In the 1930s, many of the schools that participated in the Eight-Year Study of the Progressive Education Association (Aikin 1942) adopted critical thinking as an educational goal, for whose achievement the study’s Evaluation Staff developed tests (Smith, Tyler, & Evaluation Staff 1942).
Glaser (1941) showed experimentally that it was possible to improve the critical thinking of high school students.
Morevoer, the pilot being near the front of the boat, he would need some such guide as to its direction. This hypothesis was so much more probable than the others that I accepted it. It expands by increase of heat, or by decrease of pressure, or both.
I formed the conclusion that the pole was set up for the purpose of showing the pilot the direction in which the boat pointed, to enable him to steer correctly.” (Dewey 1910: 69-70; 1933: 92-93) : “In washing tumblers in hot soapsuds and placing them mouth downward on a plate, bubbles appeared on the outside of the mouth of the tumblers and then went inside. The presence of bubbles suggests air, which I note must come from inside the tumbler. Could the air have become heated after the tumbler was taken from the hot suds?
“I then tried to imagine all possible purposes of the pole, and to consider for which of these it was best suited: (a) Possibly it was an ornament.
But as all the ferryboats and even the tugboats carried poles, this hypothesis was rejected.
My mind went back to the subway express as quicker than the elevated; furthermore, I remembered that it went nearer than the elevated to the part of 124th Street I wished to reach, so that time would be saved at the end of the journey.
I concluded in favor of the subway, and reached my destination by one o’clock.” (Dewey 1910: 68-69; 1933: 91-92) : “Projecting nearly horizontally from the upper deck of the ferryboat on which I daily cross the river is a long white pole, having a gilded ball at its tip.
“In support of this conclusion, I discovered that the pole was lower than the pilot house, so that the steersman could easily see it.
Moreover, the tip was enough higher than the base, so that, from the pilot's position, it must appear to project far out in front of the boat.