nt times. If ordinary college students work
at habit-formation at the highest point of concentration, they get the
best return for a period of about a half hour. It depends somewhat on
the amount of concentration required for the work and the stage of
fixation of the habit, _i.e._ whether one has just begun to form the
habit or whether it is pretty well fixed. For children, the period of
successful practice is usually much less than a half hour--five, ten,
fifteen, twenty minutes, depending upon the age of the child and the
kind of work.

The best interval between periods of practice is the day, twenty-four
hours. If one practices in the morning for a half hour, one can practice
again in the afternoon with nearly as much return as he would secure the
next day, but not quite. In general, practice is better, gives more
return, if spread out. To practice one day as long as one can work at a
high point of efficiency, and then to postpone further practice till the
next day, gives one the most return for the time put in. But if one is
in a hurry to form a habit, one can afford to practice more each day
even if the returns from the practice do diminish proportionately.

This matter has been tried out on the typewriter. If one practices for
ten half hours a day with half-hour rests between, one does not get so
much return for his time as he would if he should spread it out at the
rate of one or two half-hour practices a day. But by working ten half
hours a day, one gets much more efficiency in the same number of days
than if he should practice only one or two half hours a day. This point
must not be misunderstood. We do not mean that one must not work at
anything longer than a half hour a day. We mean that if one is forming a
habit, his time counts for more in forming the habit if spread out at
the rate of a half hour or an hour a day, than it does if put in at a
faster rate. Therefore if one is in no hurry and can afford to spread
out his time, he gets the best return by so doing, and the habit is more
firmly fixed than if formed hurriedly. But if one is in a hurry, and has
the time to devote to it, he can afford to concentrate his practice up
to five hours or possibly more in a day, provided that rest intervals
are interspersed between periods of practice.

There is one time in habit-formation when concentrated practice is most
efficient. That is at the beginning. In a process as complicated as
typewriting, so little impres