The significance of reflective judgments in increasing human efficiency was manifested in a striking manner by the following experiment. A group of individuals were tested as to their ability to solve a number of mechanical puzzles. The time required for each individual was recorded. The subjects then described as completely as possible how they had solved the problem (worked the puzzle). In some instances the subjects kept trying blindly, till by accident they hit upon the right method. In such cases the second and third trials might take as long or even longer than the first trial. If, however, the subject had in mind the right principle or principles for solving the problems, the time required for succeeding attempts fell abruptly. Curve A of Figure 6 is a graphic representation of the results of A with one of <p 291> the puzzles. To solve the problem the first time required 1476 seconds. While solving it this first time A discovered a principle upon which success depended. The second attempt consumed 241 seconds. While solving the problem this second time he discovered a second principle. With these two principles in mind succeeding attempts were rendered rapid and certain. Another young man, B, in solving his problem. (Chinese Rings Puzzle) succeeded after working 1678 seconds. At the completion of this successful attempt he had in mind no principle for working it. The second trial was not so successful as the first and lasted 2670 seconds. With succeeding trials he reduced his time but not regularly and was still working ``in the dark.'' His method was one of extreme simplicity and probably not different from the ``try, try again'' method employed by animals in learning. The results of his first ten trials are graphically shown in Curve B of Figure 6. A comparison of Figure 6 with the five <p 292> {illust. caption = FIG. 6.} <p 293> figures of Chapter X will show how rapidly increase of efficiency is when dependent upon judgments as contrasted with improvement dependent upon habit. A judgment once having been made may be utilized again and again. The process of applying these preformed judgments is known as an intuitive or perhaps better called an expert judgment. _Expert judgments_ Just as appropriate concrete experiences determine the nature and the range of practical judgments, and as the formation of generalizations, abstractions, and principles determine the possibilities of reflective judgments, so the actual formation of the practical and reflective judgments determine the nature and the range of the intuitive or expert judgments.