According to recent research, the human prefrontal cortex – which is involved in functions such as decision-making – does not reach full maturity until nearly 30 years of age. This means that teenagers are not in full control of their actions, and this should be taken into account during sentencing. Teenage criminals, therefore, should be put into rehabilitation programs that attempt to curb bad behaviour.
Mills KL et al. Developmental changes in structure of the social brain in late childhood and adolescence. Soc Cogn Affect Neurosci 2012.