Should It Be Illegal for Those Under 21 To Join the Military?

I've traveled to a lot of countries that have, in the past, been accused of exploiting child soldiers. Many times these children are forcibly taken from their parents. But child soldiers can also be lured into joining the ranks of soldiers because its perceived much like any other gang....its a family, a broken family that provides a certain amount of freedom, power, and respect.

Child soldiers are supposedly good soldiers. They do what they are told, are easily persuaded and manipulated, quickly develop into good marksmen, and are smaller targets for the enemy.

Leaving aside the conversation about the ethics of an army built on conscription, at what minimum age should volunteers be allowed in an army? In the United States, applicants may join at 17 with a parent's permission but face delayed entry. Most applicants start their training at the minimum age of 18.

However, recent studies have shown that human brains do not fully develop until our early 20's. The prefrontal cortex, which "controls impulses, calm emotions, [and] provide an understanding of the consequences of behavior and allow reasoned, logical, and rational decision making processes" "do not fully develop until the early twenties."
-The International Justice Project, citing other academic research projects.

Instead, adolescents use a different part of their brain: the amygdala, which is "typically associated with emotional and gut responses."

"Studies by Dr. Deborah Yurgelun-Todd and her colleagues at Harvard Medical School using functional MRI scans show that teenagers when interpreting emotional information use this part of the brain rather than the rational decision making region: the prefrontal cortex. Conversely, adults in the same experiment relied more heavily on the frontal cortex. In assessing the results of the tasks set to the two groups, Dr. Yurgelun-Todd found that all of the adult participants interpreted the emotional information correctly in comparison to under half of the adolescents."
ibid.

Dr. Yurgelun-Todd says that "Adult brains use the frontal lobe to rationalize or apply brakes to emotional responses."

There are other parts of the brain that do not fully develop in adolescence including the corpus callosum, which are the axons that help both the left and right parts of the brain communicate.

The author(s) are careful not to suggest that this impedes an adolescent from knowing right from wrong. It does however, suggest that adolescents may have difficulty "controlling their desires", understanding the ramifications of their decisions, and perceiving their "time horizon" differently than adults so they are only concerned about the next 1-3 days whereas an adult engages in "long-term planning".

For more information, see:
http://www.internationaljusticeproject.org/pdfs/juvBrainDev.pdf

This suggests that an adolescent may make an emotional decision to enter the military and may be predisposed to make emotional decisions in combat once in the military. Rationality may have little force in decision making for many of the adolescents caught in the midst of combat. Combine this with stories of basic training where soldiers view battle scenes while listening to loud rock music and this suggests that the military knows about these emotional responses and deliberately manipulates young soldiers for its own ends.

Anecdotally, I have heard a soldier that remarked that he got caught up in the loud music and battle scenes and started hating Arabs (shown in the videos) until he took a step back and started processing that brainwashing. Other studies have shown that the military has made great strides in its training to psychologically help its soldiers be able to kill the enemy (The most helpful suggestion instead of an offensive command, is defensive: to protect your battle buddy).

With the development that has taken place in neuro-biology, should a new minimum age be considered for military service? Say 21?

Suggestions that the military is exploiting the most vulnerable and manipulating them for the military's own ends can be thwarted somewhat by raising the minimum age and by recruiting more soldiers from among the richer classes. Raising the minimum age would put rationality at the forefront and allow each volunteer to make sound decisions when joining the service and also in combat.

This would also perversely shut down the argument of soldiers that they should be allowed to drink alcohol at 18...since if they are able to fight and die for their country they should certainly be allowed to drink. Actually, both are harmful to brains that are still developing.