topic 4 - Damasio et al (1994) - Phineas Gage Flashcards
what was the background of the study?
in 1848, Phineas Gage was working on a railway when there was an explosion. A Iron rod was fired in the air and as a result and went through this head. Although there was some serious damage to his face and his frontal lobe, he survived. He recovered from his physical injuries but his personality changed. He went from being a calm and responsible person to rude and irresponsible.
Psychologists tried to understand how his personality went through a sudden change and what it teaches about the role of the frontal lobe. When Gage died 12 years later from epilepsy Harlow, his doctor requested that he could study his skull.
Later, Damasio and her colleagues were able to use the skull to further understand the damage caused to Gages brain as it was kept in the University of Harvards Library and use modern methods of investigation.
what was the aims of the study?
The aim was Damasio et al wanted to discover is other areas of the brain apart from the frontal lobe had also been damaged.
They did this by creating a 3d computer representation of the skull including the holes which were made by the iron rod. They wanted to identify which parts of the brain were likely to be badly damaged in the accident.
what was the procedure?
first, Damasio et al began by taking pictures and measurements of Gages skull. From that information they built a virtual 3d replica of the skull which matched the measurements.
second, they measured the iron rod, which was 3cm in diameter and 109cm long. They compared this to the parts of the skull that were damaged in order to work out the likely path that the iron bar would have taken when it blew through his head. They matched up possible entry and exit points for the iron rod in their model.
finally, they tested 20 possibly entry points and 16 different exit points. They found 5 likely paths and used a virtual replica to map out areas which would have been damaged in each case.
what were the results?
Damasio et al found that there was likely damage in both hemispheres of the frontal lobe in Gage’s brain. The confidently assumed that the accident only affected Gage’s frontal lobe and no other parts of the brain. The iron rod passed through the left eye socket and upwards through the head. This meant that there was likely to have been more damage to the underlying white matter in the left hemisphere than the right frontal lobe. Damaging the white matter are meant that Gage was unable to pass neural messages in this part of his brain making it useless. The damage in the underside (ventromedial region), while the top edges (dorsolateral regions) of the frontal lobe were less affected.
what was the conclusion of the study?
They concluded that the ventromedial area of the frontal lobes seem to be important for making sensible decisions and controlling our impulses around people. It also seems to be important for the control of emotions as Gage found this very difficult after his accident.
The evidence supports other findings that had been gathered from case studies of people with brain damage in similar areas. Damasio et al had evidence of 12 other patients with similar frontal lobe damage who all showed the same problems with impulse and emotional control. This knowledge can be used to predict behaviour of someone who suffers brain damage in these areas.
what are the strengths of the study?
one strength is that the researchers were able to use modern day technology to investigate the data from 1848, meaning the results can be given more scientific status. The use of the computer model in the study meant that evidence could actually be seen not just inferred from the information given after the accident. This increases the scientific understanding of the Gage case.
Another strength is we can now we can make prediction about what changes of behaviour might develop if a person damages their frontal lobe. If the patient damaged their frontal lobe in a similar area to gage, then we can predict that they may become more impulsive and less able to control their behaviour. This could help the family understand that might happen and why it is happening and it could also be useful for helping to treat the person after brain damage.
what are the weaknesses of the study?
one weakness is that even though they used an exact replica of Gage’s skull, the information about how the accident happened is based on reports originally gathered over 150 years ago. This means the information may not be very accurate or a simply a guess from the reports they could find, so it may not be very reliable.
another weakness is there is a problem with generalising the information about the study to other people because the brain damage is unique to Gage. It is very unlikely that someone else will suffer the exact same damage., so the information may not be very useful for helping us understand what might happen to another person with frontal lobe damage.
