Describe and evaluate Lateralisation of function
Bredth
The term lateralization refers to the fact that two halves of the human brain have
specialized functions.
Research has found that the left hemisphere is dominant in language and speech,
whereas the right hemisphere excels at visual-motor tasks.
However, we are still able to speak about things that are experienced and
processed in the right hemisphere (e.g., a visual task) and this is because the two
hemispheres are connected by the corpus callosum.
This allows information received from one hemisphere to be sent to the
other hemisphere.
Depth
Roger Sperry investigated the abilities of patients who had undertaken a surgical
procedure called a commissurotomy and this is where surgeons cut through the
bundle of nerve firbres that formed the corpus collosum.
These patients are referred to as split brain patients
Sperry manipulated two tasks – one was a describe what you see task and the other
was a tactile test
In the visual task, an image of a key was presented to the left visual field, the
information would travel to the right hemisphere and as language is dominant in
the left, the patients were not able to say what they saw.
However, if the image was presented to the right visual field, the information
would travel to the left hemisphere, meaning the patients were able to say
what they saw.
In the tactile test, if an object was placed in the patients left hand which would
be processed by the right hemisphere, the patient could not describe what
they felt. Although, they could identify a similar object as they knew how it felt,
but could not say it.
However, if the object was presented in the right hand which is processed by the
left hemisphere the patient could describe what they felt.
EVALUATION
Lateralisation
WEAKNESS
P – Lateralisation of function appears not to stay exactly the same throughout an
individual’s lifetime, but changes with normal ageing. (age is an intervening variable)
E – Lateralized patterns found in younger individuals tend to switch to bilateral patterns in
healthy older adults.
E – For example, it was found that language became more lateralized to the left
hemisphere with increasing age in children and adolescents, but after the age of 25,
lateralization decreased with each decade of life.
L – This shows that lateralization may not in fact be static, but rather changes with age,
lowering the validity of the explanation – lateralized brain function is in fact only a feature
of young adults and not true for everyone (individual differences). Therefore, we must
take a more idiographic approach.
Bredth
The term lateralization refers to the fact that two halves of the human brain have
specialized functions.
Research has found that the left hemisphere is dominant in language and speech,
whereas the right hemisphere excels at visual-motor tasks.
However, we are still able to speak about things that are experienced and
processed in the right hemisphere (e.g., a visual task) and this is because the two
hemispheres are connected by the corpus callosum.
This allows information received from one hemisphere to be sent to the
other hemisphere.
Depth
Roger Sperry investigated the abilities of patients who had undertaken a surgical
procedure called a commissurotomy and this is where surgeons cut through the
bundle of nerve firbres that formed the corpus collosum.
These patients are referred to as split brain patients
Sperry manipulated two tasks – one was a describe what you see task and the other
was a tactile test
In the visual task, an image of a key was presented to the left visual field, the
information would travel to the right hemisphere and as language is dominant in
the left, the patients were not able to say what they saw.
However, if the image was presented to the right visual field, the information
would travel to the left hemisphere, meaning the patients were able to say
what they saw.
In the tactile test, if an object was placed in the patients left hand which would
be processed by the right hemisphere, the patient could not describe what
they felt. Although, they could identify a similar object as they knew how it felt,
but could not say it.
However, if the object was presented in the right hand which is processed by the
left hemisphere the patient could describe what they felt.
EVALUATION
Lateralisation
WEAKNESS
P – Lateralisation of function appears not to stay exactly the same throughout an
individual’s lifetime, but changes with normal ageing. (age is an intervening variable)
E – Lateralized patterns found in younger individuals tend to switch to bilateral patterns in
healthy older adults.
E – For example, it was found that language became more lateralized to the left
hemisphere with increasing age in children and adolescents, but after the age of 25,
lateralization decreased with each decade of life.
L – This shows that lateralization may not in fact be static, but rather changes with age,
lowering the validity of the explanation – lateralized brain function is in fact only a feature
of young adults and not true for everyone (individual differences). Therefore, we must
take a more idiographic approach.
