Maguire (2000)

Question 1

What were Maguire’s 2 aims?

Answer 1

1) to investigate the extent of structural changes in the hippocampus of London taxi drivers as a result of extensive navigational experience
2) to see if there is a correlation between length of time of taxi driving experience and the measure of grey matter volume

Question 2

What was the sample of the experimental group?

Answer 2

• 16 males
• licensed as black taxi drives
• 1.5-42 years experience

Question 3

What are the weaknesses of the experimental sample?

Answer 3

• gender bias (only men = androcentric)
• culture bias (only London = ethnocentric)
• small (16) = lacks population validity - not representative or generalisable

Question 4

What was the sample of the control group?

Answer 4

• 50 brain scans
• obtained from a database
• right handed
• 32-62 years old
• healthy

Question 5

What was the sample design?

Answer 5

Matched Pairs

Question 6

What are the strengths of the sample design?

Answer 6

• reduced individual differences
• reduced chance of demand characteristics and order effects

Question 7

What are the weaknesses of the sample design?

Answer 7

individual differences still remain (not possible to completely remove)

Question 8

How were participants from the experimental and control groups matched?

Answer 8

• health
• handedness
• sex
• age

Question 9

What should be noted about one participant?

Answer 9

one taxi drivers data was not included in the correlational analysis as he had 42 years experience and was a clear outlier - would have skewed data

Question 10

What is the test about taxi driving called?

Answer 10

The Knowledge

Question 11

What is the premise of ‘The Knowledge’?

Answer 11

• intensive 2 year training course
• need to learn 25,000 streets
• general knowledge of major routes and points of interest

Question 12

What is the method?

Answer 12

• Quasi Experiment
  (+ correlation)

Question 13

What makes this study a quasi?

Answer 13

the sample were already London black taxi drivers or not

Question 14

What are strengths of a quasi experiment?

Answer 14

• reduced researcher bias
• ecological validity

Question 15

What are the weaknesses of a quasi experiment?

Answer 15

• lack of control = less reliable / valid
• cannot establish causality

Question 16

What is the DV?

Answer 16

volume of hippocampi including anterior (front); body (middle); posterior (back) regions

Question 17

What is the IV?

Answer 17

being a taxi driver or not being a taxi driver

Question 18

What are the two tests that measures the DV?

Answer 18

VBM and Pixel Counting

Question 19

What type of scientific measure was used?

Answer 19

MRI scans

Question 20

What is the design?

Answer 20

independent measures

Question 21

What are strengths of the design?

Answer 21

• reduced chance of demand characteristics and order effects

Question 22

What are the weaknesses of the design?

Answer 22

• individual differences

Question 23

What was the purpose of the MRI scan?

Answer 23

• shows 2D and 3D images of brain structure and grey matter

Question 24

What was used to analyse the results of the MRI?

Answer 24

VBM = Voxel Based Morphometry

Question 25

What did the VBM produce?

Answer 25

3D Grey Matter in brain regions

Question 26

What did Pixel Counting produce?

Answer 26

2D overall hippocampal volume of structures

Question 27

What is VBM?

Answer 27

an automatic computer software that 'normalises' the scans to eliminate overall brain size as an extraneous variable - gives output to the size of the hippocampi

Question 28

What is Pixel Counting?

Answer 28

image slices which are analysed by a blind researcher - counted to indicate the volume of the anterior, body, and posterior cross-sections of the hippocampi

Question 29

Why is Pixel Counting a strength?

Answer 29

- controlled conditions - blind researcher = objective - no researcher bias

Question 30

Why is using an MRI ethical?

Answer 30

antiinvasive and unharmful

Question 31

What were the key findings from the VBM?

Answer 31

- showed no significant differences between the brains of taxi drivers and controls - except for the hippocampi - taxi drivers had significantly more grey matter volume in the right and left posterior hippocampi - controls had more grey matter volume in the right and left anterior hippocampi

Question 32

What were the key findings for Pixel Counting?

Answer 32

- no significant differences between overall volume of the hippocampi = no other grey matter had been removed from any other areas of the brain - taxi drivers had significantly more volume in the left posterior hippocampi - controls had more volume in the right anterior and body of the hippocampi - suggests that taxi drivers have a different brain structure

Question 33

What were the key findings from the correlational analysis?

Answer 33

- positive correlation was found between length of time as a taxi driver and posterior hippocampal volume (0.6) - negative correlation was found between length of time as a taxi driver and anterior hippocampal volume - indicates that the brain changes over time to meet demands of being a taxi driver

Question 34

What type of data did Maguire collect?

Answer 34

Quantitative

Question 35

What are the strengths of this type of data?

Answer 35

- objective - easy to analyse and compare

Question 36

What are the weaknesses of this type of data?

Answer 36

does not provide detailed reasoning as to the WHY behind behaviour

Question 37

What were the conclusions?

Answer 37

- there are regionally specific structural differences between the hippocampi of London taxi drivers and controls - there is local plasticity in the structure of the brain as it adapts in response to prolonged environmental stimuli