Most of the time, when a large object passes through your skull, you will receive what is called a lethal injury. But for one person named Phineas Gage, that famously did not happen. And you don't survive and iron rod through your brain without psychologists paying attention, so his name can be found in basically every Intro to Psych class.

But if your story travels far and wide, chances are it doesn't get told right every time. So it's no surprise that the tale of Phineas Gage has become quite colourful, and inaccurate in most cases. But what's true is that he survived a seemingly unsurvivable injury and his stunning recovery helped settle some debates about how the brain works.

The first part of this story is usually told correctly. In 1848, Gage was 25, and a foreman helping lay railroad tracks in Vermont. He was using an iron rod three and a half feet long and over an inch wide to pack sand onto an explosive when it went off, firing the rod at his head. The rod entered his skull below his left eye, and then came out through the top of his head, landing about 30 yards behind him. He miraculously survived, but the doctor who first treated him reported that his friends said he was, quote, "no longer Gage." The injury had changed his personality.

And that's about where the story starts to spiral out of control. In some stories, Gage is described as becoming a monster of a man, a mean psychopath that could never function again in society. Some textbooks say that he never worked again, that he became a vagrant or a circus attraction. Or in one example, that he survived for 20 years with the rod still in his skull.

But pretty much none of that's true. We only have a few primary sources for Gage's life, and most are from the doctor who first treated him, an American physician named John Harlow. But those records suggest that in some ways, Gage recovered pretty quickly. Within four weeks of the accident, Harlow recorded that Gage's memory was as perfect as ever, for example. A visiting doctor wrote that a stranger would notice nothing peculiar about him. And six months later, Harlow wrote that Gage was fully recovered, though that might have been a little optimistic.

He later described Gage as being intellectually impaired. Nothing extreme, just a little slower at things. Like, Gage had previously been thought of as one of the best at his job and a shrewd, smart businessman. But some of his post-injury records suggest he became kind of average.

And it is true that he didn't get his old job back, though that probably wasn't due to a cognitive impairment, but rather because he became harder to work with. Reports suggest that after the accident, he lacked respect and kindness, was more profane, and got in more conflicts. In other words, he suffered a social impairment, at least at first. But he didn't become like a (?~2:54) wholly horrible person like some accounts suggest and he did, in fact, hold down a steady job later on.

Gage moved to Chile and worked as a carriage driver for years. Though not considered as high status as his old job as a foreman, it still required him to exercise social skills as well as cognitive and motor skills, and a doctor who knew him there described him as having, quote, "no impairment whatever."

So clearly he wasn't permanently unemployable or unable to function in society. It's likely that such larger than life stories of Gage arose in part through honest mistakes. Like the idea that he was a circus attraction may have arose because he likely made some paid appearances at Barnum's Museum in New York, which, though named for that same P. T. Barnum of Barnum & Bailey, was not part of any circus.

And it seems like some psychologists writing about him later on got his case mixed up with later cases of brain damage. Also, before PDFs and the internet, it was likely pretty hard for textbook writers to get their hands on the actual case notes to fact check what they'd heard.

But another big reason that myths grew about Gage is the same reason he's a pretty important figure in the history of psychology. Almost immediately, he became like a pawn in fights over how the brain works. Today, we take for granted the idea that parts of the brain are specialized for certain purposes, but at the time, no one was certain of that. And others had a more holistic view, basically that all of it was equally important for pretty much everything. In fact, at the time, the biggest proponents of specialization were phrenologists, adherents of the racist pseudoscience which proposed that personality and intelligence were related to bumps in the skull.

So some psychologists may have emphasized Gage's recovery specifically to attack phrenology. And being able to recover did seem to argue against specialization. After all, if the brain was specialized, you couldn't lose a lot of brain tissue and still be mostly fine. Meanwhile, according to the phrenologists who, again, were wrong, the rod hit him in the parts of the brain responsible for benevolence and veneration. So they likely over-emphasized the changes in his social abilities, leading to the bizarre stories that then snowballed.

Today, Gage's true story fits with our understanding of brain specialization, just not the way that phrenologists thought. What exactly happened to his brain wouldn't be studied in depth until over a century and a half after his accident. Gage died 11 years after the incident and was buried but his skull was later exhumed. And in a study published in 2012 in PLoS ONE, researchers were able to create a 3D model of that skull to fully examine what happened to it.

Based on the placement of the fractures and what's known from modern imaging of brain anatomy, the researchers suggest that the damage was largely to his left frontal lobe, a part of the brain which is associated with decision making and emotional processing. That might explain some of the more subtle deficits he suffered.

They also found that it was likely most of the damage occurred to white brain matter instead of grey matter. Brain tissue that appears white is made of the myelinated axons that connect neurons, while grey matter is made mostly of neuron cell bodies. The research proposed that Gage lost about 11 percent of his white matter, specifically, white matter connecting the orbitofrontal cortex of the frontal lobe to the limbic system, while perhaps only losing four percent of his grey matter. And that could help explain his recovery, because while grey matter doesn't grow back well after injury, it is possible for white matter to regenerate.

This also makes Gage's case look a lot like modern degenerative diseases like frontotemporal dementia. Similar brain regions are affected by the disease, and some of the symptoms associated with personality change can also occur.

And that modern comparison is a good reminder of why it's important to debunk the myths about Phineas Gage. The wild stories about him becoming an unemployable vagrant can end up dehumanizing him. And we don't wanna do that to people who experience accidents or brain damage today. So keeping in mind the full life he lived after his accident can help remind us that everyone deserves to have their story told right, and the human brain is incredibly resilient.

Thanks for watching this episode of SciShow Psych. If you like learning about the human brain, you are in the right place. Check out some of our other episodes to learn more about how our minds work. I really like the one we did on how surprisingly smart babies are, for example, because my baby is definitely surprisingly smart. And don't forget to click on that subscribe button to make sure you never miss an episode.