Atomic Habits: Tiny Changes, Remarkable Results

HOW LONG DOES IT ACTUALLY TAKE TO FORM A NEW
HABIT?
Habit formation is the process by which a behavior becomes progressively
more automatic through repetition. The more you repeat an activity, the
more the structure of your brain changes to become efficient at that activity.
Neuroscientists call this long-term potentiation, which refers to the
strengthening of connections between neurons in the brain based on recent
patterns of activity. With each repetition, cell-to-cell signaling improves and
the neural connections tighten. First described by neuropsychologist Donald
Hebb in 1949, this phenomenon is commonly known as Hebb’s Law:
“Neurons that fire together wire together.”
Repeating a habit leads to clear physical changes in the brain. In
musicians, the cerebellum—critical for physical movements like plucking a
guitar string or pulling a violin bow—is larger than it is in nonmusicians.
Mathematicians, meanwhile, have increased gray matter in the inferior
parietal lobule, which plays a key role in computation and calculation. Its
size is directly correlated with the amount of time spent in the field; the
older and more experienced the mathematician, the greater the increase in
gray matter.
When scientists analyzed the brains of taxi drivers in London, they
found that the hippocampus—a region of the brain involved in spatial
memory—was significantly larger in their subjects than in non–taxi drivers.
Even more fascinating, the hippocampus decreased in size when a driver
retired. Like the muscles of the body responding to regular weight training,
particular regions of the brain adapt as they are used and atrophy as they are
abandoned.
Of course, the importance of repetition in establishing habits was
recognized long before neuroscientists began poking around. In 1860, the
English philosopher George H. Lewes noted, “In learning to speak a new
language, to play on a musical instrument, or to perform unaccustomed
movements, great difficulty is felt, because the channels through which
each sensation has to pass have not become established; but no sooner has
frequent repetition cut a pathway, than this difficulty vanishes; the actions
become so automatic that they can be performed while the mind is

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otherwise engaged.” Both common sense and scientific evidence agree:
repetition is a form of change.
Each time you repeat an action, you are activating a particular neural
circuit associated with that habit. This means that simply putting in your
reps is one of the most critical steps you can take to encoding a new habit. It
is why the students who took tons of photos improved their skills while
those who merely theorized about perfect photos did not. One group
engaged in active practice, the other in passive learning. One in action, the
other in motion.
All habits follow a similar trajectory from effortful practice to automatic
behavior, a process known as automaticity. Automaticity is the ability to
perform a behavior without thinking about each step, which occurs when
the nonconscious mind takes over.
It looks something like this: