BACK AT HARVARD
when a thing is “good enough” is useless on this work—must
not overlook small differences. Requires discretion and alert¬
ness to distinguish factors entering into and causing defects. . . .
Standard is rigid and precise and operator requires attitude of
regular conformity more than personal decision.
The inspection of blades:
This work requires speed without a sense of haste. I mean,
doing rapidly, regardless of the flight of time. To insure this
self-reliance and sureness of decision are necessary. The eye
test is supplemented by a tactual and cutting test. The tactual
requires delicacy of touch. The action is a very light contact,
scarcely heavy enough to be called pressure, combined with
a gliding over the edge of a very small surface of the finger.
Operators easily learn to distinguish extreme roughness by a
granular feeling, but a small number distinguish between a slight
roughness, wTiich gives a sticky, clinging sensation of cutting,
in contrast to the quick cutting of the finest edges. In the
one, there is a perceptible feeling of width, which is lacking
on the sharpest blades. This same feeling of width is perceptible
to persons of the finest sensibility in separating dullness from
smoothness. . . .
Intelligent and careful response of this kind furnished
the psychologist with suggestive data and proved, more¬
over, that the offer of scientific help was enthusiastically
received in the world of affairs. Of course it was not the
professor’s intention to devise tests in his laboratory for
a razor-blade inspector or a silversmith or an engineer
or a salesman. The main issue was to determine a principle
by which any candidate for any industrial job might be
tested at any time. It was obvious that the possible
locomotive engineer of a railroad company cannot be pro¬
vided with two trains about to collide for the sake of test¬
ing his promptness and presence of mind; a possible
salesman cannot be provided with a horde of customers
to test his patience. Therefore it was necessary to repro¬
duce the situation in which the candidate was to act or
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