The human brain does not fully develop until it is two and a half decades old. So before a person blows out those twenty-five candles atop their gaudily decorated cake, they are functioning on, well, incompleteness. A fifteen-year-old’s wiring system is what they, themselves, would call wack. Inside their thick skulls, brain wires are searching for their connections in the hallows of the head. The mind's eye can’t tell if the diagram for how everything is supposed to work is upside down or right side up. The neuroscientists make use of their magnetic resonance imaging and observe and observe the prefrontal cortex of a teenage brain strain and strain to become more complex. These lab people, they run their fingers through their thinning hair, feeling the casing that holds their fully developed brain. “Hmm,” they say. “Riveting.” They look at pictures that they have been trained to understand and see that once the brain in the photo is not quite at the age to watch PG-13 movies, but old enough to understand what is going on in them, grey matter develops. The grey matter might as well be called thinking matter due to all of its neurons and their spindly branches. This causes some fifteen year olds to be able to develop ideas further, but parents normally just call it developing a smart mouth and not in the academic sort of way.

Observe fifteen year old girl #1, whose brain has been photographed every two years of her life since she was born. Considered an average fifteen-year-old she’s 6% I-can’t-believe-it’s-not-spandex pants, 5% low cut top that her parents don’t know about. 7% big sweater to put over shirt so parents won’t find out, 4% tattoo she drew on her hand because she wanted to see what it would look like, 8% test she just failed because she was picking flowers for her mom instead of studying, 6% homework she didn’t do because her mom told her to do it, 4% black nails to show rebellious nature, .6% actual rebelliousness, 2% item she just bought because she liked the salesgirl, 3% the chocolate she eats when she wants to, 10% real world, 6% something else, 7% brain mass, .4% brain mass to go before fully developed, and well, 30% undecided.

Now adults hate the undecided, especially neuroscientists. They study the not-fully-developed amydala for this lost portion of the teenage dilemma. As they search the developing part of the brain one lab person examines the evident differences in a teenager’s brain compared to an adult’s, and retorts that fifteen-year-olds might as well be another species. The adolescent center for emotions, the amydala, has become just as swelled as the fifteen-year-old’s eyes after she cries. The swollen amydala traffics the hormones who wear their thigh high boots, and commands the autonomic nervous system, affecting everything down to the toe tips. And thus, many factors of the amydala contribute to the behavior of fifteen-year-olds. Part of it is run by hormones. Part of it is run by logical neuron spindles. Part of it is run by rebelling. But most of it is run by this 30%, which in teenage years is controlled by gut-reactions.

Part of the limbic system, this amydala dips deeply into the emotion and as it develops it runs wild, and makes it perfectly logical to teenagers that they should make decisions dependent on what they feel. Often called a gut-reaction this is quite interestingly also found in the rats locked in their lab cages. It works like this: maybe something was said, maybe something was done, maybe something was not, but the amydala will react and suddenly the fifteen-year-old’s change as quickly as the impulses in their nerve cells pass by diffusion of a neurotransmitter. They go from saucy to sappy to sour to soulful to insane to inadequate to seventh heaven to tired to terrified to terrible to torturous and back to tired to joyful to jaded to degraded to depressed to surprised to sane just because of the amydala. The fifteen-year-olds will sometimes not know why they are feeling what they are; all they know is that they are feeling, feeling and experiencing at least something.

A common adult response to this fluctuation of emotion is to lecture the adolescents. But, this part of the brain can’t effectively be treated by lectures because a fifteen-year-old brain on average can only retain 5% by that way of teaching. Instead the amydala controls their actions because a teenager retains 70% of information by experiencing. The other 30% that they don’t or can’t retain just sits undecided in their mind and represents the answer to their most commonly asked question. Who am I?

Around the age of twenty-five, their brain snaps into fully complete mode. And with their fully loaded neurons spindles and practiced control of their amydala, which they have trained to mediate fear and gut-reactions because of their fear of gut reactions, these adults are able to define that space, define who they are, and suddenly, they believe themselves complete. And back in the lab, the man who has definitions for everything inside his skull cannot remember how it felt to be undefined. He stands in his starched lab coat, 5% glasses, 6% tweezers, 8% receptionist he never asked to coffee, 7% Harley he almost bought, 5% Nordstrom’s men’s counter where he almost picked up the purple tie, but got the grey one instead, 10% his cat Felix, 10% medical books, 5% novel he started writing in high school but never got around to finishing, 9% the cashmere socks he wears to bed every night, 5% the solitary place setting that is set at the table each evening, and 30% neuroscientist.

Scratching his head, he can’t remember what it was like without that last 30%. He seems to have forgotten his adolescence which is strange because he doesn’t recall having found anything on his scans that shows a problem with memory. But, instead of thinking of something he doesn’t have an explanation for, he tells himself once more how lucky he is that he doesn’t have children of his own. He walks over to the animal cages to see if the rats have developed cancer yet and seeing the abnormal lumps and growths that now cover the trapped rodents’ bodies he suddenly is overwhelmed with a tremendous inclination to let them all go. But just as his hand is reaching for the latch, he remembers that he is not undefined, that he is a neuroscientist, and this is not something a credible lab person would do, so instead he straightens himself up and blames the impulse on his fatigue caused by waking up in the middle of a REM cycle that morning.