The method of this test series consists in putting the child into a well-defined situation and observing how he acts. The situation may consist partly in words or other noises impressing themselves upon his ears, or it may consist largely in visual sensations, or even in sensations of physical well-being in his own body. Under a given situation a normal child of a given age or older will act in a certain standard way. The measurement then is in terms of the age for which a given child’s reactions are typical. The test can best be given by one who is fairly familiar with the infant to be tested, although interest in having the child make a good showing should never be allowed to change one’s judgment of the facts as to the child’s performance. Another danger of too great familiarity is that the examiner may, without intention to do so, drill the child upon those things which are later to be required in the test. In so far as the parent knows what performances are to be included in the tests there is real danger that the child will be “coached up” on these things, even at as early an age as six months. _List of Typical Performances._ THREE MONTHS (3 tests, credit 1 month each) 1. Control of eyes (Both eyes look in same direction. Follows with eyes the movement of bright objects). 2. Hearing (Reacts with sudden start or scream to loud noises, such as slamming of door, hand clapping. Turns eyes or head in direction of less startling noises, such as opening of door, footsteps). 3. Muscular Control (Moves hand or toy directly to mouth without striking other parts of body and face. Grasps or curls fingers about rattle or pencil placed in hands). SIX MONTHS (3 tests, credit 1 month each) 1. Muscular Control (Balances head without support. Sits ten minutes or more when supported). 2. Self-Direction (Attempts to catch self when beginning to fall from sitting posture. Reaches out for toys and near-by objects. Attempts to pull self to sitting posture if given a hand to grasp). 3. Enjoyment (Plays longer and more persistently with one toy than with another. Laughs aloud when bounced on bed or when familiars indulge in strenuous exercise). ONE YEAR (6 tests, credit 1 month each) 1. Imitation of Movements (Can learn in half dozen trials to “wave bye-bye,” put hands above head, or hide face in hands). 2. Locomotion (Creeps toward desired objects, or stands beside a chair without other assistance). 3. Understanding (Looks at frequently observed objects when names are mentioned: dog, ball, mama, flowers). 4. Obedience (Understands and usually obeys simple commands: “Lie down! No, No! Spit it out!”). 5. Speech (Repeats simple syllables: “go, go; da, da; ma, ma; bye-bye”).