http://edition.cnn.com/2007/HEALTH/12/28/teen.brain/

Expert: Teen brain key to understanding criminal behavior

• Story Highlights
• Latest research shows brain continues to develop to age 25 and beyond
  
• Teen brains lack impulse control, sophisticated reasoning capability
  
• Some advocates say teens should be judged differently in criminal justice system.
  
• Supreme Court in 2005 outlawed death penalty for crimes committed before 18
  
• Next Article in Health »
  
  

NEW YORK (AP) -- The teenage brain, Laurence Steinberg says, is like a car with a good accelerator but a weak brake. With powerful impulses under poor control, the likely result is a crash.

Dr. Jay Giedd of the National Institutes of Health says the brain continues to mature up to age 25 or later.

And, perhaps, a crime.

Steinberg, a Temple University psychology professor, helped draft an American Psychological Association brief for a 2005 case in which the U.S. Supreme Court outlawed the death penalty for crimes committed before age 18.

That ruling relies on the most recent research on the adolescent brain, which indicates the juvenile brain is still maturing in the teen years and reasoning and judgment are developing well into the early to mid 20s. It is often cited as state lawmakers consider scaling back punitive juvenile justice laws passed during the 1990s.

"As any parent knows," wrote Justice Anthony Kennedy for the 5-4 majority, youths are more likely to show "a lack of maturity and an underdeveloped sense of responsibility" than adults. "These qualities often result in impetuous and ill-considered actions and decisions."

He also noted that "juveniles are more vulnerable or susceptible to negative influences and outside pressures, including peer pressure," causing them to have less control over their environment.

Some child advocates have pointed to the Supreme Court decision and the research as evidence that teens -- even those accused of serious crimes -- should not be regarded in the same way as adults in the criminal justice system.

Dr. David Fassler, a psychiatry professor at the University of Vermont College of Medicine who has testified before legislative committees on brain development, says the research doesn't absolve teens but offers some explanation for their behavior.

"It doesn't mean adolescents can't make a rational decision or appreciate the difference between right and wrong," he said. "It does mean, particularly when confronted with stressful or emotional decisions, they are more likely to act impulsively, on instinct, without fully understanding or analyzing the consequences of their actions."

Experts say that even at ages 16 and 17, when compared to adults, juveniles on average are more:

•impulsive.

•aggressive.

• emotionally volatile.

• likely to take risks.

• reactive to stress.

• vulnerable to peer pressure.

• prone to focus on and overestimate short-term payoffs and underplay longer-term consequences of what they do.

• likely to overlook alternative courses of action.

Violence toward others also tends to peak in adolescent years, says psychiatrist Dr. Peter Ash of Emory University. It's mostly likely to start around age 16, and people who haven't committed a violent crime by age 19 only rarely start doing it later, he said.

The good news here, he said, is that a violent adolescent doesn't necessarily become a violent adult. Some two-thirds to three-quarters of violent youth grow out of it, he said. "They get more self-controlled."

Some of the changes found in behavioral studies are paralleled by changes in the brain itself as youths become adults.

In fact, in just the past few years, Steinberg said, brain scans have given biological backing to commonsense notions about teen behavior, like their impulsiveness and vulnerability to peer pressure.

It's one thing to say teens don't control their impulses as well as adults, but another to show that they can't, he said. As for peer pressure, the new brain research "gives credence to the idea that this isn't a choice that kids are making to give in to their friends, that biologically, they're more vulnerable to that," he said.

Consider the lobes at the front of the brain. The nerve circuitry here ties together inputs from other parts of the brain, said Dr. Jay Giedd of the National Institute of Mental Health.

This circuitry weighs how much priority to give incoming messages like "Do this now" versus "Wait! What about the consequences?" In short, the frontal lobes are key for making good decisions and controlling impulses.

Brain scans show that the frontal lobes don't mature until age 25, and their connections to other parts of the brain continue to improve to at least that age, Giedd said.

The inexplicable behavior and poor judgments teens are known for almost always happen when teens are feeling high emotion or intense peer pressure, conditions that overwhelm the still-maturing circuitry in the front part of brain, Giedd said.

As Steinberg sees it, a teenager's brain has a well-developed accelerator but only a partly developed brake.

By around 15 or 16, the parts of the brain that arouse a teen emotionally and make him pay attention to peer pressure and the rewards of action -- the gas pedal -- are probably all set. But the parts related to controlling impulses, long-term thinking, resistance to peer pressure and planning -- the brake, mostly in the frontal lobes -- are still developing.

"It's not like we go from becoming all accelerator to all brake," Steinberg said. "It's that we go from being heavy-foot-on-the-accelerator to being better able to manage the whole car."

Giedd emphasized that scientists can't yet scan an individual's brain and draw conclusions about how mature he is, or his degree of responsibility for his actions.

Brain scans do show group differences between adult and teen brains, he said, "but whether or not that should matter (in the courtroom) is the part that needs to be decided more by the judicial system than the neuroscientist."

Steinberg, who frequently testifies on juvenile justice policy and consults with state legislators on the topic, said it's not clear to him how much the research on teen brains affects lawmakers. They seem more swayed by pragmatic issues like the cost of treating teens as adults, he said. But he noted that he has been asked to testify more in the past few years than before.

In any case, experts say, there's nothing particularly magic about the age 18 as a standard dividing line between juveniles and adults in the courtroom.

Different mental capabilities mature at different rates, Steinberg notes. Teens as young as 15 or 16 can generally balance short-term rewards and possible costs as well as adults, but their ability to consider what might happen later on is still developing, he said.

A dividing line of age 18 is better than 15 and not necessarily superior to 19 or 17, but it appears good enough to be justified scientifically, he said.

Steinberg said he thinks courts should be able to punish some 16- or 17- year olds as adults. That would be reserved for repeat violent offenders who've resisted rehabilitation by the juvenile justice system, and who could endanger other youth in the juvenile system if they returned. "I don't think there are a lot of these kids," Steinberg said.

For the rest, he thinks it makes sense to try rehabilitating young offenders in the juvenile justice system. That's better than sending them through the adult system, which can disrupt their development so severely that "they're never going be able to be a productive member of society," Steinberg said. "You're not doing society any favor at all."

Ash said that to decide whom to treat as an adult, courts need some kind of guideline that combines the defendant's age with the crime he's accused of. That should leave room for individual assessments, he said.

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But "we don't have very good measuring sticks" for important traits like how impulsive a juvenile is, he said.

In any case, the decision for each defendant should balance a number of reasons for punishment, like retribution, protecting society, deterring future crime, and rehabilitation, said Ash, who's a member of the American Psychiatric Association's Committee on Judicial Action.

Even if a 14-year-old murderer is held morally responsible for the crime, he will have matured by the time he's 18, and in the meantime he may be more amenable to rehabilitation than an adult murderer is, Ash said.

In fact, most experts conclude that rehabilitation works better for juveniles than for adult offenders, he said.

And just as parents know how irrational juveniles can be, Ash said, they also know that rehabilitation is a key goal in punishing them.

"What we really want," he said, "is to turn delinquent kids into good adults." E-mail to a friend

Mom hopes incarcerated son will be freed

By SHARON COHEN, AP National Writer
Sun Dec 9, 12:40 AM ET

Every month or so, Missy Phillips makes a four-hour drive to visit her son in prison, refusing to accept that his fate has been sealed — and he will die behind bars. Joshua, just 23, is serving a life-without-parole sentence in Florida for a ghastly crime — the bludgeoning and stabbing of his 8-year-old neighbor, Maddie Clifton. He's nearing the end of what could be the first of many decades behind bars.

But his mother doesn't see it that way.

"We talk in terms of when he gets out, not if," Phillips says. "I have to keep some semblance of hope for both of us. I don't know how it's going to happen. I do believe that someday he will walk out of there. I can't go the other way."

Joshua Phillips was just 14 in November 1998 when Maddie, who lived across the street in Jacksonville, disappeared. He joined in the massive search for her. Police were even at his house for routine questioning. About a week later, Missy Phillips made a horrifying discovery: She noticed a wet spot near her son's water bed, pulled aside the frame and saw Maddie's feet.

Police said Joshua Phillips confessed, claiming he beat Maddie with a bat and repeatedly stabbed her in a panic to stop her screams after he accidentally hit her with a baseball. Prosecutors cast doubt on that story.

Phillips says she has repeatedly begged her son for an explanation, but has never received one.

"I used to plead, 'Josh, I found Maddie in our home. I think I deserve to know what happened,' " she says. "He won't discuss it with me. I had to learn how to step back ... and say I may never know."

Phillips, now 52, had done her own soul-searching over the years.

"I think every mother who has a tragedy of this magnitude — certainly early on, you question yourself: Did I miss something? Did I do something wrong?" she says. "Every mother who loves her child feels a responsibility. ... He's told me more than once, 'It's not anything you did or didn't do.' "

A year after the murder, Phillips says she approached Maddie Clifton's mother and they have spoken several times. And when Phillips' husband, Steve, was killed in a car accident in 2000, the girl's mother, Sheila, visited to offer her condolences. "She's a kind person," Phillips says.

Phillips has remarried — she met her British husband after he read about her son's case on the Internet and she has taken his name, though she prefers not to make it public. She says she moved twice to stay anonymous as she presses for a new trial for her son, claiming his attorney was incompetent.

She maintains her son's sentence is excessive.

"They should have some alternative way of dealing with juveniles in serious situations so they don't get their lives thrown away," she says. "That's what the state says — my son's life is worthless. Just throw away the key."

State Attorney Harry Shorstein, who prosecuted Joshua as an adult, says his case — and those of other juvenile lifers — should be reviewed at some point and the possibility of release considered if appropriate.

Phillips tries to be upbeat, but admits her resolve sometimes wavers.

"I'm human," she says. "I have my moments, my worries and my doubts."

As much as her son dominates her thoughts, she says when she sees a little girl with her family, she is haunted by memories of Maddie Clifton.

"Of course, I'm mindful of Maddie not being here," she says. "As close as I am to this tragedy, I can't say I know their pain anymore than they know mine. .. I think of them a lot. I think of Maddie a lot. ... I'll carry this with me until I die."

Harsh crimes, hard time: when juveniles are sentenced to life without parole

EDITOR'S NOTE -- What does it mean to send a kid criminal away for life, and is it just? This is another in a series of stories on a growing effort to reform penalties against juvenile offenders.

By ADAM GELLER

AP National Writer

DETROIT (AP) -- It began as a feud only a child could invent -- teenage chest-thumping over who had the right to sneak across the golf course at Germania Town & Country Club after dark and scoop lost balls out of a pond.

But by the time it ended in the pre-dawn blackness of a long-ago June morning, that juvenile bravado had exploded into a crime whose horror defied adult comprehension.

Buried inside the charred skeleton of a Saginaw home, three children -- 7-year-old Isaac Rollie and his 9- and 11-year-old sisters -- lay dead. They perished at the hands of two local teens, who hurled pop-bottle firebombs through the windows of the house on Jordan Street so one could settle a petty score.

For taking three innocent lives, a judge decided, Michael Lee Perry had to pay. Perry was 16 at the time of the fire, but for an adult crime he'd have to do adult time -- and spend the rest of his life in prison, without any chance for parole.

That was 17 years ago. And today, when Perry rises and offers his hand to a visitor allowed inside the razor wire-topped brick of Detroit's Mound Correctional Facility, it is clear that prisoner No. 217645's claim on childhood has long since lapsed.

He stands 6-foot-2, graying at the temples, his hairline receding. No question, Perry is a man now.

He appeals, though, for the understanding he says the boy he once was still deserves.

"I was wrong. I took people's lives who didn't even have a chance to grow up and experience life. But, I mean, I didn't even experience life myself,'' says Perry, now 34. "I'm not saying a child should go unpunished. ... (But) it's like I'm just abandoned, discarded, left for nothing.''

Perry is far from alone.

At least 2,381 people are serving life without parole in U.S. prisons for crimes when they were 17 or younger. The vast majority are locked up because they took another life.

Ever since the U.S. Supreme Court ruled in 2005 that sentencing juveniles to death is unconstitutional, advocates have been nudging lawmakers, courts and the public to go one step further and re-examine the life sentences meted out to young people convicted of the most serious crimes.

If we believe that juveniles are intrinsically different from adults -- that their judgment is lacking, that they are capable of learning from mistakes -- then how can we justify locking them away forever?

It is a difficult question and a painful one to contemplate. Some of the crimes are horrific. Others seem downright senseless. The age of the perpetrators -- and often of their victims -- is enough to make any mother or father say a quiet prayer.

Then there is the fact that laws stringently tightened in recent years often give judges and juries little or no choice in weighing punishment. In many states, the severity of the crime, not the age of the accused, mandates trial and punishment as an adult.

Even when some measure of discretion is allowed, it can distort the choices.

When the time came to sentence Michael Perry, state law forced a judge to decide between widely disparate options. He could treat Perry as a juvenile, despite the seriousness of the crime, and see him released by 21. Or he could send him away forever.

"The only conclusion that I can reach,'' Judge Leopold Borrello told two grieving families gathered in the courtroom that day, "is that the law deprives me of doing justice.''

------=

Quantel Lotts was 14. He and his brothers were spending the weekend at a friend's house in St. Francois County, Mo., and Quantel and his stepbrother Michael Barton started fighting. Quantel chased Michael -- who was three years older -- with a bow and arrow before an adult stepped in. Not long after, while they snacked, one of the younger children noticed Quantel holding a knife and reported him to Michael.

"Let's take this outside,'' Michael told Quantel. In the yard, their shoving match ended in Michael's death.

Quantel says he turned down an offer to plead to second-degree murder just before his trial began. Found guilty, he was sentenced to life without parole.

Today, speaking by telephone from prison, Quantel Lotts will not talk about what happened that day. But he remembers clearly where it left him.

"They say my stepbrother's dead and they say I killed him,'' he says. "When I first got locked up, I spent the first six months crying to myself every night.''

------=

Americans are firm believers in stiff punishment. But U.S. courts long applied a more forgiving standard when the accused was a juvenile.

Then in the late 1980s and early 1990s, alarm over violent youth crime set off widespread fears. Tales of brutal carjackings and brazen gang warfare, of remorseless kids who killed just to know what it felt like, filled headlines.

Soon, experts warned, we would be at the mercy of legions of juvenile "superpredators.'' In state after state, lawmakers and prosecutors decided to get tough.

Many states began requiring that juveniles accused of first-degree murder be tried as adults. To show they meant business, lawmakers mandated stiffer punishments. If you were convicted of murder, no matter how old, you were going to do life.

The new mind-set resulted in swift change. In 1980, just two juveniles were sentenced to life without parole, the harshest punishment possible short of the death penalty. By 1996, 152 youth offenders were sent to prison for life, according to figures compiled by Human Rights Watch and Amnesty International.

Today, inmates in 39 states and the federal prisons are serving life without parole for crimes they committed as youngsters. Five states -- Pennsylvania, Louisiana, Michigan, Florida and California -- account for two-thirds of the cases documented by the two human rights groups, which are pushing for reform.

The tougher laws were applauded by prosecutors and victims' advocates as necessary tools to fight crime and protect the public.

"If they can do these kinds of crimes, then they've got to face the punishment,'' says Maggie Elvey, a California activist whose husband, Ross, was beaten to death in 1993 by two boys, ages 15 and 16.

"My theory is when Ross can walk the face of the Earth again, that's when you can get out,'' Elvey says.

But the sharp rise in juvenile violence that the new laws were meant to fight never came. Gradually, that has led some to question whether the tougher approach went too far.

"There were all kinds of predictions (of a sharp rise in juvenile violence). I think I even made a few. But that hasn't panned out,'' says Linda J. Collier, a dean at Delaware County Community College in Media, Pa., among those who called for stiffer juvenile sentences. "There are probably many cases where I'd say, 'Yes, lock them up and throw away the key.' But there are probably other cases where that kid, if you look into his eyes, if you look into his soul, you can say yes, they can be rehabilitated.''

But how to do that? Should life without parole be eliminated for all juvenile offenders or only for some of them? What should the alternative be?

The questions get harder when they are applied to real lives rather than abstracts.

Addolfo Davis was only 14, but he'd already known plenty of trouble -- the child of a crack addict, he'd been arrested for shoplifting, robbery and other offenses starting when he was 10. His grandmother rejected a child welfare agency's recommendation that he be removed from her home, then watched as he beat his own head until it bled and burned himself with cigarettes.

Then, in October 1990, Davis joined two other teens -- one 16, the other 18 -- in something far worse. Angered because of a dispute over drug-sales territory, they set out to even a score. The trio, all carrying guns, headed to the third-floor apartment of a rival, and when it opened, pushed inside.

Davis didn't get far. One of the men inside knocked his gun away immediately and ran. But Davis' companions began shooting, killing two of those inside and wounding two others.

After he was arrested, Davis was transferred to adult court, in part because of his prior record. When he was convicted of murder -- found accountable although he hadn't fired a shot -- the law made it clear he would be sentenced to life. Today, he is 31.

"Gun towers, bars, walls, lock downs, hand cuffs, visits, letters, collect calls,'' he wrote for an assignment in a prison ministry class two years ago. "This is all I know.''

------=

On a Sunday night in 1994, the kitchen staff at Bistro Pete's was too busy to notice the restaurant's back door had been left unlocked. Suddenly, two masked figures barged into the suburban Sacramento eatery. They waved guns, and barked orders. Moments later, kitchen manager David Lamburth lay dying.

Police arrested three 17-year-olds. The shot that killed Lamburth, they said, was fired by Dwayne "Tommy'' DeLuna. At trial, DeLuna acknowledged his role but claimed the shooting was an accident.

"Show some mercy. Consider his age. I know what's in his heart,'' DeLuna's mother pleaded with the judge, after he was found guilty. "He is a good kid.''

But the victim's mother begged to differ. "He's dead. You did it. When you shot my kid, Tommy, you shot me, too.''

In weighing punishment, a judge told DeLuna the legal system had already shown mercy. If he'd been a few months older at the time of the shooting, he could've faced execution. Instead, with five months left in his childhood in the eyes of the law, he was sentenced to life without parole.

------=

Sending juveniles to prison for life raises a host of tough questions. Colorado tangled with them last year when lawmakers made juvenile lifers eligible for parole after 40 years and the governor established a special clemency board to look at those already in prison. Legislators in Illinois and California have introduced bills calling for change.

Now, Michigan -- where 306 inmates are serving life for crimes they committed when they were 17 or younger -- could be the next to face those questions.

At least that is the hope of Deborah LaBelle, an Ann Arbor attorney pushing for reform. She lambastes the inconsistencies of a legal system that deems people too immature to vote or drink alcohol or serve on juries, but says they are old enough to be held accountable as adults for their crimes. Worse, she says, is that mandating life sentences forces courts to treat all youth convicted of murder the same.

"Aren't there kids who have done horrible things? Yes. But then you have to grant that aren't there kids who didn't, who just made a horrible decision,'' she says. "Shouldn't we individualize them? Aren't they at least entitled to that?''

LaBelle's files are filled with dozens of such stories.

Some echo the "poster child'' cases highlighted by advocates -- tales of teens who, at least in the retelling, are guilty of being in the wrong place at the wrong time. Often, they acted as accomplices but didn't pull the trigger, or committed crimes at the behest of someone older.

But the debate is crystallized in the cases that force hard choices -- harsh sentences vs. harsh crimes.

They are stories like Trevor Brownlee's, who admonishes himself -- 18 years too late -- for his days as a teenage drug dealer on the streets of Ypsilanti. In 1989, when Brownlee was 15, he and two friends set out for a party. Local gangs were feuding. Underneath his trenchcoat, Brownlee carried a sawed-off shotgun.

It wasn't long before Brownlee's group ran into teens they'd never seen before, in from Detroit. Soon, they started trading words over turf. The confrontation seemed to fizzle. Then, Brownlee's friend shouted an alarm: Was one of the out-of-towners reaching for a gun?

Brownlee didn't wait to find out. He fired into the Detroit teens' car, then shot one in the torso, another in the leg. The first was killed. The second was paralyzed from the waist down.

Today, Brownlee wears No. 211016 on the state blues issued to prisoners at Riverside Correctional Facility in Ionia, where he is serving life. The sentence has given him plenty of time to think about that night. What troubles him goes beyond knowledge that he killed someone. It's that, in his words, the crime was "about nothing.''

"It wasn't until I was 25 that I actually sat down and realized the full extent of what I did,'' says Brownlee, now 33. "Man, I was an idiot. That's the best way to describe it.''

Brownlee and others like him hope Michigan lawmakers see that they can learn and change, that they are worthy of a second chance. But backers of life without parole sharply disagree.

They're people like Michael Thomas, the prosecutor in Saginaw, whose strong support for juvenile life sentences is based on personal experience. Years of violent juvenile crime have defiled his hometown, making clear the need to protect the public and see that justice is done, he says.

"I think most people sitting on a jury, most people with houses in your neighborhood, pretty much understand that they (juveniles accused of heinous crimes) are the worst of the worst and that the penalty does fit the crime,'' he says.

------=

On the day Michael Lee Perry was sentenced for the Saginaw firebombing, the judge sought a middle ground that did not exist.

Instead, he sentenced Perry to life, while recommending that after 20 years a Michigan governor consider him for a reprieve, commutation or pardon.

Perry is already preparing his petition for freedom.

"When I go see Michael he gives me hope that everything will be better when he comes home,'' his mother, Maria Chavira, says.

But Perry recognizes that political calculus makes exoneration rare. Even as he reassures his mother, he tries to makes peace with the possibility that will never happen.

"If I do (spend) my life within these walls and fences, I'll accept my punishment,'' he wrote the judge two years ago, in a letter intended for the family of his victims, "and do it in the memory of the pain, suffering, heartaches and deaths I helped cause.''

"I will never forget.''

AP-ES-12-08-07 1215EST

Scientists say teen brain, still maturing, is key to understanding behavior

Scans show that the brain doesn't mature until age 25; increasingly, courts are considering such findings as they decide what punishments fit teen crime.

By Malcolm Ritter
ASSOCIATED PRESS
Sunday, December 09, 2007

NEW YORK — The teenage brain, Laurence Steinberg says, is like a car with a good accelerator but a weak brake. With powerful impulses under poor control, the likely result is a crash.

And, perhaps, a crime.

Steinberg, a Temple University psychology professor, helped draft an American Psychological Association brief for a 2005 case in which the U.S. Supreme Court outlawed the death penalty for crimes committed before age 18.

That ruling relies on the most recent research on the adolescent brain, which indicates the juvenile brain is still maturing in the teen years and reasoning and judgment are developing well into the early to mid-20s. It is often cited as state lawmakers consider scaling back punitive juvenile justice laws passed during the 1990s.

"As any parent knows," wrote Justice Anthony Kennedy for the 5-4 majority, youths are more likely to show "a lack of maturity and an underdeveloped sense of responsibility" than adults. " These qualities often result in impetuous and ill-considered actions and decisions."

He also noted that "juveniles are more vulnerable or susceptible to negative influences and outside pressures, including peer pressure," causing them to have less control over their environment.

Some child advocates have pointed to the Supreme Court decision and the research as evidence that teens — even those accused of serious crimes — should not be regarded in the same way as adults in the criminal justice system.

Dr. David Fassler, a psychiatry professor at the University of Vermont College of Medicine who has testified before legislative committees on brain development, says the research doesn't absolve teens but offers some explanation for their behavior.

"It doesn't mean adolescents can't make a rational decision or appreciate the difference between right and wrong," he said. "It does mean, particularly when confronted with stressful or emotional decisions, they are more likely to act impulsively, on instinct, without fully understanding or analyzing the consequences of their actions."

Experts say that even at ages 16 and 17, when compared to adults, juveniles on average are more impulsive, aggressive, emotionally volatile, reactive to stress and vulnerable to peer pressure. They also are more prone to focus on and overestimate short-term payoffs and underplay longer-term consequences of what they do. And they're more likely to overlook alternative courses of action.

Violence toward others also tends to peak in adolescent years, says psychiatrist Dr. Peter Ash of Emory University. It's mostly likely to start about age 16, and people who haven't committed a violent crime by age 19 only rarely start doing it later, he said.

The good news, he said, is that a violent adolescent doesn't necessarily become a violent adult. About two-thirds to three-quarters of violent youth grow out of it, Ash said. "They get more self-controlled."

Some of the changes found in behavioral studies are paralleled by changes in the brain itself as youths become adults. In fact, in just the past few years, Steinberg said, brain scans have given biological backing to common-sense notions about teen behavior.

It's one thing to say teens don't control their impulses as well as adults, but another to show that they can't, he said. As for peer pressure, the new brain research "gives credence to the idea that this isn't a choice that kids are making to give in to their friends — that biologically, they're more vulnerable to that," he said.

Consider the lobes at the front of the brain. The nerve circuitry there ties together inputs from other parts of the brain, said Dr. Jay Giedd of the National Institute of Mental Health.

This circuitry weighs how much priority to give incoming messages such as "Do this now" versus "Wait! What about the consequences?" In short, the frontal lobes are key for making good decisions and controlling impulses.

Brain scans show that the frontal lobes don't mature until age 25, and their connections to other parts of the brain continue to improve until at least that age, Giedd said.

The inexplicable behavior and poor judgments teens are known for almost always happen when teens are feeling powerful emotions or intense peer pressure, conditions that overwhelm the still-maturing circuitry in the front part of brain, Giedd said.

Giedd emphasized that scientists can't yet scan an individual's brain and draw conclusions about how mature he is, or the degree of responsibility he takes for his actions.

Brain scans do show group differences between adult and teen brains, he said, "but whether or not that should matter (in the courtroom) is the part that needs to be decided more by the judicial system than the neuroscientist."

There's nothing particularly magic about age 18 as a standard dividing line between juveniles and adults in the courtroom. Different mental capabilities mature at different rates, Steinberg notes. Teens as young as 15 or 16 can generally balance short-term rewards and possible costs as well as adults, but their ability to consider what might happen later on is still developing, he said.

A dividing line of age 18 is better than 15 and not necessarily superior to 19 or 17, but it appears good enough to be justified scientifically, he said.

Steinberg said he thinks courts should be able to punish some 16- or 17-year olds as adults. That would be reserved for repeat violent offenders who have resisted rehabilitation by the juvenile justice system and who could endanger other youths in the juvenile system if they returned. "I don't think there are a lot of these kids," Steinberg said.

For the rest, he says it makes sense to try rehabilitating young offenders in the juvenile justice system. That's better than sending them through the adult system, which can disrupt their development so severely that "they're never going be able to be a productive member of society," Steinberg said. "You're not doing society any favor at all."

Most experts conclude that rehabilitation works better for juveniles than for adult offenders, Ash said. And just as parents know how irrational juveniles can be, he said, they also know that rehabilitation is a key goal in punishing them.

"What we really want," he said, "is to turn delinquent kids into good adults."

Additional material from Associated Press writer Sharon Cohen.