Maguire

• Outline the background of Maguire's study (4)

  -What is brain plasticity and link to Blakemore and Cooper-The hippocampus and its role for mammals-Whether the human brain structure will change due to the environment-Clarify the role of the hippocampus in the human brainMaguire was inspired by previous research that had been done, specifically by Blakemore and Cooper about functional brain plasticity, however, she wanted to expand on this and research structural brain plasticity.She wanted to investigate the hippocampus, which is a major part of the limbic system in charge of navigation. Previous research had suggested that the hippocampi of some animals grow in size during times when their navigational and special reasoning skills are exercised more often.However, there had been no research illustrating whether human brains would plasticise as a result of environmental changes, therefore,Maguire wanted to investigate this further and the best people to use were London Taxi Driver as they had to learn ‘The Knowledge’ of London and had much navigational experience.
• What was the aim in Maguire's research?

  To investigate the differences in volume in the hippocampus of London taxi drivers and non-taxi drivers.

  She also investigated the possible plasticity in the brain
• What was the sample in Maguire's research? (3)

  Experimental group:-16male taxi drivers-Healthy, all right handed-Mean age44yearsControl:-16 male non taxi drivers-All right handed-Mean age44years
• What was the research method in Maguire's research?

  Quasi experiment
• What was the experimental design in Maguire's research?

  Matched participants design
• What was the IV in Maguire's research?


  Taxi driver or Non-taxi driver
• What was the DV in Maguire's research?

  Volume of the grey matter of the hippocampus
• What was the additional analysis Maguire did and what was the purpose of it?

  In addition Maguire also conducted acorrelational analysisof thesize of the hippocampusof the taxi drivers and thelength of timethat they had been in their profession. This was done to see if hippocampal volume increased withtime.
• What was the procedure in Maguire's research? (3)

  -Taxi drivers brain scanned, whilst brain scans for control (non-taxi drivers) were taken from the MRI scan database.

  -all scans are analysed using VBM which identifies grey matter density and regions of the brain. They compare the taxi drivers and non-taxi drivers.

  -pixel counting compared the volume of the anterior, body and posterior cross sections of the hippocampi taxi drivers and 16 matched non-taxi drivers.
• What was the apparatus used in Maguire's research? (3)

  MRI scanner, scans then analyse using VBM and Pixel counting
• What were the results in Maguire's research?

  VBM analysis and Pixel counting:-No significant differencein overall volume of the hippocampus-Taxi drivers had significantly increased grey matter volume in the right and leftposterior hippocampicompared to controls.-In the controls there was a relatively greater grey matter volume in the right and leftanterior hippocampicompared to taxi drivers.Correlational analysis-As the time spent as a taxi driver increased, the volume of the posterior hippocampi increased. (Positive correlation)-As the time spent as a taxi driver increased, the volume of the anterior hippocampi decreased. (Negative correlation).
• What were the conclusions in Maguire's research?(2)

  -There areregionally specificstructural differences between the hippocampi of licensed London taxi drivers compared to those who do not drive London taxis. This shows evidence of brain plasticity/It can be suggested that the changes in the arrangement of hippocampal grey matter are acquired i.e. due tonurture.-Findings also indicate the possibility of localplasticityin the structure of a normal human brain which allows it to adapt in response to prolonged environmental stimuli.
• What are strengths of the research method in Maguire's study? (3)

  -High controls over extraneous variables– e.g. a matched pairs design was used to match on key characteristics that could effected the hippocampus e.g. age, gender and all right handed (removes individual diffs).

  -Use ofscientific and technical equipment

  -Correlational analysiswas also done to establish a relationship between volume of grey matter in the hippocampus and time as a TD. However,cannot confirm this was the cause.
• What is a weakness of the research method in Maguire's study?

  Quasi experiment, there are always some individual differences that cannot be controlled as the participants cannot be randomly allocated into conditions due to the naturally occurring IV.Impacts internal validity.
• What is a strength of the sample in Maguire's study?

  Although overall a strength to use males to remove gender being an extraneous variable
• What are weaknesses of the sample in Maguire's study? (2)

  -Sample is not typical of the general population and brain plasticity. It may be that not everyone’s brain could or would respond in the same way to the environment demands of doing ‘The Knowledge’ and being a taxi driver in London.

  -Androcentric sample:we do not know the brain plasticity of female taxi drivers.
• What are strengths about the type of data collected in Maguire's study? (4)

  -Use ofhighly technical equipment(MRI scanner) and allows precise measurement of data.

  -Both VBM and Pixel counting provided quantitative data for the volume of grey matter/volume of the hippocampus. This allowed for astatistical analysisof the differences between the two groups and the correlation to be run.

  -Quantitative data enabledhigh reliability and validityof the research to be established.

  -Pixel counting and VBM showedconcurrent validityand it would be possible to replicate and check for this consistency in the future.
• What is a weakness about the type of data collected in Maguire's study?

  Lack of insight due to not collecting qualitative data may limit Maguire's full understanding of the results, reducing the usefulness
• How is Maguire's study ethical? (2)

  -The study was carried out according to the BPS guidelines so no ethical concerns - the participants were not deceived; they gave their informed consent (volunteer sample) and they were not harmed by the experience.

  -If we consider the cost-benefit analysis here the study is ethically worthwhile as there was no implications to the participants but the research was useful when developing rehabilitation programmes for brain-damaged patients.
• How is Maguire's study unethical?

  The process of having an MRI can cause anxiety and emotional harm, therefore protection of participants may have been somewhat violated.
• How did Maguire's study have high validity? (4)

  -Matched on gender, age, no psychological problems etc so high in internal validity as removes individual differences.

  -The volume differences in the hippocampus were established by two concurrently valid independent measures (VBM and pixel counting).

  -Correlations were also run to further support the findings from the experiment.

  -The researcher was blind to the conditions to previous researcher bias.
• How did Maguire's study have low validity? (2)

  -Low E.V as p's would not usually have an MRI scan in their daily lives as taxi drivers.

  
  

  -However, participants could not falsify their hippocampal volume so although in a lab environment there is no risk of demand characteristics so high internal validity.
• How did Maguire's study have high reliability? (4)

  -High internal reliability as highly standardised procedure e.g. all of the men had the same MRI scan and the same software was used to analyse their scans.

  -Scientific and objective equipment - MRI scanner, in order to check for consistency of data- high external reliability

  -Collected quantitative data which increases external reliability as if the study was replicated the same results could be gathered.

  -Test - retest reliability could be done due to quant data and scientific equipment.
• How did Maguire's study have low reliability?

  Due to the fact that the sample of men was quite small and no women were used, the external reliability can be seen as slightly low as there is no room for wide comparison of results, or comparison of female hippocampal volume.
• How is Maguire's study ethnocentric?

  There could be something unique to the experience of being a taxi-driver or completing the knowledge which could mean the results are specific to London taxi drivers only. We therefore need to be cautious about making the assumption that everyone's hippocampus has a similar capacity for brain plasticity.
• How is Maguire's study not ethnocentric?

  Could argue that spatial demands of the hippocampus in response to our environment is affected by the anatomy of our brains which is not ethnocentric as found in all humans from all cultures.
• Discuss nature/nurture in relation to Maguire’s research. (6)

  Maguire’s study is largely interactionist, as it addresses elements of bothnature and nurtureand how the two interact to cause brain plasticity. For example, she aimed to investigate how environmental experiences and stimuli can cause structural brain plasticity to theinnatevolume of the hippocampus. This interactionist aim allowed her to find that navigational experience, especially of frequently revisited locations, can cause an enlarged volume in the posterior hippocampus, illustrating that navigational experience can belearnt. This is astrengthof the study as it greatly enhances our understanding of how our environment can alter how ourinnate biological factorsdemonstrate themselves and change over time, encouragingpractical applicationssuch as brain training and using regions of the brain that you wish to exercise.

  However, such an interactionist approach to both nature and nurture may be seen as aweakness, as it removes the in-depth focus on one specific factor of brain plasticity. For example, Maguire was unable to focus solely on the role of the innate hippocampus in humans, as she also looked at how the environment led to changes in the structure of the brain, removing thescientific naturefrom the study in some way and the focused conclusions that could have been made about the hippocampus.
• Discuss to what extent Maguire's study is reductionist. (6)

  Maguire's study can be considered reductionist to some extent, however, it is largely a holistic study as it considers the interaction between nature and nurture when exploring structural brain plasticity. For example, Maguire found that the innate size of the hippocampus that we are born with, when interacted with the environment and navigational experiences, the volume can increase and structural plasticity can occur. This is a strength of the study, as looking holistically at brain plasticity can enhance peoples knowledge of how they can manipulate their environment e.g. by training their brains, in order to change the innate volume of their grey matter and become improved at a certain skill.

  However, the study can be seen as reductionist on some level, as the main focus is the biological and innate factor of the brain and how it can plasticise. For example, Maguire focuses mainly on how our physiology can change and grow by comparing 2 different groups of men, both who have different navigational experience. This is a weakness as a reductionist approach to research can be seen as deterministic, as Maguire suggests that the volume of your hippocampus can predetermine your navigational skills, removing choice from the individual.
• Discuss the scientific nature of Maguire's study (6)

  Maguire’s study can be consideredhighly scientificdue to the use ofobjective scientific equipment, allowing for quantitative measures. For example, each of the 16 taxi drivers and non-taxi drivers were given an MRI scan in order to measure the volume of their hippocampi, and objective software was used to measure this, VBM and Pixel counting. Both the scanner and the software cannot be misinterpreted or seen in a subjective manner. This is astrengthfor the study, as Maguire was able to consolidate very scientific conclusions regarding how our environment can alter the structure of our brain,increasing the reputation of psychology as a science.However, the objective and scientific nature of Maguire’s study is aweakness, as the lack of qualitative data reduces the insight we have about structural brain plasticity within the hippocampus. For example, we have no detail or explanation about the navigational experience of the different taxi driver or non-taxi drivers, therefore, we have no depth of understanding about how their own experiences may have impacted the plasticity of their brain. This reduces theusefulnessof the findings, as on some level, our understanding is reduced.