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:
• 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 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."