The brain has forever startled the scientists. The power of the 'thing between our ears' is yet to be unraveled completely. One of the emerging branches in neuroscience is the study of memory - cognitive psychology.
The hippocampus of the brain is a structure embedded in the temporal lobe of each cerebral cortex. It is mainly concerned with learning and memory - spatial memory to be precise.
People believe that after a certain age the brain stops growing. However, recent studies have proved this wrong. Neuroplasticity is the process by which brain neurons form new connections whenever we learn something new or even when we make a mistake. The more you learn, the more your brain evolves and the more your hippocampus enlarges. The same thing was noticed in the brains of the cab drivers of London. But before delving into the nitty-gritties of the study, let's address the most pertinent question - why the cab drivers of London of all?
(The image is not owned by the publisher. No copyright violation intended. It has been taken from: https://www.wiley.com/learn/jossey-bass/images/what-the-black-cab-drivers-of-london-taught-us-about-learning-and-ability.jpg)
The cab drivers of London have to go through a very stringent process wherein they have to learn all the streets, which usually takes three to four years, in a 10-kilometre radius on a moped, and pass an exam only after which can they be issued a license. (Fun fact: In London, travelling in a black cab will cost you double the amount of travelling in an Uber. The cab drivers say this is because of 'The Knowledge' of the streets). This is where their spatial memory kicks in.
(Eleanor Maguire, a neuroscientist at University College London, who pioneered the study. The image is taken from: https://upload.wikimedia.org/wikipedia/commons/d/dd/Professor_Eleanor_Maguire_FMedSci_FRS.jpg . No copyright violation intended.)
The study was conducted by Eleanor Maguire, a neuroscientist at UCL, along with her colleague Katherine Woollett, who tracked the growth of the hippocampi of aspiring taxi-drivers for a period of four years using Magnetic Resonance Imaging (MRI).
For the experiment, 79 aspiring cab-drivers were followed while 31 people of the same age, education were kept as control (i.e., who were not aspiring drivers). Initially, all 110 people had hippocampi of more or less the same size.
Four years later, 39 out of the 79 aspirants had passed the exam. Maguire now saw that the successful aspirants now performed better on a memory test than those who failed. She attributed this to an enlarged hippocampi in the brains of those who passed.
However, a when the 79 aspirants were given another test, now a visual memory one, known as the 'Rey-Osterrieth Complex Figure Test' (where they were shown a complex a doll house and told to sketch it from memory after 30 minutes), Maguire et al. found that the people who failed did much better than those who passed. They concluded that the posterior hippocampi of the successful aspirants had enlarged at the expense of the anterior (front) hippocampi indicating a possible trade-off as a consequence of the preparation for the test. However, the function of the anterior hippocampus still remains mysterious.
To conclude, we see that the brain is capable of performing amazing feats and the main characteristic which is responsible for this is neuroplasticity. The organ, whose powers leave the scientists amazed, can be utilized to achieve things beyond human comprehension, and the London Cab Driver Experiment is a conclusive yet astounding proof of this.