Jurors and alternates in the O. J. Simpson trial are going to have to think their way through months of testimony in order to emerge at the other end of their ordeal with a just verdict.
How well is the jury pool equipped for the job? Not very well, according to a study by Dr. Deanna Kuhn, Michael Weinstock and Robin Flaton, developmental psychologists at Columbia University.
A significant portion of the jury pool latches onto a theory about a case, and holds on for dear life, the study found. Once they have adopted a "story" that explains the case, people in this group are unwilling to consider alternative stories, or weigh evidence that conflicts with their notion of the way things really happened.
This kind of juror also tends to choose more extreme verdicts, and to be more certain of the choice.
They see their jobs as jurors as "identifying a single, certain truth, rather than weighing alternatives whose truth can never be known with certainty," the study concluded.
That kind of reasoning undermines the jury process, the researchers say, for "it is faith in the power and ultimate triumph of reason that makes societies willing to entrust an individual's fate to the collective reasoning of peers."
Ms. Flaton, a New York City lawyer and doctoral candidate who co-authored the study, said the results also underscore the need for schools to do a much better job of teaching "critical thinking."
It may also suggest a need for better "juror education" -- a quick course in reasoning before jurors hear a case. "It's something to think about," she said.
The Columbia study was published last September in Psychological Science, the journal of the American Psychological Society, and it has drawn considerable attention, including some from news organizations covering the O. J. Simpson trial.
Most often the study was cited by the media -- mistakenly -- to support the idea that the opening statements were crucial to the case because that's when many jurors make up their minds about a defendant. "Our study said nothing about that," Ms. Flaton said.
Nevertheless, she said, the authors got calls from defense attorneys in a panic because they often make no opening statements. They wait instead to see whether the prosecutors ++ can make an adequate case against their client.
"We did not look at when people make up their minds," she said. Here's what they did:
Dr. Kuhn, Mr. Weinstock and Ms. Flaton took a group of 154 racially, educationally and economically diverse subjects ranging from ninth-graders to adults in their 60s. All listened to a 25-minute taped re-enactment of an actual murder trial.
Evidence in the case said that the defendant, Frank Johnson, was quarreling in a bar with a man named Alan Caldwell. Mr. Caldwell threatened Mr. Johnson with a razor, and Mr. Johnson left the bar.
Later that night Mr. Johnson returned, and the two men argued again. They took the dispute outside. The next thing anybody knew, Mr. Caldwell was dying of knife wounds and Mr. Johnson was holding the knife.
The prosecution said Mr. Johnson came back to the bar intending to kill Mr. Caldwell, and then did so. That's first-degree murder. The defense insisted that Mr. Caldwell threatened Mr. Johnson again with the razor, and that Mr. Johnson protected himself with his knife. Self-defense.
If you're a juror, whose story do you believe? How do you rule out the other side's version of events, and how do you deal with evidence that doesn't fit the story you favor?
Earlier studies have revealed that jurors use evidence to construct in their mind a plausible narrative "story" of what happened. They compare the "story" with the verdict alternatives they've been asked to consider, and then select the best match.
The Columbia study, however, found after careful questioning that the "jurors" didn't all reason in the same way.
At one end of the spectrum, jurors listen to the often-conflicting evidence and construct several different stories of what happened, each aligned with a different possible verdict. After weighing each story against the others, and against the evidence, they select the one with the strongest match, and least disagreement, with the evidence.
A significant portion of the jury pool, however, constructs a single plausible story with little or no consideration of the alternatives, dismissing conflicting evidence. For example, one group of "jurors" concluded that Mr. Johnson killed Mr. Caldwell in self-defense. They held to that theory even when confronted with evidence that Mr. Caldwell was found dead with his razor in his back pocket. These jurors, the researchers assert, are less skilled thinkers, and use less "competent" reasoning that damages the trial process.
"Competent" reasoning for a juror, Ms. Flaton said, means a willingness to weigh alternative stories and conflicting evidence, and to abandon a theory when it is eroded by the evidence. That's not easy. "It takes work, a lot of energy to think."
People who tended to adopt and stick by a single theory in the murder case also tended to be more highly certain of their decision than those who weighed the various alternative scenarios.
And while dead-certainty might seem to be desirable for a juror, Ms. Flaton argues that it is not.
"That's a lay idea," she said. "Those people aren't allowing themselves the leeway to look at evidence of things they didn't consider. It's through arguing and listening to things you might not have considered that you're really able to come to the best sort of answer.
"There's value in having high certainty, but not absolute certainty, because it closes the door to further thinking," she said.
The good news, the study suggests, is that the design of the jury system may counterbalance such reasoning by exposing jurors to each other's thinking.
"Other jurors will have made initial choices of different verdicts and will interpret the evidence in different ways. Social exchange with these other minds may thus go a long way in providing the corrective," the study said. The Columbia researchers have not tried to fashion demographic profiles of skilled reasoners, or jurors more likely to choose extreme verdicts. "As scientists, we are reticent to use the knowledge to help somebody in [that] way," Ms. Flaton said. "That's not what the justice system is about."
The only demographic factor that seemed to correlate with more-skilled reasoning was the individual's level of education. The more education acquired or aspired to, the better the reasoning.
Is this a reflection of I.Q. or experience? "We have no idea," she said. "Education is going to assist you somehow, but we don't know exactly what it is."
Dr. Kuhn's work suggests that reasoning skill may well play a similar role in the way individuals perceive the world and respond to ideas about their social environment.
In earlier studies of argumentive reasoning, Dr. Kuhn asked people to describe and justify their ideas about the causes of social problems, such as school failure and criminal recidivism. Some could see their view as one of several alternative theories one could draw from the evidence. Others were more absolutist, with firm ideas about why things happen and little willingness to consider other possibilities.
"We all have an investment in the positions we hold, so being open minded, or considering pieces of evidence that don't match, is hard," Ms. Flaton said.
"People think that if you come out strong and say 'This is true,' that somehow your own positioning makes you stronger," she said. "But in reality, it's not the best way to make decisions about issues, or to think about things. You always want that door open for the next piece of evidence. Then you might have to revise or discount your theory."
"It's not about right or wrong," she said, "but about thinking well."
Frank D. Roylance is a reporter for The Baltimore Sun.