Memorizing Makes Your Brain Bigger.

I’m reading Moonwalking with Einstein, a book about memory and how the author made it better. Facinating stuff so far, but this little tidbit deserves a blog post. I’ll never think about cabbies – at least London cabbies – the same way again.

“These studious cyclists are training to become cabdrivers. Before they can receive accreditation from London’s Public Carriage Office, cabbies-in-training must spend two to four years memorizing the locations and traffic patterns of all 25,000 streets in the vast and vastly confusing city, as well as the locations of 1,400 landmarks. Their training culminates in the infamously daunting exam called “the Knowledge,” in which they not only have to plot the shortest route between any two points in the metropolitan area, but also name important places of interest along the way. Only about three out of ten people who train for the Knowledge obtain certification.

That is a high bar to set for mere cabdrivers. Amazing.

The author then follows up with something my neuro-radiologist best friend and I were talking about the other day in Vegas. I’d asked if the often sited “we only use 10% of our brain” was true. He wasn’t sure exactly, but said it is more likely we only use 10% at a time. Then we talked a little about memory. I mentioned the 60 Minutes piece with the actor from Taxi who remembered every day of her life in detail, and how there were more people like her interviewed on the show.

Then we talked about the interesting thing they found out about those people. They did an MRI of their brains and found hypertrophy in the part of the brain associated with memory. But in the story they didn’t know which came first. Did they have extraordinary memories because they were born with the hypertrophy, or did remembering all that cause them to have the hypertrophy?

Well they did the same thing with London’s cabbies.

…she brought in 16 taxi drivers into her lab and examined their brains with an MRI…The right posterior hippocampus, a part of the brain know to be involved in spatial navigation, was 7% larger than normal in the cabbies – a small by very significant difference….The more years a cabbie had been on the road, the more pronounced the effect

So it looks like memorizing changes your brain. More to come as I keep reading.