AQA A Level Psychology Paper 2
4.2: Psychology in Context
Topic: Biopsychology
All 16 marker topic essays
1) Discuss the extent to which brain functions are localised (16)
Localisation is the theory that different brain areas are responsible for different
behaviour processes. Our brain is divided into two parts, the left and the right
hemisphere, and some of our physical and psychological functions are
controlled by particular hemispheres, this is known as lateralisation. Activity on
the left hand side of the body is controlled by the right hemisphere and activity
on the right hand side of the body is controlled by the left hemisphere. The
cortex of both hemispheres is subdivided into 4 lobes.
Firstly, the motor area, which is located in the frontal lobe, is responsible for
voluntary movement in the opposite side of the body. The somatosensory area
is located in the front of both parietal lobes and this is where sensory
information from the skin is represented. The visual area is located in the
occipital lobe and is responsible for processing visual information. Finally, the
auditory area is located in the temporal lobe and analyses speech based
information. Damage to this area may produce partial hearing loss.
Other important areas of the brain are the language centres which are located
in the left hemisphere. Broca’s area, located in the left frontal lobe, is
responsible for speech production, and damage to this area causes Broca’s
Aphasia which slows speech and affects fluency. Wernicke’s area, found in the
temporal lobe, is responsible for language comprehension, and so damage to
this area leads to Wernicke’s Aphasia, where an individual is able to speak but
not understand language, and will produce nonsense words as part of their
speech.
A strength of localisation is research support from brain scans. For example,
Peterson et al used brain scans to demonstrate how Wernicke’s area was
active during a listening task and Broca’s area was active during a reading
task. This evidence suggests that these areas are distinct and separate as
they are active during different tasks, and so many neurological functions are
,localised, especially in relation to memory and language. Moreover, brain
scans enable us to see what brain activity is active in what specific parts of the
brain. Thus, this increases the external validity of localisation of the brain, as
objective, scientific evidence supports it.
Another strength of localisation is research support from case studies. For
example, Phineas Gage suffered from an accident, which resulted in a metal
pole exiting his skull taking most of his brain and the left frontal lobe.
Therefore this supports localisation of the brain as the damage resulted in a
change of personality as the area of the brain responsible for behaviour, the
frontal lobe, was damaged. However, this study lacks ecological validity as
case studies are unique one-off cases and everyone’s brain may differ, thus
we’re unable to generalise findings from this study to the wider population.
This also highlights the issue of using a nomothetic approach in psychology,
as we cannot always generate laws for human behaviour based on individual
experiences.
A limitation of localisation of function is research investigating it may display a
form of beta bias. For example, Herasty found that women have proportionally
larger Broca’s and Wernicke’s areas than men, which can perhaps explain the
greater ease of language use amongst women. This suggests that we’re
unable to generalise research examining localisation to males and females
equally, as the different brain structures suggest that different considerations
are required when considering both sexes.
, 2) Plasticity and functional recovery (16)
Brain plasticity refers to the brain’s ability to change and adapt because of
experience, this generally involves the growth of new connections. During
infancy, the brain experiences a rapid growth in the number of synaptic
connections it has, Gopnick et al found that this peaks at about 15,000 per
neuron at 2-3 years. This is about twice as many as there are in the adult
brain, because as we age, rarely used connections are deleted, and
frequently-used connections are strengthened, this is synaptic pruning.
Research has demonstrated that the brain continues to create new neural
pathways and alter existing ones in response to changing experiences. Kuhn
et al found a significant increase in grey matter in various regions of the brain
after participants played video games for 30 minutes over a two-month period.
Similarly, Davidson et al demonstrated the permanent change in the brain
generated by prolonged meditation. Buddhist monks who meditated frequently
had a much greater activation of gamma waves than students who had no
experience of meditation did.
One strength of plasticity is research support from Maguire et al. They studied
the brains of London taxi drivers and found significantly more volume of grey
matter in the posterior hippocampus than in a matched control group. As part
of their training, London taxi drivers must take a test called ‘The Knowledge’
which assesses their recall of the city streets and possible routes, and
Maguire et al found that this learning experience alters the structures of the
drivers’ brains, as well as the fact that the longer the taxi drivers had been in
their job, the more pronounced the structural difference was, showing a
positive correlation. Therefore, this suggests that the brain can permanently
change in response to frequent exposure to a particular task, providing
support for plasticity. However, Maguire’s research is said to be biologically
reductionist as it only examined a single biological factor - the size of the
hippocampus - in relation to spatial memory. Therefore, this fails to take into
account all of the other biological and cognitive processes involved in spatial
navigation which may limit our understanding of plasticity.
One limitation of plasticity is it may have negative behavioural consequences.
Evidence has shown that the brain’s adaptation to prolonged drug use leads
to poorer cognitive functioning in later life, as well as an increased risk of
dementia. Also 60-80% of amputees have been known to develop phantom
limb syndrome: the continued experience of sensations in the missing limb as
