When prosecutors wanted a jury to understand what was going on inside the mind of Lawrence Russell Brewer Jr. when he dragged a black man to death near Jasper, Texas, they pointed to the outside of his body.
Jurors saw color slides of Brewer's extensive array of tattoos which included a pentagram, a burning cross, a swastika, the words "death before dishonor," and the symbol of a racist prison gang affiliated with the KKK.
Defense attorneys scoffed that no conclusions could be drawn from such an exercise, pointing out that a tattoo on Brewer's chest was the image of a female family friend he knew from church.
But prosecutors told jurors the tattoos were evidence of the depth of Brewer's white-supremacist convictions.
"It's one thing to say white- supremacist words. It's another to belong to a white-supremacist gang. It's one step further when you tattoo that message on your body. That's permanent," Jasper County District Attorney Guy James Gray told reporters during the trial in September.
Brewer was convicted of his crime and sentenced to death. But the prosecutorial strategy raises a more basic question: What can tattoos tell us about the personality of the wearer?
The idea has not been widely studied. The traditional psychotherapist would no more ask a patient about tattoos than about facial hair or shoe size. But recently, some psychiatrists have been looking more closely at what one calls the potential for "dermal diagnosis."
Dr. William Cardasis, a criminal psychiatrist in Michigan, last month presented research at a psychiatric conference in Baltimore suggesting a link between tattoos and the diagnosis of anti-social personality disorder.
That's the technical term for a sociopath -- someone who has no regard for the rights of others, who lies, steals, is impulsive, frequently runs afoul of the law, but suffers little or no remorse.
Cardasis, the study's lead investigator, found that among 55 patients at the maximum-security forensic hospital in Ann Arbor the likelihood of a diagnosis of anti-social personality disorder was far greater among patients with tattoos.
"The tattoos aren't making a diagnosis for you, but it was a strong indicator in this population," says Cardasis, who presented his findings at the annual meeting of the American Academy of Psychiatry & the Law.
Patients at a forensic hospital are hardly average citizens. They are usually criminal defendants whose sanity has been called into question. Typically, they have been judged not guilty by reason of insanity or incompetent to stand trial.
In other words, the presence of a tattoo on an average man's forearm doesn't necessarily mean the bearer is bad to the bone. (A good thing, too, because an estimated 1 in 10 Americans has a tattoo.) But Cardasis says his research does suggest that psychiatrists should be paying more attention to what a patient's skin is telling them.
"In the least, a clinician should ask what tattoos mean to a patient," he says. "There usually is a story behind them."
Cardasis found that a tattoo's message was not always easy to appreciate. Religious symbols such as a cross often hold no particular religious meaning to their owner. Aggressive symbols such as a skull and crossbones might mean little more than what appealed to the person when he was 17 and drunk.
"You see a tattoo with a spider's web and a bull's eye," says Cardasis. "You ask, 'That's quite a tattoo,' and it'll turn out to be where he shot heroin."
Dr. Gerald W. Grumet, a psychiatrist in Rochester, N.Y., who has studied the psychodynamics of tattoos, agrees that tattoos deserve greater attention from clinicians. He theorizes that from the earliest tattoo -- perhaps 8,000 years ago -- men and women have used body markings to establish personal identity.
"It can be an interesting little window into the soul," he says.
Grumet says that for many young people the tattoo is a "pictorial quest for self-definition," a kind of heraldry for the lower classes, that bolsters self-esteem and serves as a badge of unity for the outcast or outlaw.
Anti-social messages have long been a common theme. Tattooing "LOVE" on the knuckles of one hand and "HATE" on the other was a common practice among delinquent teens before the words popped up on Robert DeNiro's character in "Cape Fear."
But Grumet suspects that the link between anti-social personality disorder and tattoos in the general population is actually weaker now. Tattoos are much more mainstream, particularly for women who elect to have a butterfly drawn on an ankle or thigh.
"With women, a tattoo may not mean much more than a need to exhibit oneself," he says.
Former Secretary of State George Shultz has a tattoo (a Princeton Tiger, not in plain sight), as did Winston Churchill's mother. Mattel considered marketing a tattoo-sporting Barbie, but decided against it. Children can buy colorful transfers to stick on their bodies as "temporary tattoos."
Grumet notes that some past studies have tried to draw various conclusions about tattoos, linking them to a more positive body image in one research effort and to a greater feeling of machismo among military men in another.
One study of cadavers in New York City found a high incidence (20 percent) of tattoos among teen drug addicts.
But Grumet questions whether psychiatrists will ever be able to draw many conclusions from tattoos -- the significance of their presence, location on the body, or their symbolism -- other than to inquire, "What does that marking mean to you?"
Tattoo-industry officials are generally unimpressed by efforts to study the psychological implications of their work. Tattoo artists say the motivations of their customers usually aren't that easily discerned.
"Everyone is so individual," says Bud Yates, vice president of the National Tattoo Association of Allentown, Pa., which represents more than 1,000 tattoo artists and enthusiasts. "People use tattoos not only to express their feelings but to remember things, important moments in their lives. Often, they don't share that openly."
Yates, who owns three tattoo shops in Colorado Springs and Pueblo, Colo., says he has seen his business triple since the 1970s. His customers tend to be young and female. He refuses to tattoo a person's hands, neck or face -- since the inexperienced tend to stereotype such tattoos as "serial-killer territory."
Charles W. Eldridge, a tattoo artist and historian in Berkeley, Calif., says academic studies of tattoos are usually biased and draw subjects from a prison population. That is hardly typical of the tattoo industry's mainstream clientele, he says.
"It's an outsider's point of view," says Eldridge, 52, owner of The Tattoo Archive. "People will get a tattoo and not even be aware of its significance in the greater scheme. Just because someone gets the Grim Reaper doesn't mean he's into death and violence."
Eldridge has experience in this. Tattoos cover three-quarters of his body. But even as his profession has gone mainstream, he thinks too many people still embrace the stereotype of the tattooed man as a gang member or thug.
"Tattoos are mile markers in people's lives, a scrapbook," he says. "A tattoo does speak about a person, but exactly what it's saying can be a mystery."