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What then do the tests accomplish? I think we can answer this question best by starting with an illustration. Suppose you wished to judge all the pebbles in a large pile of gravel for the purpose of separating them into three piles, the first to contain the extraordinary pebbles, the second the normal pebbles, the third the insignificant pebbles. You have no scales. You first separate from the pile a much smaller pile and pick out one pebble which you guess is the average. You hold it in your left hand and pick up another pebble in your right hand. The right pebble feels heavier. You pick up another pebble. It feels lighter. You pick up a third. It feels still lighter. A fourth feels heavier than the first. By this method you can arrange all the pebbles from the smaller pile in a series running from the lightest to the heaviest. You thereupon call the middle pebble the standard pebble, and with it as a measure you determine whether any pebble in the larger pile is a subnormal, a normal or a supernormal pebble.

This is just about what the intelligence test does. It does not weigh or measure intelligence by any objective standard. It simply arranges a group of people in a series from best to worst by balancing their capacity to do certain arbitrarily selected puzzles, against the capacity of all the others. The intelligence test, in other words, is fundamentally an instrument for classifying a group of people. It may also be an instrument for measuring their intelligence, but of that we cannot be at all sure unless we believe that M. Binet and Mr. Terman and a few other psychologists have guessed correctly when they invented their tests. They may have guessed correctly but, as we shall see later, the proof is not yet at hand.

The intelligence test, then, is an instrument for classifying a group of people, rather than "a measure of intelligence." People are classified within a group according to their success in solving problems which may or may not be tests of intelligence. They are classified according to the performance of some Californians in the years 1910 to about 1916 with Mr. Terman's notion of the problems that reveal intelligence. They are not classified according to their ability in dealing with the problems of real life that call for intelligence.

With this in mind let us look at the army results, as they are dished up by writers like Mr. Lothrop Stoddard and Professor McDougall of Harvard. The following table is given:

4 % of the army were A men
9 % of the army were B men
16 1/2 % of the army were C+ men
25 % of the army were C men
20 % of the army were C- men
15 % of the army were D men
10 % of the army were D- men

But how, you ask, did the army determine the qualities of an "A" man? For an "A" man is supposed to have "very superior intelligence," and of course mankind has wondered for at least two thousand years what were the earmarks of very superior intelligence. McDougall and Stoddard are quite content to take the army's word for it, or at least they never stop to explain, before they exploit the figures, what the army meant by "very superior inelligence -sic-." The army, of course, had no intention whatever of committing itself to a definition of very superior intelligence. The army was interested in classifying recruits. It therefore asked a committee of psychologists to assemble from all the different systems, Binet and otherwise, a series of tests. The committee took this series and tried it out in a few camps. They timed the tests. "The number of items and the time limits were so fixed that five percent or less in any average group would be able to finish the entire series of items in the time allowed." (1) It is not surprising, therefore, that five percent or less (4 1/2 percent actually) of the army made a top score. It is not surprising that tests devised to pass five percent or less "A" men should have passed four and a half percent "A" men.

The army was quite justified in doing this because it was in a hurry and was looking for about five percent of the recruits to put into officers' training camps. I quarrel only with the Stoddards and McDougalls who solemnly talk about the 4 1/2 percent "A" men in the American nation without understanding how these 4 1/2 percent were picked. They do not seem to realize that if the army had wanted half the number of officers, it could by shortening the time have made the scarcity of "A" men seem even more alarming. If the army had wanted to double the "A" men, it could have done that by lengthening the time. Somewhere, of course, in the whole group would have been found men who could not have answered all the questions correctly in any length of time. But we do not know how many men of the kind there were because the tests were never made that way. (2)