Maguire

• Background: Previous research by Blakemore and Cooper

  Previously, Blakemore and Cooper examined functional brain plasticity whereas Maguire wanted to examine structural brain plasticicty
• Background: the hippocampus

  She wanted to investigate the hippocampus, which is a major part of the limbic system in charge of navigation and spatial memory
• Background: previous research in animals suggesting the hippocampus grows

  Previous research has been conducted on animals, e.g species of birds have been shown to have enlarged hippocampi volume when they migrate as they navigate to different parts of the world
• Background: inspiration for Maguire

  However, Maguire wanted to expand on this by assessing structural brain plasticity in London taxi drivers, where she compared their hippocampal volume to a control group of non-taxi drivers to see if their hippocampus enlarges in response to navigating around London
• More on hippocampus

  human limbic system is involved with behaviours that satisfy certain motivational, navigational, learning and emotional needs + spatial memory (fighting/feeding/escape/mating)

  in some species hippocampus volume enlarges especially during seasons when spatial ability is required the most, research has shown increased hippocampus volume in mammals + birds who show behaviour requiring spatial memory e.g food storing
• What has past research not shown

  • whether differences in brain structure is susceptible to plastic change in response to environmental stimulation
  • the precise role of the hippocampus in humans
  • whether the human brain responds to experiences requiring spatial memory in the same way as smaller mammals + birds

  Maguire aimed to show the hippocampus in the human brain is the structure associated with spatial memory + navigation
• Aim

  to investigate the differences in the brains of London taxi drivers and a control group who were not taxi drivers

  interested in if any differences would be observed in the volume of the hippocampus of London taxi drivers + the control group. by studying these potential differences Maguire was also investigating the possible structural plasticity of the human brain
• Why were London taxi drivers used

  because their jobs involve spatial awarness
• Sample

  
• Research method + design

  Quasi experiment

  Matched participants with independent measures (controls for imdv diffs)

  naturally occurring IV = whether the Ps were licensed London taxi drivers or not

  DV = the volume of the hippocampi including the anterior, posterior + body regions as measured by MRI scans of P's brains using VBM technology + pixel counting
• What else did Maguire do

  conducted a correlational analysis of the size of the hippocampus of the taxi drivers + the length of time that they had been in their profession to see if hippocampus volume increased with time
• Strengths of sample

  + control over indv diffs = all right handed, controls for indv diffs in brain structure between left + right handed people. all similar age so their brains have fully developed but they are not too old that deterioration/memory loss has begun. all healthy = controls brain abnormality/illnes impacting their spatial memory

  + range of experience so we can see how plasticity differs depending on length of time as taxi driver
• Weaknesses of sample

  -cannot generalise to left handed people

  -androcentric = can't generalise findings into structural brain plasticity of hippocampus to women

  -small sample size = don't look at brains of all humans that navigate = can't look for external reliability
• Example sample question

  
• Example Q: Outline a weakness of the research method used in Maguire's study

  IV is naturally occurring so Ps can't be randomly allocated so indv diffs aren't controlled = naturally occurring IV of if Ps are a taxi driver or not so we cannot randomly allocate Ps to group + indv diffs such as Ps natural ability to remember which could confound results = low IV, not truly measuring diffs in the volume of the hippocampus in taxi drivers + a control group of non-taxi drivers
• Procedure pt1

  
• Procedure pt2

  
• Controls

  • MRI scans were analysed by expert analysis who was blind to whether the scan was of a taxi driver or non-taxi driver + not analysed by Maguire = controls researcher effects
  • matched pairs design = controls individual differences
  • controlled setting of a lab = controls situational variables
• Example Q: Outline on control + its importance (4)

  The MRI scans of the London taxi drivers and non-taxi drivers hippocampus were analysed by an expert analyst who was blind to whether the scan was a taxi driver or a control + they weren't analysed by Maguire. Controls for researcher effects + reduces the risk of bias as they might've interpreted the scans of the hippocampus differently if they knew which condition the scan was from = high IV
• Findings + conclusions

  
• Link to key theme Q: what, who, how

  W = aimed to investigate structural brain plasticity in the hippocampus of the brain by looking for differences in hippocampal volume between London taxi drivers + a control group of non-taxi drivers

  W = 16 male taxi drivers + 50 male non-taxi drivers who were all healthy, right handed + matched on key characteristics to control for individual differences

  H = compared the hippocampus volume of taxi drivers + the control group using MRI scans of their brains which were analysed by VBM analysis + pixel counting
• Link to key theme Q: finding, link

  F = found that the London taxi drivers had a significantly greater posterior hippocampus volume than the non-taxi drivers

  L = links to key theme of brain plasticity as the environmental demand of navigation required for London taxi drivers caused their brain to structurally plasticise + the volume of their posterior hippocampus to increase
• Link to approach Q

  • environment an individual is in can alter how genetics are demonstrated -> London taxi drivers' hippocampus posterior volume was significantly greater than non-taxi drivers, showing evidence of structural brain plasticity in response to their environmental demand of navigation around London
  • biological basis -> Maguire studies structural brain plasticity of London taxi drivers compared to a control group which links to biological approach as the Ps are born with the ability to develop navigational skill through biological basis
• Evaluation table

  
• What debates does Maguire link to

  • determinism = suggests the taxi drivers hippocampi volume is predetermined by their experiences in their role which involves regular use of spatial navigation
  • situational = explains differences in hippocampus volume due to situational factors e.g the environment the taxi drivers are in where they use spatial navigation a lot