors are instructed to “weigh” aggravating and
mitigating evidence in order to decide on the appropri-
ate punishment. However, no specific formula for this
weighing process or information about how it should
take place is provided to jurors.Juror Confusion
Evidence from mock jury studies, case studies, and
interviews with actual jurors in death penalty cases
shows that jurors have a great amount of trouble
understanding these terms and applying the concepts.
In some studies, jurors understood less than half
the instructions they heard. This confusion extends
beyond a failure to understand the words used; it also
affects the ability of jurors to identify whether partic-
ular types of evidence should be used in favor of a life
sentence or a death sentence and their ability to weigh
the evidence presented in a legally appropriate man-
ner. For example, studies have shown that many jurors
believe that they are required to impose a sentence of
death in certain situations, when in fact a death sen-
tence is never required by law.
Many possible explanations for this confusion have
been advanced. For example, some explanations focus
on the use of confusing, passive language and the
excessive use of jargon in the instructions. Others
have suggested that jurors may become confused
because they hold incorrect assumptions about crime
and punishment at the time of the trial and these
assumptions prevent them from understanding the
accurate legal meanings of terms and instructions.
It is significant to note that in addition to the gen-
eral lack of comprehension of instructions in the
penalty phase of capital cases, the confusion does not
seem to be evenly distributed, or to have a neutral
impact. Although jurors have trouble with all these
concepts, they seem to have more trouble understand-
ing the concept of mitigating (the evidence that shouldbe used in support of a life sentence) than aggravating
circumstances. There are several possible explana-
tions for this confusion. For example, in cases where
the terms are not defined, jurors may rely on their per-
sonal knowledge of the terms. Because aggravatingis
a term we use more often than mitigatingin our daily
lives, it may be more familiar to jurors. No matter
what the reason, this confusion means that sometimes
jurors may not recognize mitigating evidence as being
relevant to their decision. At other times, jurors may
mistake mitigating evidence as being aggravating
instead and use it against the defendant (to vote for
death) rather than in his or her favor (by sparing the
defendant’s life). This sort of error, a direct result of
juror confusion, can have significant consequences for
the accuracy of the decision-making process and for
the defendant’s future.Jury Decision Making
This lack of comprehension affects the jury decision-
making process in capital cases in both direct and
indirect ways. For example, as described above,
research suggests that the skewed nature of the con-
fusion may bias jurors toward death, rather than life,
sentences, although the specific impact of juror com-
prehension on verdict choice is currently unclear.
There is also some concern that this bias toward the
death penalty embedded within the jury instructions
works in combination with several other aspects of
the capital-sentencing structure (including the use of
two phases with the same jury for both and the death
qualification process) to make death verdicts even
more likely.
In addition to the direct impacts of juror confusion
on verdict choice, research shows that jurors who are
confused by the instructions will rely instead on the
things they know and understand—if jurors do not
understand the judge’s instructions, they are more
likely to make their decisions based on their personal
schemas and stereotypes. While a juror with a good
understanding of the instructions is likely to base his or
her decision on the relevant evidence and adhere to the
weighing process in a legally appropriate way, the
confused juror’s reliance on stereotypes allows for
bias and prejudice to enter the decision-making
process. Research has shown, for example, that mock
jurors with lower comprehension levels are more
likely to sentence a Black defendant to death than
those with higher comprehension levels. In addition,Jury Understanding of Judges’ Instructions in Capital Cases——— 427J-Cutler (Encyc)-45463.qxd 11/18/2007 12:43 PM Page 427