PROCEDURE. Present the appropriate accompanying card with the lines in horizontal position. Point to the lines and say: "_See these lines. Look closely and tell me which one is longer. Put your finger on the longest one._" We use the superlative as well as the comparative form of _long_ because it is often more familiar to young subjects. If the child does not respond, say: "_Show me which line is the biggest._" Then withdraw the card, turn it about a few times, and present it again with the position of the two lines reversed, saying: "_Now show me the longest._" Turn the card again and make a third presentation. SCORING. All three comparisons must be made correctly; or if only two responses out of three are correct, all three pairs are again shown, just as before, and if there is no error this time, the test is passed. The standard, therefore, is _three correct responses out of three, or five out of six_. Sometimes the child points, but at no particular part of the card. In such cases it may be difficult to decide whether he has failed to comprehend and to make the discrimination or has only been careless in pointing. It is then necessary to repeat the experiment until the evidence is clear. REMARKS. As noted by Binet, success in this test depends on the comprehension of the verbal directions rather than on actual discrimination of length. The child who would unerringly choose the larger of two pieces of candy might fail on the comparison of lines. However, since the child must correctly compare the lines three times in succession, or at least in five out of six trials, _willingness to attend_ also plays a part. The attention of the low-grade imbecile, or even of the normal child of 3 years, is not very obedient to the suggestions of the experimenter. It may be gained momentarily, but it is not easily held to the same task for more than a few seconds. Hence some children who perfectly comprehend this task fail to make a succession of correct comparisons because they are unable or unwilling to bring to bear even the small amount of attention which is necessary. This does not in the least condone the failure, for it is exactly in such voluntary control of mental processes that we find one of the most characteristic differences between bright and dull, or mature and immature subjects. There has been little disagreement as to the proper location of this test. IV, 2. DISCRIMINATION OF FORMS PROCEDURE. Use the forms supplied with this book. First, place the circle of the duplicate set at "X", and say: "_Show me one like this_," at the same time passing the finger around the circumference of the circle. If the child does not respond, say: "_Do you see all of these things?_" (running the finger over the various forms); "_And do you see this one?_" (pointing again to the circle); "_Now, find me another one just like this._" Use the square next, then the triangle, and the others in any order.