It would be interesting to standardize a longer series of problems designed to test a subject's comprehension of common physical relationships. In the first few months of life a normal child learns that objects unsupported fall to the ground. Later he learns that fire burns; that birds fly in the air; that fish do not sink in the water; that water does not run uphill; that it is easy to lift a leg or arm as one lies prone in the water; that mud is thrown from a rotating wheel (and always in the same direction); that a stone which is flying through the air swiftly is more dangerous than one which is moving slowly; that it is more dangerous to be run over by a train than by a buggy; that it is hard to run against a strong wind; that cyclones blow down trees and houses; that a rapidly moving train creates a stronger wind than a slower train; that a feather falls through the air with less speed than a stone; that a falling object gains momentum; that a heavy moving object is harder to stop than a light object moving at the same rate; that freezing water bursts pipes; that sounds sometimes give echoes; that rainbows cannot be approached; that a lamp seems dim by daylight; that by day the stars are not visible and the moon only barely visible; that the headlights of an approaching automobile or train are blinding; that if the room in which we are reading is badly lighted we must hold the book nearer to the eyes; that running makes the heart beat faster and increases the rate of breathing; that if we are cold we can get warm by running; that whirling rapidly makes us dizzy; that heat or exercise will cause perspiration, etc. Although the causes of some of these phenomena are not understood even by intelligent adults without some instruction, the facts themselves are learned by the normal individual from his own experience. The higher the mental level and the greater the curiosity, the more observant one is about such matters and the more one learns. Many items of knowledge such as we have mentioned could and should be standardized for various mental levels. In devising tests of this kind we should, of course, have to look out for the influences of formal instruction. CHAPTER XX INSTRUCTIONS FOR "SUPERIOR ADULT" SUPERIOR ADULT, 1: VOCABULARY (SEVENTY-FIVE DEFINITIONS, 13,500 WORDS) PROCEDURE and SCORING, as in previous vocabulary tests. At the "superior adult" level seventy-five words should be known. The test is passed by only one third of those at the "average adult" level, but by about 90 per cent of "superior adults." Ability to pass the test is relatively independent of the number of years the subject has attended school, our business men showing even a higher percentage of passes than high-school pupils. SUPERIOR ADULT, 2: BINET'S PAPER-CUTTING TEST