that the other will exist there too. Inasmuch as
the one of the two traits may be easily detected, while the other may
be hidden and can be found out only by long careful tests, it would be
valuable, indeed, for the employment manager to become acquainted with
such correlations as the psychologist may discover: as soon as he
becomes aware of the superficially noticeable symptom, he can foresee
that the other disposition is most probably present. To give an
illustration: in the interest of such measurements of correlations we
have studied in the Harvard laboratory the various characteristics of
attention and their mutual dependence.[18] We found that typical
connections exist between apparently independent features of
attention. Persons who have a rather expansive span of attention for
acoustical impressions have also a wide span for the visual objects.
Persons whose attention is vivid and quick have on the whole the
expansive type of attention, while those who attend slowly have a
narrow field of attention, and so on. Hence the manifestation of one
feature of attention allows us to presuppose without further tests
that certain other features may be expected in the particular
individual.

The problem of attention, indeed, seems to stand quite in the centre
of the field of industrial efficiency. This conviction has grown upon
me in my observation of industrial life. The peculiar kind of
attention decides more than any mental trait for which economic
activity the individual is adapted. The essential point is that such
differences of attention cannot be characterized as good or bad; it is
not a question of the attentive and of the inattentive mind. One type
is not better than another, but is simply different. Two workingmen,
not only equally industrious and capable, but also equally attentive,
may yet occupy two positions in which they are both complete failures
because their attention does not fit the places, and both may become
highly efficient as soon as they exchange positions. Their particular
types of attention have now found the right places. The one may be
disposed to a strong concentration by which everything is inhibited
which lies on the mental periphery, the other may have the talent for
distributing his attention over a large field, while he is unable to
hold it for a long while at one point. If the one industrial activity
demands the attentive observation of one little lever or one wheel at
one point, while t