that of the
masons, whose function has also been performed for thousands of years,
and yet which did not find a real adaptation to the psychical factors
until a systematic time-measuring study was introduced. A manufacturer
who sells an improved pan or mixing-spoon or broom expects success if
he brings to the market something the merits of which are evident and
make the housewife anticipate a decrease of work or a simplification
of work, but the development of scientific management has shown
clearly that the most important improvements are just those which are
deduced from scientific researches, without at first giving
satisfaction to the laborers themselves, until a new habit has been
formed.

Perhaps the most frequent technical activity of this simple kind is
sewing by hand, which is still entirely left to the traditions of
common sense, and yet which is evidently dependent upon the interplay
of many psychical factors which demand a subtle adaptation to the
psychical conditions. To approach, at least, this field of human labor
a careful investigation of the psychophysics of sewing has been
started in my laboratory.[33] The sewing work is done, with the left
hand supported, and the right hand connected with a system of levers
which make a graphic record of every movement on the smoked surface of
a revolving drum. For instance, we begin with simple over and over
stitches, measuring the time and the character of the right hand
movements for 50 stitches under a variety of technical conditions. The
first variation refers to the length of the thread. The thread itself,
fixed at the needle's eye, varied between 3 feet and 6 inches in
length. Other changes refer to the voluntary speed, to the number of
stitches, to fatigue, to external stimuli, to attention, to methods of
training, and so on, but the chief interest remains centred on the
psychical factors. We are still too much at the beginning already to
foresee whether it will be possible to draw from these psychophysical
experiments helpful conclusions. The four young women engaged in this
laboratory research will later extend it to the psychological
conditions of work with the various types of sewing-machines.

XV

THE ECONOMY OF MOVEMENT

The study of the technical aspect of labor can nowhere be separated by
a sharp demarcation line from the study of the labor itself as a
function of the individual organism. Many problems, indeed, extend in
both directions