COLUMN ONE : Why Jurors Err: They’re Just Human : As the Simpson trial opens, juries’ credibility is under scrutiny. Experts say any panel is vulnerable to biases and missteps. But the system still manages to produce sound verdicts.

Listening to the car radio one morning last fall, Hazel Thornton heard callers to a talk show belittle the jurors in the Reginald O. Denny beating trial, which had just ended. The “stupid idiots,” she heard them say.

Thornton shuddered. She was a juror in the trial of Erik Menendez, who was accused with his brother of murdering their wealthy parents. As she drove to the courthouse, she worried that “people might say the same thing against us.”

When she met her fellow jurors that day, she made a point of polling them to find out how many had college degrees. It was a defensive gesture--to prove they were smart.

Nonetheless, when her jury deadlocked many weeks later, Thornton and fellow jurors became the butt of jokes across the country. Their failure to convict prompted people to ask: Is there something wrong with the jury system?

Now O.J. Simpson will be tried in the murders of his former wife and her friend, providing the world with a forum for examining the flaws of juries in yet another Los Angeles case.

Jurors do make lots of mistakes. They err most often in understanding and applying the letter of the law and may bend it when their sympathies or biases favor a particular outcome. In criminal cases, for instance, one survey showed they are more likely to acquit a guilty person than to convict someone who is innocent.

But for all their faults, juries usually manage to produce verdicts that are defensible, if not perfect, according to social scientists.

“It depends on what your tolerance for error is,” said forensic psychologist Elizabeth Loftus. “We have a system that works well a lot of the time, but it also makes mistakes.”

The imperfections of jurors reflect the frailties of human nature:

* They can be capricious, swayed by emotional appeals or prejudice, and will ignore the law if they believe its result would be unjust.

* Juries sometimes just cannot agree and deadlock, a problem that appears to be more acute in parts of California than elsewhere.

* Jurors have trouble understanding judges who give convoluted instructions and become overwhelmed by complex evidence.

* In long trials, which often are the most highly publicized, jurors can be influenced by the unusual pressures, and the composition of the panels tends to be different.

Even their most ardent defenders believe jurors should be given a more active role during trials to improve their comprehension. In the tradition-bound judicial system, jurors usually are not allowed to ask questions or even take notes. They are only instructed about the law at the end of a trial, after they may already have formed strong impressions.

Some jurors complain that they had questions about key elements of the case and resent being forced to reach a verdict without obtaining the answers.

“There isn’t anything fundamentally wrong with having ordinary people make important decisions,” said Saul Kassin, a forensic psychologist at Williams College in Massachusetts. “But there is a lot wrong with the way jury trials are managed.”

Sometimes the public unfairly blames jurors for unpopular verdicts that can be traced instead to key mistakes in rulings by judges or poor performances by the lawyers. The evidence jurors are allowed to consider also may be substantially different from what the public may know about a case.

Many believe the prosecution was weak in the state trial in which the jury failed to convict four Los Angeles police officers accused of beating motorist Rodney G. King in 1991. The later federal trial, which produced convictions of two officers on civil rights charges, was starkly different from the first, from the evidence presented by the prosecution to the judge’s instructions to the jury.

Jurors may have feared the possibility of unrest when they produced only one felony conviction against two men accused of beating truck driver Denny at one of the flash points of the riots that followed the initial King verdict.

But most legal experts believe the prosecution erred in bringing excessive charges against the defendants.

Judges are more apt to convict than juries, surveys indicate, but nevertheless agree with most jury verdicts in their courtrooms. Even when jurors become muddled by complicated evidence, their verdicts are usually sound, research shows, because the most capable member of the panel guides the deliberations.

“The weakness is that there is always one bleeding heart in there who has to be convinced,” said Long Beach resident Edith Downey, 56, who has sat on four Los Angeles County criminal juries. “But generally they come around because of logic.”

Blaming the jury for unpopular verdicts is nothing new: Until the late 17th Century, jurors in England could be fined or imprisoned for returning a verdict opposed by the court.

And just a decade ago such prominent Americans as then-U.S. Supreme Court Chief Justice Warren Burger were deriding the ability of juries to decide complicated civil cases.

* When Jurors’ Emotions Rule

Borrowed from the British, the early American jury system reflected the public distrust of judges from colonial times. When memories of the Revolution dimmed and competent judges became more plentiful, American courts began reining in juries, allowing judges to reverse decisions and instruct jurors.

What concerns many critics today is that jurors have not been reined in enough. They can allow their emotions and personal experiences to color their perceptions of the evidence, a fault acknowledged even by the system’s strongest defenders.

“Jurors will hang their hats on the most insane things,” said John Tyre, a Los Angeles County criminal defense attorney for 13 years. Even though verdicts are by and large correct, he said, “they will look up at the defendant and say, ‘He has a tattoo. He must be a bad guy.’ It scares me sometimes to think about the stuff that goes on.”

In a personal injury civil trial, Loftus said, a jury awarded little money to a woman who suffered horrible back pain because they noticed she had changed her toenail polish three times during the trial. The weather was hot, and the woman wore sandals to court.

“They figured her back couldn’t have hurt that much if she could bend down to paint her toenails,” said Loftus, a professor of psychology at the University of Washington. “So it is those kinds of things you do have to worry about. . . . Jurors bring in their personal stories and personal experiences all the time.”

During Menendez trial deliberations, a man on Erik Menendez’s panel told fellow jurors of wishing his parents had attended his football games when he was young. He argued that Jose Menendez could not have been as bad as his sons portrayed him because he had attended his sons’ tennis games. The juror was one of five who voted for first-degree murder.

Some researchers believe caprice may be to blame for an Aug. 19 jury award of $2.9 million to a New Mexico woman who was scalded by coffee at a McDonald’s restaurant. (A state judge recently reduced the award by more than 75%.)

McDonald’s serves unusually hot coffee, and the elderly woman who spilled it suffered third-degree burns. The jury learned that other customers had also been burned, but the corporation had failed to post warnings.

“Usually the jury gets mad,” said jury consultant Thomas Beisecker, who teaches about juries at the University of Kansas in Lawrence. “Usually there is someone in the courtroom they don’t like. It could be the behavior of . . . the corporate representatives.”

Sympathy, like anger, also may color a verdict.

Skillful defense lawyers often try to put someone other than the defendant on trial. Many years ago Texas defense lawyer Percy Foreman did this when he defended a woman who confessed to shooting her husband to death.

During the trial, described by jury experts Valerie Hans and Neil Vidmar in their book “Judging the Jury,” the flamboyant defense lawyer presented evidence that the husband had poisoned dogs, stomped a puppy to death and wrung the neck of a parakeet. The jury acquitted the wife.

“The jury was ready to dig up the deceased and shoot him all over again,” said Foreman, who also represented the convicted assassin of Martin Luther King Jr. Foreman died in 1988.

This tendency to blame victims is part of the American psyche, according to Hans. She said it is reflected in some tabloid reports that suggest Nicole Brown Simpson may have been promiscuous. Another consultant said such coverage may be sparking sympathy for the ex-athlete.

“If you have a defendant who is attractive in some form to the jurors, there will be some degree of sympathy and it will tend to overcome the evidence,” Beisecker said. “But if the evidence is clear, it probably will not.”

Prejudice also can creep into deliberations. Sharon Danley, a 45-year-old medical transcriber, was called to serve on a jury in Santa Monica several years ago and anticipated a quick verdict. Two men had been accused of committing a sex act in a restroom. They denied the charge, and the defense challenged the integrity of a security guard who claimed to have seen them.

Most jurors wanted to acquit, but one woman refused to budge, making derogatory comments about gays.

“I have been in the theater,” Danley quoted her as saying. “I know what these people are like.” The jury hung.

* When Juries Get Stuck

The deadlock, after a week of deliberations, was frustrating for Danley, but no match for what Jude Nelson went through.

Nelson was a juror in the Lyle Menendez trial. He reported for duty June 12, 1993, and was not released until Jan. 29, 1994, when his panel deadlocked after five weeks of deliberations. Half the jurors favored convicting Menendez of murder, the other half of voluntary manslaughter.

“I spent 25 days there just hollering and screaming and yelling to no avail,” said Nelson, who voted for first-degree murder.

Los Angeles County Dist. Atty. Gil Garcetti was so frustrated that he called on Californians to consider dropping the unanimous verdict requirement for some kinds of criminal cases. Statistics on deadlocked juries compiled by The Times suggest the prosecutor may indeed have cause for concern.

Many experts believe about 5% of juries nationally deadlock, forcing retrials at considerable expense, compromises, or, in criminal cases, dismissal of charges.

But deadlock rates reported by prosecutors in five large California counties range from 13% in Los Angeles in 1993 for felony trials to 6% in Alameda County, which includes Oakland and Berkeley.

By comparison, 2.3% of felony trials in New York’s Manhattan borough deadlocked in 1993, and 1.88% in Florida’s Dade County, which includes Miami.

The national rate for criminal trials in federal court was 2.65%. Federal juries in California deadlocked at about twice that rate--4.59% of the time.

Some critics suspect juries in California may be more erratic because of the state’s cultural climate. Harvard law school professor Alan Dershowitz--months before he joined Simpson’s defense team--condemned California as “the laughingstock” of the nation because its juries fail to convict “obviously guilty” people.

“I don’t think I want to be quoted on this,” said one prominent jury researcher, “but maybe you have more crazy people out there in California. One of the ways juries get hung--it is not frequent, but it happens--is that people think God tells them this is a guilty or innocent person, and they refuse to deliberate.”

Garcetti said the higher rates in California might be explained by Proposition 115, the 1990 ballot measure that limited the ability of attorneys to screen prospective jurors. Many attorneys contend that judges, who can now do all the questioning, fail to probe deeply enough for biases that could deadlock a jury.

Researchers also cite a variety of other possible explanations for the disparity: different charging practices among counties, more diverse jury pools for some courts and differences in jury instructions.

Juries usually deadlock when the evidence is evenly balanced. Those that vote before deliberating or by secret ballot tend to deadlock more often than juries that vote openly after discussion.

Nevertheless, most juries reach consensus because the pressure of the group is usually too strong. Unlike Henry Fonda in “Twelve Angry Men,” jurors whose views are in the minority usually cave in. The smaller the jury, researchers believe, the less likely it will deadlock because there will be fewer minority jurors to support each other.

Sometimes dissenting jurors give up just so they can go home. Jurors have even been known to toss a coin, according to Cal State Dominguez Hills law professor Franklin Strier, author of a new book on juries.

San Francisco U.S. Atty. Michael Yamaguchi, explaining the fewer hung juries in federal court, noted that California law requires jurors in state trials to find guilt “beyond a moral certainty,” whereas federal jurors are given a less precise--and easier-to-meet--definition of “reasonable doubt.”

Federal judges are also allowed to exert more pressure than California judges to break deadlocks. By giving what is known as the “dynamite” instruction, federal judges urge the minority on the juries to re-examine the case and try to reach agreement.

The strains of serving on notorious cases also may exacerbate divisions on the panel, although jurors usually feel even greater pressure to reach a verdict.

For Nelson, the Menendez case meant sitting around day after day, confined in close quarters, always at the beck and call of the court. “It was stressful in that we had these responsibilities put upon us,” said Nelson, who said he lost his job as a rock band manager because of the trial’s length.

“I felt a lot of pressure to reach a verdict. I was incredibly frustrated and angry.”

* Who Serves on Long Trials

It is not known whether juries in notorious cases like the Menendez killings actually deadlock more than others. What is known is that their makeup is probably different because few people can afford to serve on long trials.

Although spot surveys indicate that people who show up for jury duty are more educated than the general population, jurors who serve in cases longer than 20 days may be an exception. Those panels tend to have fewer college graduates and more unemployed, retired, female and unmarried members, according to a 1987 study of federal civil trials by the Washington-based Federal Judicial Center.

In jury questionnaires obtained by The Times, jurors in recent Los Angeles death penalty trials lasting one to two months were overwhelmingly retirees or employees of the Post Office or other government agencies or aerospace firms that pay for extended service. Attorneys complain that both lower-income and upper-income residents rarely serve in protracted cases.

Certain occupations may be overrepresented on such juries. This may happen when a major employer in town has generous jury benefits. Engineers--”people who want to make the pieces fit”--sit frequently on juries in Seattle because Boeing pays well for jury duty, Loftus said.

Such imbalances can be a factor in the outcome of some cases. An engineer may be more likely to evaluate scientific evidence properly--or to balk at a conviction if the evidence does not neatly fit together, consultants say.

Jurors’ age can also play a role. For example, a majority of the King jurors in the state trial were 50 or older--the kind more likely to be sympathetic to the police, experts said. The jury in the second trial had only three jurors over 50, according to a jury consultant for the defense.

* Trouble With the Law

When jurors err, it is often because they do not follow directions. They have enormous trouble understanding the judges’ instructions, a problem social scientists blame on legal mumbo jumbo, not on jurors’ intelligence.

“The most serious problem that jurors encounter in their efforts to get things right appears to be an inability to apply instructions correctly,” said Richard Lempert, a professor of law and sociology at the University of Michigan.

Sometimes jurors are given too little direction. In one major civil trial, jurors unknowingly denied the plaintiff money because they could not understand the verdict form. The judge had never bothered to explain it.

The law also asks jurors to do what experts contend is nearly impossible--to wipe from their minds facts they are not legally supposed to consider.

When the men accused of beating truck driver Denny went on trial, the news media and community leaders expressed fears that harsh verdicts might spark renewed unrest. The judge told the jurors not to consider the ramifications of their verdicts, but some did.

Jo-Ellan Dimitrius, the Pasadena trial consultant who was hired by the Denny defendants and now works for Simpson, said one juror went to the blackboard during the last day of deliberations and wrote the words “Compassion,” “Unity” and “Future.”

The juror later explained that he wanted panelists to have compassion for each other and hoped the verdict would bring unity to Los Angeles’ future. The Denny jurors “hated one another,” Dimitrius said, threatening and swearing at one another during deliberations.

Although the juror insisted he had not considered the verdict’s ramifications, the possibility of unrest “subconsciously” affected him, said Dimitrius, who interviewed the jurors after the trial.

The Denny jurors returned one felony conviction out of 15 counts filed. The felony, a mayhem conviction against 20-year-old Damian Monroe Williams, was the lesser of two options and carried a maximum prison term of eight years instead of life.

(Even judges can’t help but consider facts they should ignore. In one experiment, judges awarded a person injured in a burning accident more money when they knew that the corporation had tried to recall the responsible device--despite being told to ignore that evidence.)

Sometimes the evidence is too complex for most jurors, or so dry and technical that they tune out, counting the light fixtures overhead to relieve their boredom.

The kind of evidence that will be critical in the Simpson trial particularly stumps jurors, according to jury experts. Jurors tend either to overestimate or undervalue the importance of such scientific evidence as DNA because the error rates and statistical probabilities are confusing.

Not surprisingly, research suggests that the more educated the jury, the more likely it is to interpret the evidence correctly and produce a sound verdict. But requiring a minimum level of education could deprive panels of people with an understanding of issues gained outside the classroom, some experts argue.

“The jury benefits from diverse perspectives,” Lempert said. “So you don’t want all jurors to reach a certain magic standard because the janitor may know some things about how pipes work, or somebody else might know something about how the police work.”

Hazel Thornton’s fellow jurors in Erik Menendez’s trial included blue-collar workers and a Ph.D. Several had college degrees. After her panel deadlocked, she said she heard someone on talk radio declare that it looked as though “they had just moved the stupid Denny jury over to the Menendez case.”

Despite her early angst, Thornton, who voted for manslaughter instead of murder, is bearing the ridicule well.

“They don’t know what they are talking about,” said the 37-year-old telephone company engineer. “They weren’t there.”

Next: Manipulating the jury.

About This Series

In this four-part series, The Times examines the strengths and flaws of the American jury system and the need for reform.

* Today: Deadlocks in recent high-profile cases have thrown the spotlight on the U.S. jury system, raising questions about whether it deserves to survive.

* Monday: High-priced consultants are helping defendants pick favorable juries, but how much of a difference can they really make?

* Tuesday: The Times Poll examines attitudes toward jury service and the jury system in Los Angeles County.

* Wednesday: Warning that the jury trial system could self-destruct without change, a small but growing number of legal experts are calling for sweeping reforms.

Unable to Decide

Hung juries have long infuriated the public because of the expense required to stage a new trial. Experts estimate that about 5% of all trials end in a deadlock. Los Angeles is among several California counties that have high rates of hung juries in felony trials at the state court level.

Riveting Juries

America is fascinated by a good jury trial. Here are five that riveted the public and reverberated long after they ended. One case brought about a change in the law. Two set off riots. Some were characterized by bitter arguments among jurors that continued, in one instance, for months after the trial had concluded. Most raised questions about the impact of massive pretrial publicity on jurors’ attitudes towards the defendant.

Rodney G. King

* BACKGROUND: On March 3, 1991, motorist Rodney G. King was stopped by law enforcement officers after a chase. Several officers were captured on videotape kicking King, an African American, and beating him with batons. Sgt. Stacey C. Koon and Officers Laurence M. Powell, Theodore J. Briseno and Timothy E. Wind, all of the LAPD, were charged with 11 criminal counts including assault with a deadly weapon and assault under color of authority.

* JURY SELECTION AND COMPOSITION: The trial was moved to Ventura County. The jury of six men and six women was seated after one month of questioning. There were 10 whites, one Latina and one Asian American but, notably, no African Americans. Jurors’ identities were kept confidential. They were evenly divided between Democrats and Republicans, ranged in age from 38 to 65 and included retirees, professionals and blue-collar workers.

* DELIBERATION TIME: The sequestered jurors deliberated for seven days.

* JURY CONDUCT: The jury was bitterly divided over many of the charges. Some jurors who spoke to reporters demanded anonymity. Some feared retaliation; some reeived death threats.

* RESULT: The jury found the officers not guilty on 10 counts and was deadlocked 8 to 4 in favor of acquittal on one count against Powell. Reaction was swift, with many calling the verdicts racist. Hours after the verdicts, angry citizens torched buildings and looted stores in became three days of the worst urban rioting in U.S. history. Powell and Koon were convicted in a federal civil rights trial and are now serving prison sentences.

Erik & Lyle Menendez

* BACKGROUND: The brothers were charged with first-degree murder in the 1989 shotgun slayings of their parents in their Beverly Hills mansion. The prosecution portrayed them as coldblooded killers motivated by greed. The defense claimed they killed in self-defense after years of emotional, physical and sexual abuse. The charges carried the death penalty. They were tried together, before separate juries.

* JURY SELECTION AND COMPOSITION: Selection was complicated by intense pretrial publicity, which the defense contended jeopardized the brothers’ right to a fair trial. Jury selection took approximately three weeks for Lyle Menendez’s jury and a week longer for his brother’s. Prospective jurors filled out a 34-page questionnaire which probed issues of sexual abuse, family violence and self-defense. Lyle’s jury had five men and and seven women; seven of the jurors were parents. Erik’s jury had six men and six women; nine were parents, seven were over 50.

* DELIBERATION TIME: The jury for Lyle Menendez deliberated 25 days before announcing that it was hopelessly deadlocked. The Erik Menendez jury deliberated for 19 days before deadlocking.

* JURY CONDUCT: Jurors were not sequestered. In the Erik Menendez jury, votes were split largely along gender lines, with the votes for first-degree murder verdict in the killing of Jose Menendez all cast by men. One juror recently accused another in a lawsuit of slandering her on a TV talk show.

* RESULT: Both trials ended in hung juries. The case spawned book and movie deals. The brothers remain in custody without bail awaiting retrial.

Bernhard Goetz

* BACKGROUND: Goetz, who is white, shot four black teen-agers on a New York subway in 1984. He claimed they were about to rob and beat him; the young men said they were only panhandling. Goetz was seen by some as a hero acting in self-defense and by others as a trigger-happy vigilante and racist. He was charged with 13 criminal counts, including four counts of attempted murder, and faced up to 30 years.

* JURY SELECTION AND COMPOSTION: After 10 days of jury selection, 12 jurors and four alternates were seated. Six of the 12 had been victims of crimes, three in the subway. There were eight men and four women, two blacks, nine whites and one Latino.

* DELIBERATION TIME: The sequestered jurors deliberated 30 hours over four days. They voted 35 times before reaching a verdict.

* JURY CONDUCT: At least one juror appeared on “Larry King Live” after the trial. None voted to convict Goetz of the more serious crimes, according to several jurors’ reports. Two jurors sold their stories to newspapers in New York and one wrote a book.

* RESULT: After a seven-week trial, Goetz was found guilty only of illegal gun possession. He was sentenced to one year in jail and a $5,000 fine. He served 250 days. One shooting victim who was paralyzed from the waist down filed a $50-million lawsuit against Goetz, which is still pending.

William Kennedy Smith

* BACKGROUND: The nephew of Sen. Edward M. Kennedy was charged with raping a woman at his family’s estate in Palm Beach, Fla. in 1991. The Kennedy name, as well as the senator’s testimony, drew hundreds of journalists. The extensive coverage ignited debates about pretrial publicity and the right to a fair trial.

* JURY SELECTION AND COMPOSITION: Both sides attempted to use massive pretrial publicity to influence potential jurors. Jurors were questioned about their attitudes toward the Kennedy family and about pretrial coverage. One prospective juror, called a “walking mistrial” by the judge, was dismissed after she revealed that members of the media had contacted her. It took three weeks to seat the six-person jury of four women and two men. The jurors were sequestered; their average age was 52 and none were college graduates.

* DELIBERATION TIME: After 10 days of trial, jury deliberation took only 77 minutes.

* JURY CONDUCT: Two female jurors wiped away tears as the verdict was read. One appeared on the Phil Donahue TV show with Smith’s attorney after the trial. The attorney, Roy Black, and the juror began dating a year after the trial.

* RESULT: Smith was found innocent on the rape charge and a misdemeanor count of simple battery. His accuser shed her anonymity and agreed to be interviewed. Most, but not all, news organizations had withheld her identity when she testified because of policies against publishing the identity of accusers in rape cases.

Dan White

* BACKGROUND: In November, 1978, White, a former police officer and a conservative law-and-order San Francisco supervisor, shot and killed liberal Mayor George Moscone and Supervisor Harvey Milk, San Francisco’s first openly gay public official. White, who had resigned his seat 17 days earlier, shot Moscone after the mayor refused to reappoint him. Milk had reportedly argued against his reinstatement. The murders changed the political landscape of the city.

* JURY SELECTION AND COMPOSITION: The jury of seven women and five men, mainly white, middle-class and Catholic, like White, was selected from a panel of 250 people. Six of the 12 jurors wept openly when a tape of White’s sobbing confession.

* DELIBERATION TIME: The panel deliberated 36 hours over six days, reaching unanimous guilty verdicts, first on the Moscone slaying and three days later on Milk’s slaying.

* JURY CONDUCT: Jurors, who were sequestered, received death threats. Some changed jobs and some moved out of the Bay Area. One said it was “the worst thing that ever happened to me.”

* RESULT: White, who was facing the death penalty, was found guilty of the lesser charge of voluntary manslaughter. The defense had argued that White was suffering from a deep depression aggravated by eating sugary junk food and was acting with diminished capacity. This became known as the “Twinkie defense.” The verdict touched off a night of rioting in San Francisco. In 1981, the diminished-capacity defense was abolished. White served a little more than five years in prison, was paroled in 1984 and committed suicide in 1985.

Researched by NONA YATES / Los Angeles Times

COUNTY* HUNG JURY RATE 1991 1992 1993 * Los Angeles 13% 14% 13.4% * Riverside 5% 9% 10% * Santa Clara 11% 8% 8% * Orange 7% 8% 8% * Alameda 3% 5% 6%

* No figures available for San Diego, San Bernardino or Ventura counties

Compiled by researchers Norma Kaufman and Nona Yates