Photo: Hoang Xuan Pham/ University Communications

Elizabeth Cauffman is studying the connection between the maturity of judgement in adolescents and their legal accountability.

IRVINE — A 16-year-old might be capable of making an informed decision about whether to end a pregnancy but lack the emotional maturity to be held as responsible as an adult for a violent crime, according to a new study of adolescent judgment and decision-making.

The study shows that teens often lack the social and emotional maturity to control impulses. In contrast, intellectual abilities such as logical reasoning reach adult levels long before psychosocial maturity is achieved.

"Many crimes committed by adolescents are done in groups and not premeditated. It's difficult for a 16-year-old to resist peer pressure and fully appreciate the riskiness of dangerous situations," said Elizabeth Cauffman, study co-author and UC Irvine psychology and social behavior associate professor.

"But they're able to understand and weigh options when it comes to medical decisions, which rarely are made on the spur of the moment and frequently involve consultation with adults."

Study participants, ranging in age from 10 to 30, completed interviews and questionnaires measuring psychosocial maturity and basic intellectual skills, including verbal fluency and working memory. Maturity was gauged by impulse control, sensation-seeking, resistance to peer pressure, risk perception, and awareness of long-term consequences.

Researchers found that certain cognitive abilities reach adult levels by the age of 16, while emotional maturity isn't attained till after 22.

The study appears in the October issue of American Psychologist, a journal of the American Psychological Association. The organization previously had described adolescents as being competent to make sound healthcare decisions but too shortsighted and impulsive to warrant capital punishment.

In November, the U.S. Supreme Court will hear two cases concerning the constitutionality of sentencing juveniles to life in prison without the possibility of parole.

"The Supreme Court may consider issues of adolescent cognitive and psychosocial maturity when looking at these cases," Cauffman said. "We believe adolescents' legal rights should be determined by evidence-based research on psychological and emotional development."

Led by Laurence Steinberg of Temple University, the study was also co-authored by Jennifer Woolard of Georgetown University, Sandra Graham of UCLA and Marie Banich of the University of Colorado at Boulder.

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