In yesterday’s post, we saw that London cab drivers
had increased the amount of gray matter in the rear section of the frontal
lobes of their brains by stuffing them full of the details of the sights, sites
and streets of central London. Well, the amount of gray matter in the frontal
lobes has other effects too.
The reason that I bring this up is that the classic
London cab driver was always chatty and a fund of information. A touch of the
extrovert, perhaps. Personally, I’ve experienced some quite extroverted driving
when being late for a train, which included a U-turn in crowded traffic and
then the cab taking to the sidewalk to get past a local log-jam.
Coming to our aid today, Cremers et al from the Netherlands have put
another 65 healthy people into the big magnet and reported out in the Public
Library of Science (1). We should note that these weren’t cab drivers from
London, or elsewhere, but just representing a typical cross-section of people.
Jumping straight to the results, it was found that
those with larger volumes of their right amygdalas and orbitofrontal lobes (the
bits behind the forehead and eyes) were extroverts. The more gray matter, the
more extroverted. Recall that the OFC does the job of controlling your reward
and emotional behavior. Thus, it is also involved in your decision making.
A bigger amydala goes along with larger social
networks, good news, but can also be related to binge drinking. It also was an
indicator for sexual extroversion in men, although it had the opposite trend
with women.
If sending guys out to learn the streets of central
London beefs up their hippocampi, maybe it could be doing the same for their
OFCs and amygdalas. Extroverts are much less likely to suffer from depression.
Do you suppose that a cure might be found wandering around the backstreets of
central London until “The Knowledge” is firmly grasped? We need to get this
Dutch team looking at the fMRI pictures from yesterday’s study of London
cabbies.
