The Capital Murder Trial
Many researchers have explored how the unique fea-
tures of capital murder trials affect guilt and sentenc-
ing. One such unique feature is the death qualification
process. During jury selection, potential jurors in cap-
ital cases are asked whether they would be willing to
consider imposing a sentence of death if the defendant
is eventually found guilty of capital murder. Prospective
jurors who say they would be unwilling to vote for a
sentence of death are not permitted to serve on capital
juries. Research has shown that the process of death
qualification results in a less demographically repre-
sentative jury (e.g., fewer females and fewer non-
White jurors) as well as a jury that is more receptive to
the prosecution and more likely to impose a sentence
of death. A second distinctive feature of capital trials
concerns the penalty phase instructions to jurors. In
most states, jurors are instructed to weigh or balance
aggravating factors that support a sentence of death
against mitigating factors that support a sentence of
life. Based on postverdict interviews with hundreds of
capital jurors, the Capital Jury Project has found that
jurors have great difficulty in understanding both the
concept of “mitigation” and the concept of “weigh-
ing.” In addition, many jurors often wrongly assume
that unless they vote for a death sentence, the defen-
dant will be eligible for parole and may eventually be
released from prison. Like the death qualification
process, the ambiguity of penalty phase instructions
tends to increase the probability of a death sentence.Deterrence
Deterrence—the theory that the existence of the death
penalty will prevent potential murderers from actually
committing murder—was one the earliest justifications
for executing criminals. Barbarous forms of execution
such as breaking at the wheel, burning at the stake,
decapitation, and disemboweling were thought to be
especially effective at creating the fear necessary to
deter those who might consider committing a capital
crime. Despite the intuitive appeal of this theory,
research does not support a deterrent effect for the
death penalty. The introduction of the death penalty
does not suppress murder rates, and its abolition does
not cause murder rates to rise. Scores of studies have
investigated whether capital punishment has a deter-
rent effect. These studies have looked at homicide rates
in jurisdictions with and without the death penalty(e.g., adjacent states) or examined homicide rates over
time when the death penalty is abandoned or rein-
stated. In examining the possibility of a deterrence
effect, social scientists have attempted to control statis-
tically for factors that are known to contribute to rates
of violence—for example, size of the police force,
number of young males in the population, and unem-
ployment rates. Specific analyses have also been con-
ducted to determine whether only crimes punishable
by death (e.g., aggravated murder) are deterred, and
studies have been conducted to determine whether it is
the actual number of executions (as opposed to
whether the death penalty is an available punishment)
that deters. The overall finding of more than 40 years
of research is that the death penalty does not deter
murderers. Although some researchers have found a
deterrent effect for some jurisdictions over a specific
period of time, other researchers have found what has
been called the “brutalization effect”—a small but
consistent increase in the number of murders in the
weeks following an execution.
Research on deterrence tends to rely on large data
sets collected over long periods of time. But the theory
of deterrence also relies on a psychological explanation
of what happens in the minds of potential killers. For
capital punishment to effectively deter, potential mur-
derers would need to believe that there is a high proba-
bility of being caught, convicted, sentenced to death,
and eventually executed for their crimes. And if the
availability of the death penalty is to have a deterrent
effect beyond that provided by life in prison, the poten-
tial killer would also need to judge the possibility of
eventual execution as substantially more frightening
than the prospect of spending the rest of his or her life
in prison. Even a rational analysis of these probabilities
would not necessarily deter a potential killer, and
because most murders are committed under the influ-
ence of drugs or powerful emotions, it seems implausi-
ble that murderers rationally weigh out alternatives.Public Opinion
Media coverage often emphasizes that a majority of
Americans support capital punishment. It is true that
when Americans are asked the general question, “Do
you favor or oppose the death penalty for persons con-
victed of murder?” approximately 66% of respondents
indicate their support. This support has fluctuated over
time. In 1966, support for capital punishment dropped
to 42%, but by 1988, support had risen to 79% of the188 ———Death PenaltyD-Cutler (Encyc)-45463.qxd 11/18/2007 12:41 PM Page 188