WASHINGTON – A 16-year-old might be quite capable of making an informed decision about ending a pregnancy, in consultation with an adult. But the same teenager may lack the maturity to be held to adult levels of responsibility if she commits a violent crime, according to new research.

“Adolescents likely possess the necessary intellectual skills to make informed choices about terminating a pregnancy but may lack the social and emotional maturity to control impulses,” said Laurence Steinberg, who led the study.

Steinberg, professor of developmental psychology at Temple University, added: “This immaturity mitigates their criminal responsibility.”

“It is very difficult for a 16-year-old to resist peer pressure in a heated, volatile situation,” Steinberg said. “Most times, there is no time to talk to an adult to inject some reason and reality to the situation. Many crimes committed by adolescents are done in groups with other teenagers and are not premeditated.”

Steinberg and co-authors recruited 935 participants (age group 10-30) to examine age differences in a variety of cognitive and psychosocial capacities.

The participants took different tests measuring psychosocial (emotional) maturity and cognitive ability to examine age patterns in numerous factors that affect judgment and decision-making.

The maturity measures included tests of impulse control, sensation-seeking, resistance to peer influence, future orientation and risk perception. The cognitive battery included measures of basic intellectual abilities.

There were no differences among the youngest four age groups (10-11, 12-13, 14-15 and 16-17) on the measures of psychosocial maturity.

But significant differences in maturity, favouring adults, were found between the 16- to 17-year-olds and those 22 years and older, and between the 18- to 21-year-olds and those 26 and older. Results were the same for males and females, the authors said.

In contrast, differences in cognitive capacity measures increased from ages 11 to 16 and then showed no improvements after age 16 – exactly the opposite of the pattern found in the psychosocial measures.

The findings appeared in the October issue of American Psychologist.