Several articles have recently appeared on the question of what age (or ages) should delineate the onset of adulthood for purposes of rights and responsibilities under the law. The outlets in which these articles have appeared include the New York Times, the American Psychologist, and the policy wonkish Governing magazine.
The emergence of these articles coincides with a currently pending U.S. Supreme Court case on whether it is constitutional to impose a life sentence for a crime other than murder that was committed as a juvenile. Beyond court cases, however, the issue of legal cut-off ages is fascinating and challenging in its own right. According to the Times article:
At the heart of the argument lies a vexing question: When should a person be treated as an adult?
The answer, generally, is 18 — the age when the United States, and the rest of the world, considers young people capable of accepting responsibility for their actions. But there are countless deviations from this benchmark, both around the world (the bar mitzvah, for instance), and within the United States.
For drinking, driving, fighting in the military, compulsory schooling, watching an R-rated movie, consenting to sex, getting married, having an abortion or even being responsible for your own finances, the dawn of adulthood in America is all over the place.
Among the factors complicating this debate is that different cognitive and behavioral abilities -- corresponding to different policy objectives -- may, on average, crystallize at different ages. The aforementioned American Psychologist article by Laurence Steinberg and colleagues contends, for example, that factual, logical abilities solidify earlier than impulse-control mechanisms.
One approach to addressing these challenges is to phase in legal rights gradually or contingent on parental approval. Examples include "graduated" driving privileges and the mimimum ages at which young people can marry.
I invite readers who have opinions on this topic to add comments to this posting!