I was a jury consultant for 30 years. My primary job was to help trial attorneys determine if prospective jurors had innate predispositions that would bias them against our case.

I’ve worked on many high-profile trials over the years, including that of Dr. Jack Kevorkian’s first physician-assisted suicide trial. I’d like to share with you what I’ve seen and learned.

First up, some legal “lingo”. You probably know from watching Law and Order all about prosecutors and defendants. But in civil cases, the person suing is called the plaintiff, and the party being sued is the defendant.

A jury of one’s peers? Uh, not so fast.

The sixth amendment to the U.S. Constitution guarantees criminal defendants the right to an impartial jury of one’s peers, which is supposed to prevent jurors from being biased. For reasons I’ll explain shortly, this seldom occurs. Sadly, it is well documented that juries of defendants of color seldom reflect their background and experiences – in other words, are their peers. As outrageous and unfair as this is, personality type has an even greater impact on our judicial system, because it affects practically every trial – whether the parties are people of color or not. 

My biggest take-away from interviewing thousands of prospective jurors in hundreds of cases and having conducted dozens of mock trials is this: People see what they want to see, and their personality type predisposes them to see things in quite predictable ways.

Temperament predisposes jurors to decide for one side or the other – before hearing any of the evidence.

“Temperament,” a grouping of personality types popularized by the late psychologist David Keirsey, is at the core of each of the 16 personality types. In my work, I call these four groups Traditionalists, Experiencers, Conceptualizers and Idealists. Why my emphasis on temperament? By identifying a juror’s temperament during Voir Dire (the jury selection process), I was almost always able to predict who the foreperson would be, which party jurors would side with, and how generous or frugal they would be in awarding money damages.

There are significant differences between criminal and civil cases. For obvious reasons, the stakes are much higher in criminal trials. The bedrock principle of our criminal justice system is that a defendant is presumed innocent until proven guilty. The burden of proof is higher and requires prosecutors to prove their case “beyond a reasonable doubt.” 

In civil cases, plaintiffs must prove their case only by “a fair preponderance of the evidence,” a chance greater than 50% that their claim is true. Civil cases can range from small fender-benders to multi-million-dollar medical malpractice claims to multi-billion-dollar commercial disputes. Where criminal cases are about justice (and often punishment), civil cases are mostly about money, called “damages.” 

There are two types of damages a plaintiff can be awarded: “economic,” which are tangible and quantifiable: medical costs, lost wages, repairing or replacing damaged items.  And “non-economic” damages, which are far trickier since they involve intangibles like “pain and suffering,” “loss of companionship,” and “loss of enjoyment of life.” The personality types of jurors can have an enormous impact on the amount of money awarded, especially with regards to non-economic damages.

How type and temperament influence jurors’ behavior.


Traditionalists comprise all four Sensing Judging types: ESTJ, ISTJ, ESFJ and ISFJ. They tend to be responsible, dependable, organized, hard-working, productive and detail-oriented people. While they make up about 46% of the US population, they generally comprise about 75% of juries.  Why? Because of their enormous sense of duty, they don’t try to get excused from jury service.

This has huge implications. For example, in criminal cases, Traditionalists often favor the prosecution strongly. They think, “If the cops arrested this guy, the state’s taken the time to try him, and the case is being heard by a judge, he’s probably guilty – if not of this crime then surely of something else.” 

And what about the presumption of innocence? Tragically, and in direct contradiction to the Constitution, there is more often the presumption of guilt.

In civil cases, being the practical, concrete, fiscally conservative folks they are, their hard wiring prevents the Traditionalist from buying into “squishy” constructs that can’t be measured such as pain and suffering and loss of life’s enjoyment. And remember, they often make up 75% of juries.

One of the trials I worked on was Connecticut’s “Woodchipper Murder,” a gruesome case involving a husband accused of killing his wife and putting her body through a woodchipper to destroy evidence. The case garnered much national attention and became the inspiration for the movie Fargo. The first trial ended in a mistrial due to one “hold-out juror.” At the retrial, prospective jurors were interviewed to determine if they could be impartial. Upon questioning, the first prospective juror admitted that she had read one or two articles a day about the first trial, believed the defendant’s wife was dead (an element the state was obligated to prove), and the defendant was “probably guilty.” Rather than excuse her, the judge said “Madam, you look like a very intelligent woman. If I instructed you that you had to put everything you’ve heard or read about this case aside…just wipe the slate clean, and give the defendant a fair trial, you could do that, couldn’t you?” The woman said “yes, she could.”  

From her responses to this, and previous questions, I was quite sure she was an ISTJ (a Traditionalist), and not at all surprised to hear her say she’d obey the judge’s instructions and follow the law. She, and the judge probably, even believed it.


Experiencers comprise all four Sensing Perceiving types: ESTP, ISTP, ESFP and ISFP. They tend to be fun-loving, playful, casual, adaptable, realistic people who like to live in the moment. Not usually enamored of authority, they cherish freedom and chafe at rules that constrain their actions.

They make up about 27% of the US population and represent about that same percentage of jurors, but only if they think the experience will be more pleasurable and engaging than their work. If not, they are likely to try and get excused.

Although they can be quite rebellious – and may get in trouble for breaking the rules in their youth – they tend to be quite conservative and inclined to side with the prosecution. This is especially true of Thinking Experiencers (STPs). And they can pose a real challenge for plaintiffs when it comes to awarding money damages, as the following case illustrates:

On her way to work one day, a plaintiff client stopped at a Dunkin Donuts to pick up her morning coffee. It had snowed the night before and while the parking lot had been plowed, the woman slipped on a patch of ice the plow hadn’t cleared and suffered serious, permanent injuries to her back which left her in continuous pain. Multiple therapies failed and she had to have a pump implanted into her side which continually delivered powerful pain medication. I conducted a mock trial focus group where pretend jurors heard both sides of the case. Credible evidence was presented from medical experts attesting to the acuteness of her pain and the necessity for the pump to help her tolerate it. Viewing the deliberations from behind a one-way mirror, the attorneys who hired me were incredulous at one ESTP (Experiencer) male's comments. He had discounted the expert’s testimony and showed little empathy for the plaintiff’s plight: “That’s what you get for wearing heels in the winter. She should have known better. And besides, maybe she likes the high she gets from the drugs.” In my experience with many other cases, his comments were not atypical or unexpected from jurors who are (more often male) Thinking Experiencers.


Conceptualizers comprise all four Intuitive Thinking types: ENTJ, INTJ, ENTP and INTP. They tend to be logical, confident, competent, assertive, intellectual, strategic, and competitive. While only about 10% of the US population, Conceptualizers dominate leadership positions in every field, and may represent as many as 80% of all executives. If they are not the foreperson on a jury, they are certainly always influential.

Because they tend to be very career-focused, often have important jobs, are strategic, and can be quite persuasive, Conceptualizers can usually figure out how to get out of jury duty if they want to.

Being Thinkers who are not naturally empathetic, they tend to lean towards the prosecution in criminal cases, and towards the defense in civil cases. They don’t tend to identify with the underdog or look for mitigating circumstances that might excuse their behavior.

Conceptualizers can be especially influenced by the performance of competent attorneys or expert witnesses.

Even a juror’s reaction to a particular witness can impact a trial’s outcome. A 45-year-old construction worker filed a medical malpractice claim against a surgeon he alleged had botched an operation to correct a medical condition. As a result, the plaintiff could no longer work or engage in much physical activity. The defendant argued the outcome resulted from a pre-existing condition he and the plaintiff discussed in depth before the operation, and that he told his patient he could not guarantee a positive outcome. One juror was a sixtyish ESFJ (Traditionalist) woman. The problem arose almost as soon as the plaintiff’s medical expert sat in the witness box to testify. While this INTJ (a Conceptualizer) expert had impressive credentials, his communication skills were abysmal. Typical of many competence-driven Conceptualizers, humility was not his strong suit. He ended up using a lot of medical jargon which made him appear smart but made jurors – including the ESFJ woman – feel stupid. But in addition to being a Traditionalist, the juror was also a dominant Feeling type. What really turned her off and cost the plaintiff her vote, was the expert’s condescending attitude and combativeness when cross examined by the defendant’s attorney.


Idealists comprise all four Intuitive Feeling types: ENFJ, INFJ, ENFP and INFP. Typically, they are empathetic, perceptive, sensitive, idealistic, compassionate and communicative people. Comprising about 17% of the US population, they are the most sympathetic towards criminal defendants – especially if the offense is relatively minor, and the defendant is a minority. They seek to understand the underlying causes of human behavior, see people’s potential, believe in second chances, and have an idealistic view of how society can be improved. With rich imaginations, Idealists can easily put themselves in others’ shoes and are most likely to award generous non-economic damages. 

While waiting in line at a fast food restaurant, a metal menu sign fell on the fifty-year-old plaintiff’s head. A neurologist testified that she suffered considerable brain damage, and the plaintiff and her husband credibly testified how the accident had significantly reduced her cognitive abilities and left her chronically depressed, appreciably diminishing her quality of life. The jury quickly agreed the restaurant was “liable” (responsible) and awarded all the economic damages her attorney asked for, which the practical, realistic, concrete Sensors on the jury found easy to calculate. 

However, then the discussion turned to non-economic damages - “pain and suffering,” “loss of companionship,” and “loss of enjoyment of life.” The plaintiff was also entitled to all of that. The three Idealist (NF) jurors expressed their outrage at the defendant’s negligence. And being Intuitive Feeling types, they could easily imagine the horrendous impact this incident had on all aspects of the plaintiff’s life; how it affected her most important relationships and left her with little to look forward to in the future. They made a strong and passionate case for awarding reasonable non-economic damages but couldn’t convince the Sensing types who made up the jury’s majority. Although upset, they ultimately backed down for fear of creating disharmony among the jury – a dynamic I have seen played out many times before.

My closing argument (even if it doesn’t please the Court)

I have only scratched the surface and didn’t have the opportunity to discuss other integral issues such as how the Courts and the legal system don’t believe in psychology, which comes with huge consequences. What I do hope to have conveyed is that personality type can have a significant impact on the outcome of practically every criminal and civil trial. Something to consider if you or a loved one is ever involved in litigation.

Paul Tieger
Paul D. Tieger is the Founder and CEO of SpeedReading People, LLC. He is an internationally recognized expert on – and author of five breakthrough books about – personality type including The Art of SpeedReading People and the one-million copy best-seller Do What You Are. A jury consultant for twenty-five years, Paul pioneered the use of Personality Type to help trial attorneys understand and communicate with jurors and has worked on dozens of high profile civil and criminal cases including the first physician-assisted suicide trial of Dr. Jack Kevorkian. Paul holds a BS degree in Psychology and an MS in Organizational Behavior.