Core study 20- Maguire (B) Flashcards
Taxi Drivers
Background
Where is the hippocampus in the brain?
In the limbic system (the emotional part of the brain)
Background
What does the hippocampus play an important part in?
The creation of memories especially, spatial memory and navigation
Background
What is the ‘knowledge’?
Black cab drivers required to have a detailed knowledge of the 25,000 streets within a six mile radius of Charing Cross
Background
What does the ‘knowledge’ consist of?
A written test on the first 80 routes, then an interview on the other 20 routes
Aim
What are the three aims of Maguire’s study?
- Show that the hippocampus in the human brain structure associates with spatial memory and navigation
- Examine direct affect of spatial experience of brain structure (plasticty)
- See if there’s a correlation between length of time as a taxi driver and hippocampal volume
Sample
How many taxi drivers were used in the study?
How were they matched?
16
All male, right handed, mean age 44, mean taxi career 14.3 years
Sample
How many non-taxi drivers were in the control group?
How were they matched?
50
Health, handedness, sex, mean age
Method
What kind of experiment was Maguire’s study?
Lab (quasi) experiment
Status of drivers were naturally occurring
Method
What was the IV?
Whether participant was a taxi driver or not
Method
What was the DV?
How was it measured?
Volume of hippocampi including their anterior, body and posterior
MRI scans using VBM and pixel counting
Procedure
What did Maguire do in order to look at brain structure?
Carried out MRI scans on all participants
Procedure
How were the MRI scans assessed?
- VBM
- Pixel counting
Procedure
What is VBM briefly?
Eliminates overall brain size to identify differences in grey matter density in different regions of the brain
Procedure
What is pixel counting briefly?
Compared the volume of anterior and posterior cross-sections of taxi drivers’ hippocampi with the non taxi drivers
Procedure
How was observer bias reduced?
Analysed by one experienced person, who was blinded to VBM results and driver status
Results- VBM
Where did volume increase in the taxi drivers’ hippocampi?
In the right and left posterior hippocampi (the back end)
Results- VBM
Where did the volume increase for non-taxi drivers?
In the right and left anterior hippocampi (the front)
Results- Pixel counting
Which group had greater posterier hippocampal volume?
Taxi drivers
Results- Pixel counting
Which group had greater anterior hippocampal volume?
Non taxi drivers (control group)
Results
What type of correlation was shown to be present?
There was a significant positive correlation between length of time as a taxi driver and volume of posterior hippocampus
Conclusions
What is the hippocampus responsible for?
Navigational memory in humans
Conclusions
What can environmental stimulus change?
Volume of the hippocampus- right posterior is linked to navigation
GREEDUM
How can generalisability be argued as a weakness?
16 taxi drivers were all male (androcentric), right handed and matched on age ranges
GREEDUM
How can reliability be argued as a strength?
16 taxi and 50 non-taxi all had brain scan using same MRI to show physical brain structure and grey matter density
GREEDUM
How can data be argued as a weakness?
Positive correlation- quant data doesn’t help show cause and effect
GREEDUM
How can ecological validity be argued as a strength?
MRI scans carried out and analysed using VBM and pixel counting- true to real life
