Explain one study related to localization of function in
the brain.
Introduction
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State what you are doing in the essay
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This essay will attempt to give a detailed account including reasons or causes of localization of the brain
Define Localization of Function (LOF)
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LOF is the theory that certain areas of the brain correspond to certain functions; in that specific areas of the
brain control different functions carried out by the brain.
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It refers to the idea that behavior, emotions and thoughts originate in the brain in specific locations.
Therefore, damage to relevant areas of the brain can cause drastic loss of that function and even more,
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depending on the individual.
Therefore it is said that many functions of the brain are strictly “localized.?
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State/Introduce the parts of the brain The basic set-up of the brain includes:
2 main hemispheres:
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Left – logic, problem solving, maths, and language, controls RHS of body
Right – creativity, emotion, beliefs controls RHS of body
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4 main lobes:
 Occipital – vision
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Parietal – higher senses and language functions
Frontal – reasoning, problem solving, judgement and creativity
Temporal – perception, hearing (sound recognition), memory and meaning.
Other important areas of the brain include:
Broca’s Area – inability to produce language, but could understand/comprehend.
Wernicke’s Area – inability to understand language, but could communicate/speak
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Introduce research into LOF
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Research from the 19th and 20th centuries has guided us towards a much better understanding of how we
should carry out such research into the brain, but more specially, how functions of the brain are localized.
Body
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Introduce research into LOF (be more specific)
Scientific research into brain function was, until the 20th century, largely limited to case studies of individuals
who were known to have suffered some kind of brain damage or head injury.
This type of research, not being of an experimental nature, could never clearly establish a cause and effect
relationship between the behaviour of the person before death and location of the brain damage.
Study 1: Phineas Gage (1848)
Aim:
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To investigate the localisation of function in Phineas Gage’s case of how his brain damage resulted in a change of
behaviour.
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Specifically, Harlow wanted to investigate how the particular brain damage altered his behaviour.
Method:
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Phineas Gage, a 25-year-old railroad worker in the 19th century who survived the passing of an iron rod through
his head/skull.
o It entered below his left cheek and exited through the top of his skull on the frontal lobe.
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J.M Harlow nursed Gage to recovery observing his behaviour.
Results:
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Harlow observed and studied Gage, having undergone dramatic changes in personality after the injury, which he
didn?t show beforehand.
o Harlow described him as having little restraint, using extremely rude language, and making grand plans for the
future, which would be instantly replaced with others.
Conclusion:
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From Harlow’s study of Phineas Gage, it can be concluded that Gage’s frontal lobes were indeed damaged in the
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left pre-frontal region, which accounted for his disinhibited behaviour.
Harlow’s study exemplifies how different parts of the brain, in this case, the frontal lobe which controls personality,
relating back to the theory of localization of function, which is that specific regions of the brain are responsible for
different functions.
Evaluation:
Strengths:
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A large sample was used with many controls to rule out alternative effects on brain activity.
Previous findings on brain structures involved in violence are supported and new findings revealed.
Limitations:
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The PET scan method can lack precision, as the findings apply only to a subgroup of violent offenders (not to other
types of violence or crime) and caution in the interpretation of the findings is needed, which need to be replicated.
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The findings do not mean violence is caused by biology alone (other social, psychological and situational factors
are involved).
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It does not demonstrate that the murderers are not responsible for their actions.
It does not mean PET scans can diagnose murderers and do not say whether the brain abnormalities are a cause or
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effect of behavior.
No control over the level of violence used in the murder.
Brain scans can be difficult to interpret.
Ethical implications of socially sensitive research.
Conclusion:
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Raine et al's study on NGRI's illustrated localization of function
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Differences were found in the amygdala and corpus callosum of the NGRI's, amongst various structures,
suggesting differences in their experience of emotion of fear and their inability to contemplate consequences of
their actions
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The use of this new technology enables psychologists to see the functioning structures of the brain whilst
performing specific tasks
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This hence allowed Raine to compare the functions of various brain regions, effectively showing changes in these
areas in NGRI subjects and how they subsequently affect subjects' functioning
Study 5: Sperry (1968)
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Introduce study and link to question:
o An influential study, which helped neuroscientists to understand the way brain functions appear to be not only
localized in specific regions, but also lateralized – that is, the left and right hemispheres seem to be more or less
responsible for certain activities was from the work of Roger Sperry (1968).
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*Be careful with this study, and be explicit about the localization of function that Sperry demonstrated.
Note that laterization of function is not the same as localization of function, so answers using Sperry need to
focus on the function of the corpus callosum, not on differences between left and right hemispheres of the
brain.
Aim:
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To investigate both the localisation and laterization of brain functions.
To test the effects of a severed corpus callosum, and therefore prove that the two hemispheres have separate
functions.
Method:
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He selected 11 patients who had severed corpus callosums, where the corpus callosums were severed in epilepsy
sufferers to prevent seizures crossing from one side of the brain to another.
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The patients were asked to perform hemisphere-related tasks.
The tasks included being shown an image on the left or right hand side of their body, where they were asked to
identify it or asked to drawn pictures with their left or right hands based off an example.
Results:
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Sperry found that the patients could redraw pictures with their left hands, but not with their right.
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This could be due to the fact that the left hand side of the body is controlled by the right hemisphere, which is
also the creative hemisphere.
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Sperry also found that when a picture was shown on the left they could not identify it, but could recognise it out
of a variety of objects (right hemisphere knows object function but not name).
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Inversely, when the object was shown on the right the patients were able to identify what it was.
Evaluation:
Strengths:
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Although, Sperry only had 11 participants, he found significant information into the insight of localization of brain
function as well as laterization, which is the theory that the two hemispheres have separate functions.
Limitations:
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His study was seen to have low ecological validity, as it only had 11 participants/patients.
Furthermore, more research needs to be undertaken regarding people who do not have a severed corpus
callosum, so that it can be distinguished as to whether Sperry’s results can be applied to the general population.
Conclusion:
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Through this study, Sperry found significant information into the insight of localization of brain function as well as
laterization, which is the theory that the two hemispheres have separate functions.
o Laterization of function include the assertion that the right half of the brain is dominant for visuo-spatial ability
(demonstrated in tasks like reading maps or recognizing faces), as well as musical abilities and understanding
intonation in speech.
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The left half of the brain seems to be more positive than the right and is dominant for language and logical or
mathematical abilities.
His research allowed other research to form and take place to gain more insight into how the different parts of the
brain functions.
Conclusion
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What has been discovered through this essay? Make a link to the learning outcome
The theory of localization of function within the brain is clearly established, and has relevant studies to support
it as seen by Harlow’s work on Phineas Gage and other studies.
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It is generally accepted that there are two hemispheres within the brain which each control separate functions.
Similarly, the four lobes of the brain and other areas of the brain are understood to have separate functions,
primarily to do with the senses.
What did Harlow’s study (or other study) signify?
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Harlow’s study (1848) helped to demonstrate localization of brain function, in how different parts of the brain
are responsible for specific human activities and behaviour.
State explicitly what area of the brain affected what behaviour in Phineas Gage’s condition.
 In Gage’s case, Harlow discovered that the frontal lobes were responsible a change in personality and
emotional vibe, which Gage showed a significant change in behaviour of.
However, more research needs to be undertaken in this area to ensure better understanding of the human
brain.
Hints & Tips
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Short-answer questions may require you to write an explanation of a study connected with localization of function.
In order to write a good response, you need to describe the study and clearly indicate how it shows that brain
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functions are localized.
Specifically: detailing what part of the brain was affected, how the researcher found out, and what the effect on
behaviour, cognition or emotion was.
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