For most of 20th century scientists believed that
brain develops during a critical period during early childhood and then remains
relative unchanged. However, in the last few decades it has been shown that many
aspects of the brain can be altered (or are “plastic”) even into adulthood. And
yet, we find it difficult to change our habits. We see that people don’t change
their views especially their core beliefs easily. This is what Norman Doidge refers
to as “Plastic paradox” in his book “The brain
that changes itself”. Doidge considers this riddle one of the most
important lessons of the book. If our brain is really like a play-doh, then why
is it so difficult to change? Let’s explore this riddle in this article.
image sources:
https://tcnl.bme.wisc.edu/projects/completed/tvss
One of my favourite stories from the book revolves around
the neuroscientist Paul Bach-y-Rita. In a now-famous experiment in 1960s he
demonstrated that vision can be substituted by other sensory input such as
stimulators touching the back. Bach-y-Rita published his result in Nature in
1969 and coined the term “You see with your brain, not with your eyes”. In this
experiment, he had a blind person sit on a dentist-kind-of chair. The back of
the chair was replaced with a matrix of mechanical vibrators. There was a
camera mounted on top. Depending on the object captured by the camera, certain
set of vibrators would touch the back. (see the picture) It was found out that the
visual cortex of the blind person’s brain began to process the input coming from
the skin (back stimulators) and the person began to “see” the objects. This demonstrated
that brain could reorganize itself.
Subsequently scientists have found that brain undergoes
massive reorganization when one falls in love for the first time and when one
becomes a parent for the first time. At the microscopic level, it has been
shown that every learning experience involves lasting changes to the brain. In
fact, every thought is changing the brain synapses at a microscopic level. Assuming
we have 50,000 thoughts a day, your brain is undergoing 50,000 microscopic
changes in a day. That’s a lot of change. Ideally, we should be in a good
position to change anything – quit smoking, follow a diet, stop worrying
unnecessarily etc. But that’s not our experience. What’s happening here?
To explain this “plastic paradox”, Doidge uses a metaphor originally
from the neuroscientist Pascual-Leone of Harvard. It says that the plastic
brain is like a snowy hill in the winter. When we slide down the hill for the
first time, we will create a small path. When we come down the second time, we
will find it easier to follow a path closer to the first one. And if we repeat
this enough, it would create a speedy track, kind of a highway. The highways
serve a useful purpose as we carry out umpteen tasks on auto-pilot such as
walking, talking, driving etc. However, the highways also pose a drawback. As
the brain gets used to using the highways, who wants to pave a new path? It is
too much of effort. That’s how we get stuck with our habits.
So what does one do? Well, Doidge doesn’t offer any solution
in his book. However, this is what I feel based on my experiments and I could
be wrong. A paradox gets resolved when attention is paid to the inherent
inconsistency. Perhaps a good place to start may be by paying attention to the
thinking process as it is sliding down the “speedy tracks” especially when it
is not serving any useful purpose such as the case of worry, guilt, blame etc. Who
knows? This might open up alternate paths. And that might take us to the
uncharted territory and lead to creative insights.
I found the book helpful in understanding various ways in which neuroscience is exploring the boundaries of brain's plasticity.
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