Pyschobabble. I knew right from wrong WAY, WAY, WAY before age 18. That being said, the earlier post about some 30 year olds being juvenile is ALSO correct. So far, overall, the procedures in place for whether someone should stand trial as a competent adult have worked reasonably well. I've seen the cases of, for example, a Downs Syndrome sufferer being judged not able to stand trial, and of the opposite for some early teenagers. Example there would be the Columbine murderers - they killed people while executing a pre-mediated, extensive plan. You can't tell me they didn't know it was wrong. I don't care if they were under 18 or not, they deserved to be tried as adults, including the death penalty. Fortunately, we did not have to suffer through that trial.