Chapter 4 Physiological psychology
1
Maguire et al.
Section A questions
Section B questions
1 (a) Explain why Maguire et al. used taxi drivers in their study. [2]
(b) Identify two criteria used to select the taxi-drivers as participants in
this study. [2]
2 (a) Describe one finding from this study. [2]
(b) Suggest how the findings from this study might be used. [2]
(b) Outline the aim of this study. [2]
(c) Explain why this study can be considered a
snapshot study. [4]
3 Outline two major ideas of the physiological approach to psychology that
are in the study by Maguire et al. [4]
4 (a) Outline one control that was used in the study on brain scanning by
Maguire et al. [2]
(b) Explain why it was important to use this control. [2]
(d) With reference to this study, suggest one
strength and one weakness of conducting
snapshot studies. [6]
(e) Describe the procedure followed this study. [8]
(f)
5 In the study by Maguire et al.:
(a) Describe one method used to analyse the brain scans. [2]
(b) Describe one result obtained using this method. [2]
M ODEL ANS WERS TO THE E X A M-S TY LE QUE S TI ONS I N TH E B O O K
(a) Answer the following question with
reference to the Maguire et al. study:
Suggest how the procedure followed in this
study could be improved. [8]
(g) Outline the implications of the procedural
changes you have suggested for this study. [8]
6 Maguire et al. found a positive correlation in their study of taxi drivers’ brains.
(a) Explain the term ‘positive correlation’, using examples from this
study. [2]
(b) State one conclusion that can be drawn from this result. [2]
Section C questions
7 In the study by Maguire et al., the taxi drivers and control participants
were matched.
(a) Explain how the participants were matched. [2]
(b) Explain why it was important to match the two groups of participants. [2]
(b) Describe how the physiological approach
could explain memory. [4]
8 In the study by Maguire et al.
(a) Identify one independent variable (IV) and one dependent variable
(DV). [2]
(b) Describe the effect of one of the IVs on the DV. [2]
(a) Outline one assumption of the physiological
approach. [2]
(c) Describe one similarity and one difference
between the Maguire et al. study and
any other core studies that take the
physiological approach. [6]
(d) Discuss strengths and weaknesses of the
physiological approach using examples from
any core studies that take this approach. [12]
9 In the study by Maguire et al. describe the participants involved in the
study. [4]
10 In the study by Maguire et al.
(a) Identify two techniques used to analyse the size of the participants’
hippocampus. [2]
(b) Outline one difference that was found between the taxi drivers and
control participants. [2]
Section A questions
1 (a) They used taxi drivers because of their extensive training
required in order to acquire The Knowledge to become a
licensed London cab driver. The training is usually very
intense over a period of two years and then in their jobs
they need to use their navigational skills at all times. It
is unlikely that any other identifiable group would have
undergone such intense navigational experience like this.
(b) One criterion was age: they had to be between 32 and
62. Another criterion was mental health: they had to have
been healthy previously.
2 (a) One finding from this study was that the posterior
hippocampus was larger for the taxi drivers than for the
controls.
(b) They can be used to help understand and help people
who have suffered from brain damage. It suggests that it
is possible for the brain to alter and change in response
to experience – which means that it is possible for stroke
victims to improve given appropriate stimulation.
3 One major idea of the biological approach is that the brain
reflects our experience and our behaviour. This is shown
by this study as the hippocampal volume seems to reflect
the experience of navigation in the two groups (taxi drivers
versus controls) and the right posterior hippocampal volume
correlated positively with number of years of driving. Another
idea of the biological approach is that we are a complex
biological machine, with parts which are highly specialised
in function. This is shown in this study, as it does not just
look at ‘the brain’, or even at how one structure of the brain
has a particular function. In fact, this shows that even just
© Psychology Press 2013
one structure – the hippocampus – does not have a single,
uniform function or purpose. The right and left body, anterior
and posterior all showed differing results, suggesting that the
different parts of the hippocampus have a different purpose.
This supports the biological idea that we are highly complex
machines.
4 (a) One control was that the control group were matched for
age. Overall the profile of the control group had the same
mean age (44) and the same range (age 32–62).
(b) It was important to have this control so that any
differences between the taxi drivers’ hippocampal volume
and that of the controls could not be explained by age
differences and only by taxi driving.
5 (a) One common technique of brain scanning is MRI –
magnetic resonance imaging. This technique essentially
takes images of the brain and brain structures by making
the atoms in the brain ‘spin’ by exposing the person to
a massive magnetic force. Also, the machine gives out
radio waves. A detector in the MRI machine reads the
radio signals from the cells in the brain as the magnet is
switched on and off and this is converted into images of
the brain.
(b) There were two brain regions with significantly increased
grey matter; the right and left hippocampi.
6 (a) A positive correlation is when, usually in the same
people, two measurements are taken, and that as one
increases, so does the other. Maguire et al., found that
as the number of years of taxi driving increased, so did
the posterior hippocampal volume.
Chapter 4 Physiological psychology
7
M ODEL ANS WERS TO THE E X A M-S TY LE QUE S TI ONS I N TH E B O O K
8
9
10
(b) Maguire et al. suggest that it shows that the posterior
hippocampus increases in size because of the increase
in mental maps and navigation, and therefore this study
suggests that our brains can change and alter due to
experience.
(a) This means that each participant in the experimental
groups had a counterpart in the control group which was
identical in terms of age and gender.
(b) They were age-matched because it is likely that brain
volume and density changes with age. Therefore,
the researchers wanted to control for this so that
any differences between the taxi drivers and the
controls could be said to be related to the navigational
experience, and not due to being younger or older.
(a) The independent variable was whether the participant
was a London taxi driver or not. The dependent variable
was the size of the hippocampi and the distribution of the
grey matter.
(b) Being a London taxi driver alters the distribution of
the grey matter between the anterior and posterior
hippocampus.
16 London taxi drivers with a mean age of 44, who were all
licensed for more than 1.5 years, male and right-handed.
(a) VBM stands for voxel-based morphometry which identifies
differences in the density of grey matter in different
parts of the brain; grey matter is linked with higher order
thinking. Pixel counting measures hippocampal volume by
counting pixels in slices of the brain.
(b) One difference between taxi drivers and controls was that
the right and left hippocampi had significantly increased
grey matter.
Section B questions
(a) The study aim is to find out whether changes could be
detected in the brains of humans who have extreme
experiences of spatial navigation; it investigated whether
brain structures could alter in response to environmental
stimuli.
(b) This is a snapshot study allowing the researchers to
investigate different people at the same time. The study only
views the brains of the participants at one particular time
rather than viewing them over a long period to assess the
changes taking place, which would have been a longitudinal
study.
(c) One strength of snapshot studies is that the data can be
collected within a relatively short space of time and without
the risk of attrition (loss of participants over time). In the
case of Maguire et al., all the brain scans could be collected
and analysed at once without having to wait for changes to
take place in the brains of the taxi drivers.
One weakness of snapshot studies is that you cannot know
that differences between brains is due to the independent
variable; they may just be due to natural individual
differences. In this case, the changes in the hippocampi
could have been due to the taxi driving experience or may
have been natural to the individual participants.
(d) The experimental group and the control group had structural
MRI scans which were then analysed using voxel-based
morphometry (VBM) and pixel counting. In the VBM,
differences in density of grey matter in different parts of
the brain were analysed. In the pixel-counting procedure,
hippocampal volume was calculated using a counting method
of single points on the MRI scan images. 26 ‘slices’ of the
brain were analysed by experienced analysts who did not
know whether the scan they were looking at was a taxi driver
or not. Total hippocampal volume was calculated by adding
up the pixels from each slice and multiplying this by the
distance between the adjacent slices. A correction was then
made to account for the fact that some people would have
larger brains than others.
(e) One change in this study could be to have women
participants. These would be in both the taxi driver sample
and the control sample. As in the original study, they would
© Psychology Press 2013
2
be matched for age.
Another change to this study would be to recruit a sample of
left-handed taxi drivers and controls. In the same way, they
would be matched for age, etc.
(f) It is difficult to say whether the first change would alter the
results. Often, people claim (and some research has backed
this up) that women are less good at navigation and mental
maps than men and it is possible that conducting MRIs in
this way may discover that the female taxi drivers do not
have such a markedly different posterior hippocampal volume
as the male taxi drivers; and that this might bring down the
overall significance of the results. However, it might also be
possible that female brains have slightly different areas of
specialism and it might be that a different part of the brain
shows changes according to years of taxi driving. Certainly,
this would be an interesting change to the study and would
tell us about female brains and navigation, which the original
study does not.
It would be interesting to see what effect left-handed
participants had on the results. Instead of finding that it
was the right anterior hippocampus which was larger in
the controls than in the taxi drivers, the picture might be
reversed – that it was the left and so on.
Section C questions
(a) One assumption of the biological approach in psychology
is that much of human behaviour is governed and
can be explained by biology, e.g. hormones, genes,
neurotransmitters, brain structure and so on. This means we
probably have less control and free will than we would like to
think.
(b) The physiological approach could explain memory by arguing
that particular structures in the brain are related to specific
cognitive functions. In Maguire’s study, evidence suggests
that the hippocampus plays a special role in memory related
to navigational tasks. The physiological approach would also
suggest that a great deal of use of a particular cognitive
function such as memory could cause structural changes in
the brain.
(c) One similarity with Dement and Kleitman is that both studies
monitor the brain. Maguire et al. use an MRI scan, while
Dement and Kleitman uses an EEG. Both studies use these
techniques because both are interested in the relationship
of the brain with psychological phenomena – Dement and
Kleitman are interested in linking the biological event or REM
with the psychological event of dreaming; Maguire et al. are
interested in linking the biological structure of the brain (size
of hippocampus) with the psychological activity of navigation.
One difference between the two studies is that Dement and
Kleitman’s study is monitoring ongoing, ‘live’ changes in
brain activity. The EEG shows differing levels of activity in the
brain as it is really happening, second by second, (akin to
‘live TV’). By contrast, the MRI only shows a one-off image
of the brain, fixed at a particular point in time (akin to a
photograph).
(d) One strength of the biological approach is that it is scientific.
It probably represents the most scientific end of psychology.
This means that it is objective, usually empirically based
and widely respected. For example, in Maguire et al. the
procedures use advanced technological processes and
equipment and the procedures were highly controlled, with
the same VBM, pixel-counting techniques and single-blind
technique, so observers did not know whose scans they
were analysing. Because all these aspects of the procedure
increase the validity and objectivity of the research, it is
widely accepted and respected.
Another strength of the biological approach is that it generally
produces useful contributions to psychology – both in terms
of applications and in terms of usefulness for helping further
research in the area. For example, Kleitman’s work on the
physiological/biological aspects of sleep and dreaming
means that he is often described as ‘the father of modern
sleep research’ – linking REM and dreaming has meant that
the research provided a tool (both for other research and
Chapter 4 Physiological psychology
M ODEL ANS WERS TO THE E X A M-S TY LE QUE S TI ONS I N TH E B O O K
for diagnosing people with sleep disorders) for investigating
sleep. This really has changed the way that we think
about sleep, work with sleep disorders, and how sleep is
researched.
One weakness of the biological approach is that it can
be reductionist – only looking at simple explanations. For
example, in Dement and Kleitman, they are not interested
in the psychological motivations for particular dreams, why
people dream particular things and what they might mean.
So whereas Freud would be interested in interpreting the
content of the dream in terms of fears and wishes, the
biological approach completely ignores this. Therefore, it
could be said that it is reductionist as it only looks at the
simple explanations and ignores more complex psychological
© Psychology Press 2013
3
explanations. Dreaming is probably a fusion of physiological
activity and ‘subconscious’ activity.
Another weakness of the physiological approach is that it
overlooks nurture and over-emphasises nature. For example,
the implication of Dement and Kleitman’s study is that
dreaming is hard-wired into humans as a result of the
genetically determined physiological activity of REM and sleep
stages. On the other hand, Maguire et al. avoid this by using
the physiological approach to investigate how experience
(nurture) can actually cause physical changes in the brain,
thus showing that weaknesses of the approach as a whole
is not necessarily true of all research within that approach if
new and interesting directions are taken by researchers.
Chapter 4 Physiological psychology
4
Dement and Kleitman
Section A questions
Section B questions
1 Dement and Kleitman’s study on sleep linked REM activity to dreaming.
Describe two pieces of evidence that supported this link. [4]
Answer the following questions with reference to
the Dement and Kleitman study:
2 In the study of sleep by Dement and Kleitman there was some evidence
that dreams also occurred in NREM sleep.
(a) Explain how they collected this evidence. [2]
(b) How did they explain the dreams being reported in NREM sleep? [2]
(a) Briefly outline the research method used in
this study. [2]
3 Dement and Kleitman used an electroencephalogram (EEG) to record
sleep activity.
(a) Explain what the EEG shows. [2]
(b) Describe one limitation of using an EEG to investigate dreaming. [2]
(c) With reference to this study, suggest one
strength and one weakness of quantitative
data. [6]
(d) Describe the procedures of this study. [8]
4 (a) Identify two of the controls used by Dement and Kleitman in their
study of sleep and dreaming. [2]
(b) Outline why controls are used in psychological research. [2]
M ODEL ANS WERS TO THE E X A M-S TY LE QUE S TI ONS I N TH E B O O K
(b) Describe two examples of quantitative data
recorded in this study. [4]
(e) Suggest how this study could be improved. [8]
(f)
5 In the study of sleep by Dement and Kleitman, participants were told to
abstain from two substances on the day of the experiment.
(a) Identify these two substances. [2]
(b) Outline one problem with this instruction. [2]
Outline the implications of the improvements
you have suggested for this study. [8]
Section C questions
(a) Outline one assumption of the physiological
approach. [2]
6 (a) Identify one of the hypotheses of the Dement and Kleitman’s study
on sleep and dreaming. [2]
(b) Outline the results of the study in relation to this aim. [2]
(b) Describe how the physiological approach
could explain dreaming. [4]
7 Outline two ways that the study by Dement and Kleitman can be said to
be low in ecological validity. [4]
8 With reference to the study by Dement and Kleitman,
(a) Outline one piece of evidence that shows that REM sleep is linked to
dreaming. [2]
(b) Outline one piece of evidence challenges this relationship. [2]
9 Dement and Kleitman investigated aspects of dreaming.
(a) Explain one method they used to measure the duration of a person’s
dream. [2]
(b) Explain how the reliability of this method could be determined. [2]
(c) Describe one similarity and one difference
between the Dement and Kleitman study
and any other core studies that take the
physiological approach. [6]
(d) Discuss strengths and weaknesses of the
physiological approach using examples from
any core studies that take this approach. [12]
10 In the study by Dement and Kleitman, describe the methods that were
used to control extraneous variables. [4]
Section A questions
(a) One piece of evidence was that people were more likely
to recall a dream during REM than they were in NREM.
Another piece of evidence is that the movements of
the eyes in REM matched the content of the dreams.
For example, someone who was observed to have
horizontal eye movements recounted a dream which
involved watching two people throwing tomatoes at each
other. Participants were woken up, either in REM or
NREM (although they didn’t know which) and were asked
‘Were you dreaming – yes or no?’ In general, people
were more likely to report that they had been dreaming
in REM. However, sometimes participants recalled
dreaming in NREM.
(b) The majority of NREM dreams occurred within
eight minutes of an REM episode (and often were
vaguer memories) and so Dement and Kleitman thought
that these NREM dreams were fragments or echoes or
memories of REM dreams.
3 (a) The EEG shows brain waves. This is because it measures
and records electical activity in the brain.
(b) One limitation of using the EEG is it does not give
very precise readings – it only gives a very general
measurement of brain activity.
4 (a) One control was that the questions asked were always
the same and in exactly the same order. Another control
was that the participants were all asked to refrain from
consuming alcohol or caffeine.
(b) Controls are needed in psychological research to ensure
that the only thing that affects the DV is the changes
© Psychology Press 2013
5
6
7
8
in the IV. This helps to establish cause and effect
relationships. If extraneous variables were not controlled,
then it would not be possible to be sure that the DV was
caused by the IV.
(a) Alcohol and caffeine.
(b) Participants might always drink, e.g. a beer or glass of
wine in the evening, and therefore if they had to refrain it
would be unnatural for them and then it might alter their
sleep pattern.
(a) One hypothesis was that there would be a match
between the duration of REM and the estimated duration
of the dream.
(b) Participants were woken either five or 15 minutes into
REM and asked ‘Were you dreaming for five or 15
minutes?’ Overall, participants were more likely to give
an estimation which matched the duration of REM than
not (i.e. say five minutes dreaming when they had been in
REM for five minutes).
It can be said to be low in ecological validity because it took
place in an artificial environment that was very different from
their home, and this was made worse by the attaching of
the electrical equipment. This may have altered their sleep
experience and made it very different from how it usually
was. The fact that the participants were woken so often
during the night may well have resulted in a different pattern
of sleep stages from usual, for example altering the number
or length of REM periods.
(a) That significantly more dreams were reported when
woken from REM sleep than NREM sleep supports the
link between REM and dreaming.
Chapter 4 Physiological psychology
(b) One piece of evidence that challenges this link is that
sometimes participants remembered dreams when woken
from NREM.
9 (a) By observing the length of time that eye movement
patterns were visible to the observer.
(b) It could be matched to the EEG recording of the length of
REM period.
10 Dement and Kleitman controlled the effects of alcohol and
caffeine by asking participants to abstain from these before
the study. They also controlled for the effects of starting
sleep at an unusual time by asking participants to report to
the lab at their usual bedtime.
M ODEL ANS WERS TO THE E X A M-S TY LE QUE S TI ONS I N TH E B O O K
Section B questions
(a) The research method used was a lab experiment with selfreport techniques. It could be said to be a quasi-experiment
because the participants were already in either REM or NREM
sleep.
(b) Quantitative data was the number of times a participant
said they had been dreaming, and the number of times a
participant said they hadn’t been dreaming. [Also correct are
their time estimation of the dream, and the number of words
they used to describe the dream.]
(c) One strength is that it is easy to analyse numbers, e.g.
drawing a bar chart to compare dreams reported in REM and
NREM sleep, and the number of words taken to describe the
dream could be correlated with the number of minutes in
REM.
One weakness is that in some ways such data are
oversimplified – just having a number for how many dreams
were reported or the length of the dream doesn’t tell you
about important differences between kinds of dreams such
as more coherent ones, or ones that are disturbing or happy.
(d) Participants were asked to come to the lab just before their
usual bedtime, having abstained from coffee or alcohol
on the day of the study. Electrodes were attached around
their eyes to measure electrical activity and therefore eye
movement, and to their scalp to measure brain waves via
EEG. The participants went to sleep in a darkened room. At
various times in the night participants were woken by a bell
by their bed. They were awoken to a random pattern either
during REM or during other sleep stages. They were woken
on average 5.7 times per night. They had to say into the tape
recorder if they had been dreaming or not, and if so how long
they had been dreaming for and what about. The participant
could then go back to sleep.
(e) One change to the study is that it could be conducted
on a larger sample of participants. Instead of just nine
participants, they could widen it to, e.g. 20 or even 50
participants and study each participant for two or three
nights. Another change to the study could be that they
conduct it in the participant’s home instead of in a
laboratory.
(f) In terms of the overall results, they would probably find
that there was still a strong relationship between REM and
dreaming. However, they might uncover more individual
differences in terms of the pattern of the different stages
of the sleep stages, duration of REM, and ability to recall a
dream. However, having a larger (and therefore, likely to be
more representative) sample should mean that the results
can more validly be applied to the general population.
This should mean that the participant should sleep more
naturally as they would be in their own bed and normal
sleeping environment (normal smells, bed linen, background
noise and so on). Overall, this might change the pattern of
sleep and depth of sleep – people might sleep more deeply
if they are more relaxed at home), but it probably would not
affect the overall finding that there is a relationship between
REM and dreaming.
© Psychology Press 2013
5
Section C questions
(a) One assumption of the biological approach in psychology
is that much of human behaviour is governed and
can be explained by biology, e.g. hormones, genes,
neurotransmitters, brain structure and so on. This means
we probably have less control and free will than we would
like to think.
(b) The physiological approach could explain dreaming by
focusing on the different stages of sleep and the brain
wave patterns of each. REM sleep seems to be linked with
dreaming, and REM sleep is governed by physiological
processes associated with electrical activity in the brain.
(c) One similarity is with Maguire et al., where both studies
monitor the brain. Maguire et al. use an MRI scan, while
Dement and Kleitman use an EEG. Both studies use these
techniques because both are interested in the relationship
of the brain with psychological phenomena – Dement and
Kleitman are interested in linking the biological event or REM
with the psychological event of dreaming; Maguire et al. are
interested in linking the biological structure of the brain (size
of hippocampus) with the psychological activity of navigation.
One difference between the two studies is that Dement and
Kleitman’s study is monitoring ongoing, ‘live’ changes in
brain activity. The EEG shows differing levels of activity in the
brain as it is really happening, second by second, (akin to
‘live TV’). By contrast, the MRI scans used in Maguire et al.
just show a one-off image of the brain, fixed at a particular
point in time (akin to a photograph).
(d) One strength of the biological approach is that it is scientific.
It probably represents the most scientific end of psychology.
This means that it is objective, usually empirically based
and widely respected. For example, in Maguire et al., the
procedures use advanced technological processes and
equipment and the procedures were highly controlled –
the same VBM and pixel-counting techniques, single-blind
technique so observers did not know whose scans they
were analysing and so on. Because all these aspects of
the procedure increase the validity and objectivity of the
research, it is widely accepted and respected.
Another strength of the biological approach is that it generally
produces useful contributions to psychology – both in terms
of applications and in terms of usefulness for helping further
research in the area. For example, Kleitman’s work on the
physiological/biological aspects of sleep and dreaming
means that he is often described as ‘the father of modern
sleep research’ – linking REM and dreaming has meant that
the research provided a tool (both for other research and for
diagnosing people with sleep disorders) for investigating sleep.
This really has changed the way that we think about sleep,
work with sleep disorders, and how sleep is researched.
One weakness of the biological approach is that it can
be reductionist – only looking at simple explanations. For
example, Dement and Kleitman are not interested in the
psychological motivations for particular dreams, why people
dream particular things and what they might mean. So,
whereas Freud was interested in interpreting the content
of the dream in terms of fears and wishes, the biological
approach completely ignores this. Therefore, it could be
said that it is reductionist as it only looks at the simple
explanations and ignores more complex psychological
explanations. Dreaming is probably a fusion of physiological
activity and ‘subconscious’ activity.
Another weakness of the physiological approach is that it
overlooks nurture and over-emphasises nature. For example,
the implication of Dement and Kleitman’s study is that
dreaming is hard-wired into humans as a result of the
genetically determined physiological activity of REM and sleep
stages. On the other hand, Maguire et al. avoids this by using
the physiological approach to investigate how experience
(nurture) can actually cause physical changes in the brain,
thus showing that weaknesses of the approach as a whole is
not necessarily true of all research within that approach if new
and interesting directions are taken by researchers.
Chapter 4 Physiological psychology
6
Sperry
Section A questions
Section B questions
1 Sperry studied the abilities of split-brain patients.
(a) Describe one difference between the ability of split-brain patients and
‘normal’ people to identify objects by touch alone. [2]
(b) Give one explanation for this difference. [2]
2 (a) From the study by Sperry, explain why the split-brain operation was
carried out on the patients in the study. [2]
(b) Outline the major function of the corpus callosum. [2]
3 The results of Sperry’s study of split-brain patients suggest that we
effectively have two minds. Outline two pieces of evidence from the study
that show this. [4]
M ODEL ANS WERS TO THE E X A M-S TY LE QUE S TI ONS I N TH E B O O K
4 (a) Describe the technique that Sperry used to present information to
only one side of the brain? [2]
(b) Explain why ‘normal’ people do not have any difficulty with the
technique used to test the split-brain patients. [2]
5 From the paper by Sperry on split-brain patients, outline evidence which
indicates that language is processed in the left hemisphere of the brain. [4]
6 (a) In Sperry’s study, describe one problem with generalising from the
sample. [2]
(b) Explain what is meant by the term ‘left visual field’ as used in the
paper by Sperry. [2]
7 In Sperry’s study of split-brain patients,
(a) Explain what is meant by ‘hemispheric deconnection’. [2]
(b) Outline two psychological effects of hemispheric deconnection. [2]
8 In Sperry’s study, split-brain patients were found to have difficulties on
some tasks.
(a) Describe one conclusion that can be drawn from the observations of
their behaviour. [2]
(b) Explain why patients do not experience these difficulties in everyday
life. [2]
Answer the following question with reference to
the Sperry study:
(a) Briefly outline the previous research or
event which was the stimulus for this study. [2]
(b) Describe the sample used in this study and
suggest one strength of using this sample. [6]
(c) Give two strengths of the self-report method
as used in this study. [6]
(d) Give two weaknesses of the self-report
method as used in this study. [6]
(e) Outline the results of this study. [6]
(f)
Describe and evaluate changes that could be
made to the way this study was conducted. [10]
Section C questions
(a) Outline one assumption of the physiological
approach. [2]
(b) Describe how the physiological approach
could explain the way the brain controls
behaviour. [4]
(c) Describe one similarity and one difference
between the Sperry study and any core
studies that take the physiological approach. [6]
(d) Discuss strengths and weaknesses of the
physiological approach using examples from
any core studies that take this approach. [12]
9 With reference to Sperry’s study, explain why split-brain patients:
(a) Could not describe in speech material presented to their left visual
field. [2]
(b) Could describe an object that they held in their right hand. [2]
10 With reference to Sperry’s study, outline tasks that are controlled by the
right hemisphere. [4]
Section A questions
1 (a) If a split-brain patient touched an object with their left
hand they couldn’t say what it was, though a normal
person could do this.
(b) This is because information from the left hand goes to
the right hemisphere which, in the split-brain patient,
has no connection to the left hemisphere where speech
originates.
2 (a) The operation was carried out as a treatment for
epilepsy. The patients had all experienced serious and
debilitating epilepsy and it was hoped that this operation
would significantly reduce seizures and bring about an
improvement in their ability to lead normal lives.
(b) The corpus callosum serves as a communication
bridge between the left and right hemispheres so that
information can be communicated from one side to the
other.
3 One piece of evidence is from the $/? study. In this study the
person could draw the dollar sign with their left hand but could
not say what they had drawn – the dollar was flashed to the
left visual field which is perceived by the right hemisphere. The
right hemisphere is the silent hemisphere and controls the left
hand. Another example is that Sperry placed two objects, one
in each hand, and then asked participants to find the objects
from in a pile of objects; each hand could find its own object,
but ignored the other hand’s objects. Sperry said, ‘It is like
two separate individuals working over a collection of test items
© Psychology Press 2013
with no cooperation between them’, i.e. like two minds acting
separately in one body.
4 (a) One technique was using touch tests. Sperry would
put an object into one hand only of a split-brain patient
(behind a screen so that the patient could not see it). If
an object is put in the right hand, the feel of this object
is processed by the left hemisphere only; and if an
object is put in the left hand it is processed by the right
hemisphere only.
(b) They do not have a problem because the hemispheres
can communicate. If something is put into a normal
person’s left hand, the information is relayed to the right
hemisphere which can work out from feeling the object
what it might be. The right hemisphere can communicate
with the left hemisphere via the corpus callosum, so that
then the person can say the name of the object out loud.
5 One piece of evidence supporting the idea that language is
produced in the left hemisphere comes from the visual tests.
When participants are shown an image in the left visual
field it is processed by the right hemisphere. Here, when
asked what they could see, split-brain patients generally said
‘nothing’. This is because the ‘talking hemisphere’, the left
hemisphere, had indeed seen nothing. But when an image
is presented to the right visual field (left hemisphere) the
splitbrain patient can readily say what it has seen which
shows that language abilities are in the left hemisphere.
Another piece of evidence comes from the stereognostic
Chapter 4 Physiological psychology
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(touch) tests – an object in the right hand (left hemisphere)
can be identified verbally. But if placed in the left hand
(right hemisphere) the person cannot say what it is but can
recognise it with the same hand.
(a) One problem with the sample is that all of them had
suffered from severe and debilitating epilepsy. Because
epilepsy can be caused by some form of brain damage,
and in itself can cause further neurological problems, it
might be that, even before the commissurotomy, these
patients did not have ‘normal’ brains. Therefore, this
study may not tell us about how a normal person’s brain
works or what would happen if a non-epileptic person had
the same operation.
(b) The left visual field is the area to the left of the central
focus point when looking straight ahead. This visual field
is processed by the right hemisphere.
(a) That the hemispheres are separated by having the corpus
callosum severed.
(b) Information cannot travel from one hemisphere to the
other, and epileptic seizures are limited in frequency and
severity.
(a) People with split brains have two separate ‘minds’ where
one hemisphere does not have access to the information
in the other one.
(b) Because in real life they move their eyes and so the
information enters both visual fields and therefore both
hemispheres.
(a) Because this is processed by the right hemisphere which
does not have language.
(b) Because information from the right hand is processed by
the left hemisphere which does have language.
The right hemisphere deals with information from the left
visual field, as shown by the $ and ? mini-experiment, and
it deals with information from the left hand as shown by the
mini-experiment exploring touch.
Section B questions
(a) The aim of the study was to see whether split-brain patients
(people who had had their corpus callosum cut) showed any
problems or deficit as a result of this operation. Previous
research suggested there were no important behaviour
effects in everyday life in humans but effects had been
observed in animals. Sperry wanted to investigate the
patients under more experimental conditions and work out
how the right and left hemispheres might work. In a way, this
was a perfect opportunity to find out about lateralisation of
brain function.
(b) The sample were all split-brain patients. They had all
had a commissurotomy in order to treat severe epilepsy.
For most of the patients, the operation had reduced the
symptoms of epilepsy. There were only a small number of
participants – approximately six participants. One problem
is that the sample may not show how hemispheres work.
This is because epilepsy can be caused by some form of
brain damage, and in itself can cause further neurological
problems; it might be that, even before the commissurotomy,
these patients did not have ‘normal’ brains. Therefore, this
study may not tell us about how a normal person’s brain
works or what would happen if a non-epileptic person had the
same operation.
(c) One strength of self-report as used in this study was that
it provided a direct way of accessing the participants’
experiences without the experimenter having to make
assumptions or inferences about what was happening. For
example, in the mini-experiment using ‘keycase’ across both
visual fields, asking the participants what they had seen was
the simplest, most direct way of finding out what information
had travelled to the relevant hemisphere.
Another strength is that the experimenters were able to
generate both qualitative and quantitative data by using selfreport. For example, they could ask them what they were
experiencing in a free-format way, such as when they elicited
the information that one participant felt that they were not
© Psychology Press 2013
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getting messages from one hand. This is qualitative data.
Their answers to the tasks themselves enabled a count of
correct responses generating quantitative data.
(d) A weakness of self-report is that participants do not
necessarily tell the truth, so if they had come to an
understanding of what the experimenters expected (because
they understood the nature of their operation and its possible
implications) they may not have given truthful answers such
as when they could not identify an object by touch.
Another weakness is that the self-report technique made it
very obvious to the participant when he/she had failed in a
task such as not being able to say what they had seen. This
may have affected their self-esteem and caused them worry
in a way that a different data collection technique may not
have done.
(e) The results of this study show that, if a projected picture
is shown and responded to in one visual field, it is only
recognised again if it appears in that visual field (VF).
If visual material appears in the right visual field (RVF,
processed by left hemisphere), the participant could describe
it in speech and writing as normal.
If the same visual material is projected to the left visual field
(LVF, processed by the right hemisphere) then the participant
says he did not see anything or says there was just a flash
of light on his left side. (Language centres are in the left
hemisphere.)
If you then ask the same participant to use his left hand
(right hemisphere control) to point to a matching picture or
object in a collection of pictures/objects, he points to the
item he just insisted he couldn’t see.
These results confirm that the right hemisphere cannot
speak or write (called aphasia and agraphia respectively).
(f) One change to this study could be to observe split-brain
patients in their everyday lives to see how their condition
might affect them. They could be watched doing ordinary
tasks in ordinary conditions, e.g. preparing and eating
food, cleaning, interacting with family members, etc. This
would make the study more ecologically valid. It might also
reveal some everyday behaviours which were affected by
having a split brain, which, on a superficial inspection,
seemed quite normal. Another change to this study would
be to use many more patients. This would probably show
overall similar findings and would also help explore the
individual differences between the participants and discover
whether there was any pattern or reasons for why some
participants could show ipsilateral control (right hemisphere
communicating with right hand).
Section C questions
(a) One assumption of the biological approach in psychology
is that much of human behaviour is governed and
can be explained by biology, e.g. hormones, genes,
neurotransmitters, brain structure and so on. This means
we probably have less control and free will than we would
like to think.
(b) The physiological approach could explain how the brain
controls behaviour by demonstrating how the ability to
produce such behaviours as naming objects and identifying
them by touch are governed by the structure of the brain.
This is shown by Sperry’s study where a physical alteration in
the brain causes clear differences between participants.
(c) One similarity between Sperry and Dement and Kleitman
is that both studies included a self-report technique for
collecting data. Sperry’s participants were asked directly
about what they had seen or touched, as well as their
subjective experiences about what was happening to them.
Dement and Kleitman’s participants were asked to report
into the tape recorder the content and length of their
dreams. This means that the researchers in both cases were
accessing directly the participants’ experiences in their own
words.
One difference between Sperry and Maguire et al. is that
while Maguire et al. collected only quantitative data in the
M ODEL ANS WERS TO THE E X A M-S TY LE QUE S TI ONS I N TH E B O O K
Chapter 4 Physiological psychology
form of numerical analyses of brain scans, Sperry collected
both quantitative and qualitative data by looking at test
scores as well as participants’ comments.
(d) One strength of the physiological approach is that it is
scientific. It probably represents the most scientific end
of psychology. This means that it is objective, usually
empirically based and widely respected. For example, in
Maguire et al., the procedures use advanced technological
processes and equipment and the procedures were highly
controlled – same VBM and pixel-counting techniques, singleblind technique so observers did not know whose scans
they were analysing and so on. Because all these aspects
of the procedure increase the validity and objectivity of the
research, it is widely accepted and respected.
Another strength of the physiological approach is that it
generally produces useful contributions to psychology – both
in terms of applications and in terms of usefulness for
helping further research in the area. For example, Sperry’s
study was valuable from a theoretical point of view in order to
understand the brain, its structure and operations, such as
the functions of the hemispheres. This knowledge could be
used about different parts of the brain to better understand
people who have suffered brain damage in, for example, a
car accident. Also, sometimes people need to have brain
tumours removed and surgeons need to know the effects of
removing parts of the brain.
© Psychology Press 2013
One weakness of the physiological approach is that it often
lacks ecological validity due to the nature of the tasks and
the environment where they take place. This means that it
could be argued that they are of limited value in telling us
about people’s mind and behaviour in real, everyday life. For
example, Sperry’s study into split-brain patients revealed a
wealth of detail about how they performed under particular
circumstances that were very unusual. In real life, however,
no such impairments were noted by the patients because
their coping strategies (eye movements) led to their being
able to function perfectly normally.
Another weakness of the physiological approach is that
it overlooks nurture and over-emphasises nature. For
example, the implication of Dement and Kleitman’s study
is that dreaming is hard-wired into humans as a result of
the genetically determined physiological activity of REM
and sleep stages. On the other hand, Maguire et al. avoids
this by using the physiological approach to investigate how
experience (nurture) can actually cause physical changes in
the brain, thus showing that weaknesses of the approach
as a whole is not necessarily true of all research within
that approach if new and interesting directions are taken by
researchers.
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