I first heard of the curious case of Phineas P. Gage in a Psychology I lecture back in the eighties.

25-year-old Gage was foreman of a work gang blasting rock in preparation for the roadbed for the Rutland & Burlington railroad outside the town of Cavendish, Vermont. He was charged with compacting the blasting powder, fuse and sand inserted into holes drilled into bedrock, using an instrument called a tamping iron, a long rod tapered at the end to a fine point like a javelin. At about half-past-four on the afternoon of September 13, 1848, as reported in the Boston Post on September 21, 1848: "the powder exploded, carrying an instrument through his head an inch and a fourth in diameter, and three feet and seven inches in length, which he was using at the time. The iron entered on the side of his face, shattering the upper jaw, and passing back of the left eye, and out at the top of the head." The rod exited his head and landed 25 metres away.

Gage is remembered not only because he survived the trauma, but because his case gave some inkling as to the function of the different parts of the brain – the reason Gage was mentioned in my Psych lecture. Dr. Edward H. Williams, the doctor who attended to the still-conscious Gage reported that he could see his brain pulsating through the hole in his skull and that when he vomited " the effort of vomiting pressed out about half a teacupful of the brain, which fell upon the floor". Although it is not known whether Gage suffered damage to both frontal lobes or just the left one, his case was to provide significant evidence that the frontal lobes give humans the ability to recognise future consequences resulting from current actions, to choose between good and bad actions and suppress unacceptable social responses. Dr. John Martyn Harlow, the doctor who took over care of Gage, wrote in 1868: "The equilibrium or balance, so to speak, between his intellectual faculties and animal propensities, seems to have been destroyed. He is fitful, irreverent, indulging at times in the grossest profanity (which was not previously his custom), manifesting but little deference for his fellows, impatient of restraint or advice when it conflicts with his desires, at times pertinaciously obstinate, yet capricious and vacillating, devising many plans of future operations, which are no sooner arranged than they are abandoned in turn for others appearing more feasible. A child in his intellectual capacity and manifestations, he has the animal passions of a strong man. Previous to his injury, although untrained in the schools, he possessed a well-balanced mind, and was looked upon by those who knew him as a shrewd, smart businessman, very energetic and persistent in executing all his plans of operation. In this regard his mind was radically changed, so decidedly that his friends and acquaintances said he was 'no longer Gage.' "

Gage died in 1860 after a series of seizures.

Photograph: Cased-daguerreotype studio portrait Phineas P. Gage (1823–1860) shown holding the tamping iron which injured him. Until recently it was thought that no photographic record of Gage existed. In 2007, antique photo collectors Jack and Beverly Wilgus posted this scan of a daguerreotype in their collection to Flickr. What they thought was a picture of a whaler holding the harpoon which had impaled him turned out to be a photograph of Gage. On closer inspection an inscription on the rod which Gage is holding reads "... through the head of Mr. Phi". The tamping iron recovered from Gage's grave and kept in the Harvard medical museum reads: "This is the bar that was shot through the head of Mr. Phinehas P. Gage". Some researchers have used the photographic evidence, which shows Gage to be well-dressed and confident, to support a theory that Gage made some emotional and psychological recovery and did not remain the sullen, difficult character that Harlow described.