Neuroplasticity, which is the brains ability to change continuously throughout a persons life was studied by Maguire et al (2000). The researchers wanted to determine whether differences in the brain anatomy are predetermined or whether the brain is susceptible to plastic changes, in response to environmental stimulation - in this case driving a taxi. Here the researchers collected MRI scans from 16 right handed male London taxi drivers who had all been driving for more than 1.5 years, as well as MRI's of another 50 right handed males who did not drive taxis (the control group). The MRI images were compared. It was found that due to the extensive training undergone by taxi drivers (known as "the knowledge") these had an increased grey matter compared to the control group. A correlation was also found between the amount of time spent as a taxi driver and volume in the right posterior hippocampus.Maguire et al's study into taxi drivers serves as an example of neuroplasticity as it demonstrates how due to the environmental demands placed on the taxi drivers, neuroplasticity took place in the form of an increased grey matter, which facilitates spatial memory.