of breaking habits.

The two great laws of habit formation are the laws of exercise and
effect. These laws apply in all cases of habit formation, whether they
be the purposeless habits of children or the purposive habits of
maturity. The law of exercise says that the oftener and the more
emphatically a certain response is connected with a certain situation,
the more likely is it to be made to that situation. The two factors of
repetition and intensity are involved. It is a common observance that
the oftener one does a thing, other things being equal, the better he
does it, whether it be good or bad. Drill is the usual method adopted by
all classes of people for habit formation. It is because of the
recognition of the value of repetition that the old maxim of "Practice
makes Perfect" has been so blindly adhered to. Practice may make
perfect, but it also may make imperfect. All that practice can do is to
make more sure and automatic the activity, whatever it is. It cannot
alone make for improvement. A child becomes more and more proficient in
bad writing or posture, in incorrect work in arithmetic and spelling,
with practice just as truly as under other conditions he improves in the
same activities. Evidence from school experiments, which shows that as
many as 40 per cent of the children examined did poorer work along such
lines in a second test than in the first which had been given several
months earlier, bears witness to the inability of mere repetition to get
"perfect" results. To get such results the repetition must be only of
the improvements. There must be a constant variation towards the ideal,
and a selection of just those variations for practice, if perfect as
well as invariable results are to be obtained.

The amount of repetition necessary in the formation of any given habit
is not known. It will, of course, vary with the habit and with the