They've crossed a brain threshold much earlier, that perhaps not at age 22 or 20, but even by age 15 or 16 you can begin to see the trajectory for development is quite different at the level of the brain, not at the level of behavior.
而且出现得很早， 并不是在22岁或20岁， 其实在15岁或16岁已经出现明显迹象， 发展轨迹大不相同， 这是从大脑发育来说的，而不是指行为方式，