He can legally vote. He can kill. He can turn himself in. Maybe times change but when I was 18 people that age were fighting in wars, drinking legal in a lot of states, raising familys, running their own businesses. The only thing they couldn't do was vote at 18. People left home after high school and started their own lives. Some of us left at 16. I find science and real life at odds alot. Who is funding the studies is one way to see how results were achieved. I find kids in Alaska raised in the bush to be more advanced in a lot of areas then lower 48 city kids.  2 cents.