Page 191 - Deep Learning

174 Adaptation

But this verbal circle is not explanatory. Mindful scrutiny rends the veil of
familiarity and reveals a paradox.
The novice cannot know how to behave vis-à-vis an unfamiliar task, except
in a very general way. if he needs to practice, he has not yet mastered the task
well enough to perform it appropriately, correctly or successfully, or at least not
to his satisfaction. But if his performance is flawed or incomplete, why does
practice not engender a flawed or incomplete skill? if the learner repeatedly gen-
erates an incorrect sequence of actions, why does that sequence not become a
habit, entrenched in memory in such a way that the learner is doomed to repeat
it forever? if a novice car driver pulls out of a driveway in front of another car
50 times, surviving by the grace of other drivers’ short reaction times, why does
this not produce the habit of pulling out of the driveway without looking? if the
diligent piano pupil repeatedly plays Mozart’s piano sonata no. 14 incorrectly,
why does this behavior not wear smooth the corresponding path in the brain,
ensuring that every future performance will depart from the composer’s inten-
tion in equal measure? Why does the repetition of an incomplete and erroneous
performance result in improvement?
practice is not only sufficient but also necessary for the mastery of skills
of even modest complexity. A person cannot learn a new skill by first listening
to a verbal description of how the task is to be done, and then perform it in
a competent manner the very first time. if this were possible, driving schools
would soon go out of business, because teaching a novice to drive a car would
take 15 minutes. Airline companies would rejoice in cheap pilot training, and
the military could save on boot camp. But even when a novice has studied the
relevant task instructions to the point of being able to recite them verbatim,
he cannot therefore perform the target task perfectly and unhesitatingly the
first time he attempts it. English is not a programming language for the human
mind. A satisfactory theory of skill acquisition should explain why this is so.
A satisfactory theory must also explain why improvement during
practice is gradual. on each attempt, each practice trial, the performance
improves by a small amount, and many trials are typically required before
a new skill has been mastered. observe a novice driver operating a stick
shift. He handles the car jerkily; the individual actions are uncoordinated,
sometimes with audible effects on the gearbox; his attention is located on the
road in front when it should be on the rearview mirror and vice versa; and
so on. in general, novice behavior is characterized by bad timing, clumsi-
ness, errors and mistakes, frequent need to backtrack, hesitation, poor spa-
tial coordination, repetitions and slow and inaccurate task completion. in
the course of practice, the task comes to be performed with fewer errors and