When I start talking about Phineas Gage, a number of people will say "oh, yeah isn't that the guy with the iron bar in his head?"
To which I add: yes, and he is the medical case that helps strengthen my contention, from 17 years of working with young adults, that adolescents are brain damaged.
A bit about Phineas Gage for the uninitiated, from the superb young adult book Phineas Gage: A Gruesome but True Story About Brain Science, by John Fleischman:
Phineas Gage was the foreman of an explosives crew that blasted apart rock formations that blocked proposed railroad paths. Back then, the choice of explosives was far more limited than the more stable compounds-such as dynamite-that would later come into use. Back then, if you wanted to blow up part of a mountain to make way for a railroad, your only choice was black powder, which ranks among the most unstable of explosives; the slightest spark can set it off.
To really understand what happened to Gage, it's best to know exactly how an explosives crew operated back then.
First the crew would drill a hole in the rock. Then, the powder man would (very gently) pour the black powder into th"e hole. Next, the tamping man (Gage's job, and I'll get to what "tamping" means in a moment") would very gently poke a hole into the black powder, so that the fuse man could place the fuse in the black powder. Still, however, the explosives needed to be packed into the hole.
It is at this point that we need to discuss the tamping man's job in a bit more detail. In particular, we need to discuss the tool a tamping man used for his job. It was a thirteen foot iron rod, which had a point on one end (imagine a thirteen foot iron pencil, and you get the idea). Now, as was said before, the tamping man's first job was to (carefully, oh, so carefully) stick the pointy end into the exposed black powder to make a hole for the fuse.
He did this carefully because, of course, an iron bar carelessly placed in a granite hole strikes sparks.
By now, you're probably beginning to see what's coming.
But first, a bit about the sandman. The sandman's job was to fill the hole with sand. This, in turn, allowed the tamping man-who, you will remember, had poked that small hole in the black powder-to do his second job. Once the sandman had surrounded the fuse with sand and put a good sized layer of sand between the black powder and the hole's entrance, the tamping man, by inserting the rounded part of his iron into the hole, would pack ("tamp") the explosives. Yes, it would strike sparks, but the sand prevented the sparks from hitting the black powder.
So now imagine that is September 13, 1848, and Phineas Gage is using that thirteen foot tamping rod, with the pointy side facing him, to pack those explosives into that hole. Imagine all of those sparks.
And now imagine what would happen if, on this day, the sandman forgot to put sand into one of those holes.
In the instant that the black powder exploded, the tamping rod shot out of the hole as if fired from a cannon. The rod entered Gage's head just below his left cheekbone, came out the top of his head, and clanged to the ground several feet from the site of the explosion.
In computer reconstructions of the accident, it becomes evident just how extraordinary Gage's injury was. Had the bar gone through just a millimeter in one direction of the other, it would have clipped major blood vessels, or areas of the brain that dealt with key bodily functions, and Gage would have died immediately.
But no. As witnesses reported, Gage didn't even lose consciousness. He sat up, with blood running down his face (obviously), and just started talking about the explosion. His stunned explosives crew piled him onto a cart, where he made a point of making an entry in the foreman's time book.
Within ten weeks, Gage was back at work, and except for scars at the entry and exit points and the loss of vision in his left eye, he was fully recovered.
But he was no longer Phineas Gage.
In addition to a number of subtle difficulties in mathematical judgement, Gage had completely lost his ability to control himself. He cursed constantly and with no consideration of the people (and children) around him; he got into fights; and he often began one task, abandoned it, and then moved to another.
He soon lost his job at at the railroads, and worked various odd jobs until his death.
But let's go back and consider that injury.
When that tamping rod plowed through Gage's head, it took with it a good portion of the front of his brain. This part, called, appropriately, the frontal lobe, is generally considered to be the most recent part of the brain in evolutionary terms. Generally speaking, the frontal lobe is the part of the brain that considers the impulsive thoughts of the hippocampus-the almond sized, primitive component at the very center of the human brain-and says "wait a minute...maybe that impulse to get my face tattooed with a four-color dragon is a bad idea."
Now imagine a life in which that part of the brain is gone.
Or, to put it another way, imagine the brain of an adolescent.
Because, generally speaking, the adolescent brain is pretty much a brain without frontal lobes.
Oh, it works occasionally, but as any neural scientist can tell you, the frontal lobes of teenagers just don't work as well as those of an adult. In fact, you can find out more about the sluggish frontal lobes of teenagers in this story, courtesy of NPR. Basically, it discusses how the frontal lobes of teenagers just can't talk to the rest of the brain the way an older person's frontal lobes can; in other words, it discusses how teenage brains function as if the front part has been obliterated by a tampting rod plowing through it after a massive black power explosion.
So that's it. As I often tell my students, if you're a teenager, you're brain damaged. Your frontal lobes aren't working. If you do stupid stuff, as I did when I was a wee slip of a lad, it's not because you're a bad person. It's because you're brain damaged.
And that's not just the ramblings of a jaded brown belt librarian. That's science.
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