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 are all involved in the successful accomplishment of each task. That point in the graded series of designs at which a child will begin failing to achieve further success, will be a rough measure of the development of his ability to attend, to adapt and to critically survey his general plan of performance and his ultimate accomplishment. In his discussion of the 'patience test' in the 1908 scale, and these words might as well apply to the block-design tests, Binet states: "It is a game, but at the same time a work of the intelligence. When one analyzes the operation it is found to be composed of the following elements: (1) Consciousness of the end to be attained, that is to say, a figure to be produced; this end must be understood, and kept in mind; (2) the trying of various combinations under the influence of this directing idea, which often unconsciously determines the kind of attempt which should be made; (3) judging the combination formed, comparing it with the model, and deciding if it resembles the other" (p. 198). If 'intelligence' involves the following mental operations; analyzing, combining, comparing, deliberating, completing, discriminating, judging, criticising and deciding, then the block-design tests may, with justice, be said to call upon the functioning of intelligence and to that extent they are a measure of that mental capacity.

(2) Increase in Score from Year to Year

As regards the second criterion, reference to Graph I. and to the various tables presented in this article will clearly demonstrate that this requisite is satisfied. The following, however, should be mentioned: At each life age a greater scatter or range in ability is noticeable than is the case with the Binet tests. Whether this phenomenon argues for reliability or not is left for discussion in the later monograph.

(3) Correspondence of Median Mental Ages

At each life age do the median mental ages obtained by the block-design tests correspond with the median mental ages obtained by the Binet tests? This question is an important one, and the extent of correspondence or deviation