News from
PRINCETON UNIVERSITY
Communications and Publications, Stanhope Hall
Princeton, New Jersey 08544
Tel 609/258-3601; Fax 609/258-1301
FOR IMMEDIATE RELEASE
November 2, 1995
Contact: Mary Caffrey 609/258-5748
Princeton Researchers Find
Factors That Sway Jurors in
Product Liability Trials
When complex scientific or technological testimony is presented in
a courtroom, jurors are likely to be influenced by a variety of
``peripheral'' factors, according to research led by Professor of
Psychology Joel Cooper and funded by the National Science
Foundation (NSF).
As the role of technology in society expands, juries are
increasingly asked to evaluate testimony from science and
technology experts. This is particularly true in civil suits
concerning product liability or personal injury, which were the
focus of the Princeton studies.
This type of testimony is often complex, and in an adversarial
context it is often contradictory. ``Nonetheless, jurors and other
decision makers must arrive at a decision--one that hopefully is
consistent with the evidence presented,'' Cooper writes in the
report that summarizes the studies.
In October 1993, Cooper's team began a series of studies that
examined the influence of scientific and technological testimony
in courts. Working with Cooper were Joan Hall, a lawyer and senior
research assistant in the Department of Psychology, graduate
students Elizabeth Bennett *95 and Holly Sukel, now in her fourth
year of study, and an undergraduate, Isaac Neuhaus `95.
To begin the project, Cooper and Hall recruited focus groups of
industry leaders, litigation and patent attorneys, and experts
from different scientific and technological fields. Groups of five
to 10 people discussed their concerns about presenting scientific
testimony in ways that juries can comprehend.
During this process industry executives and their attorneys
acknowledged that the prospect of being sued sometimes makes them
advise against bringing a product to market, even if they believe
they have science on their side. Solid technological evidence that
a product is safe might not be enough, Cooper wrote, because
``attorneys agreed that it was often difficult to get decision
makers to attend to the scientific and technological evidence
compared to other, often irrelevant cues.''
Used focus groups
In the first two studies, the researchers invited community
members to take part in mock trials featuring videotaped testimony
based on actual cases. Based on the results of the earlier
interviews, the Cooper team wanted to test several ``peripheral
factors'' that they suspected might influence a jury: the
complexity of the testimony, a witness' credentials and the amount
a witness is paid.
A third study asked community members to read an information
packet about an actual personal injury case in which the plaintiff
was injured in an automobile accident. In this study, Cooper and
Hall tested juror bias, including whether jurors react differently
if the defendant is an individual rather than a corporation.
1. Complexity and credentials. Under Cooper's direction, Bennett
and Sukel paid 54 people to view one of four versions of a
``trial'' that dealt with exposure to toxic substances. Groups of
up to eight ``jurors'' watched videotapes in which actors
portrayed witnesses, lawyers and a judge. (The ``jurors'' were not
told that the participants were actors until the study was
finished.)
In all four videos, the facts were the same. The testimony was
manipulated in two ways: Two versions featured testimony in plain
language, while two others contained testimony full of complex
scientific jargon; and the credentials of the plaintiff's chief
witness varied.
The team found that when the testimony was complex, the same
testimony was more influential when delivered by an expert with
high credentials from a prestigious institution than when it was
delivered by an expert whose credentials were more modest.
2. The ``hired gun.'' Neuhaus discussed the results of a second
study in his undergraduate thesis. Cooper and Neuhaus adapted the
``case'' from the earlier study; this time, they altered the
credentials of the expert witness and the amount he was paid -
either $75 or $4,800.
When a witness was well paid, jurors assumed that the witness
testified frequently for high fees. ``Although nothing was
mentioned about the frequency of testifying in court, subjects
formed the judgment that the low paid experts and the highly paid
expert with moderate credentials had appeared an average of about
two times prior to the current testimony,'' Cooper wrote in his
summary report. ``However, they estimated the highly paid expert
with the impressive credentials had testified approximately 14
times in the past.''
Jurors didn't like that, Hall said. ``Perhaps jurors feel that the
highly paid and high-credentialed expert uses his or her position
to make money and thus, may not be totally trustworthy.'' In his
thesis, Neuhaus wrote: ``When an expert receives a large fee, the
juror immediately questions his motives and honesty.''
3. ``Deep pockets.'' In a third experiment, Hall tested juror bias
in favor of the plaintiffs: Does the perception that a defendant
can afford to pay a large award - the so-called ``deep pockets''
effect - sway jurors when a corporation is sued?
This experiment used a personal injury scenario in which the
plaintiff sought compensation for injuries in an automobile
accident. Hall offered groups of ``jurors'' two types of
defendant: an individual and a corporation. She used versions of
testimony that featured equally persuasive witnesses, as well as a
control script skewed in favor of the defendant. Hall also gave
some jurors testimony from a court-appointed expert to gauge
whether this apparently impartial observer would affect a ruling.
Hall found that jurors were more likely to find the defendant
liable if the defendant was a corporation rather than an
individual. In fact, jurors ruled in the plaintiff's favor in all
scenarios except two: An individual defendant could win if the
evidence was clearly in his favor or if he had support from the
court-appointed expert.
``Even when the (scientific) evidence clearly favored the
corporation, and even when a court-appointed expert agreed with
the corporation's expert, there was a significant tendency for
subjects to decide in favor of the plaintiff,'' the report states.
Yet, Hall questioned whether the deep pockets bias is entirely
related to money. The amount of the awards were not greatly
increased if the defendant was a corporation rather than an
individual. It is possible that jurors identify with an individual
but not with an impersonal corporation, Hall said. This question
will be the subject of another study.
Preliminary results from this last study show that testimony from
a court-appointed expert can influence a juror, but the expert's
word does not automatically override other factors, particularly a
juror's own encounters with the medical system. Hall said this
finding could have implications for the voir dire process, which
is under review in New Jersey. A judge may ask prospective jurors
if they have been injured, Hall said, but that question may not
weed out biased jurors. ``It may be a friend's injury that
influences them,'' she said.
Importance to industry, courts
The findings of this research have important implications for the
U.S. legal system, said Hall. ``Expert witnesses are used in 86
percent of civil cases, with an average of four experts in every
trial, and sometimes they contradict each other. We know that
peripheral factors influence jurors--sometimes more than facts and
testimony. What we need to ask is what this means to the future of
our legal system in an increasingly technological age.''
According to William Butz, NSF division director for social,
behavioral and economic research, the findings also have
implications for new technologies in this country. ``U.S. industry
may be less likely to develop or market major innovations, because
of the risk that they may not be able to convince juries with
expert testimony'' if problems occur, he said.
The NSF announced the results of the studies earlier this month,
and officials say that several judges in New Jersey and New York
state have requested copies of Cooper's report.
Cooper is on leave for the 1995-96 academic year, in Australia
writing a book on ``The Psychology of Computer Motivation.''