Measure Your Mind: The Mentimeter and How to Use It

by Marion Rex Trabue; Frank Parker Stockbridge

Second, there must be prepared a standard or scale that is, primarily at least, adapted to the measurement of those particular qualities.

While it is, in practice, as has been heretofore pointed out, impossible entirely to segregate a particular mental quality or power from all the other abilities and capacities possessed by a particular individual, it is possible to select certain characteristics or abilities which, by the degree of their presence or absence, give a fair index of certain mental dimensions or capacities, and to devise tests that, when taken together, will measure these “key-abilities” and so reflect the general ability and capacity of the subject. The standards by which the results of such tests are gauged must necessarily, therefore, be such as have been shown, by experiment and experience, to give the closest possible measurement of the individual’s ability in these particular directions, by enabling the examiner to compare each subject’s performance under the test, or series of tests, with the records made under precisely similar tests by individuals and groups of known ability.

Mental capacity tests may be devised that will measure certain mental qualities of an infant who has not yet learned to talk, and by thus providing a comparison between this particular child’s capacities and the average of children of the same age, enable parents and physicians to determine in what direction efforts looking toward its mental development may most helpfully be undertaken. Thus we may test the infant’s power of observation and perception of shapes, of colours, of sounds and familiar objects before it is able to talk, measuring these by standards derived from experience with similar tests applied to a large number of healthy, normal infants, and by this means determining whether the subject is above or below the normal average for its age and if so in what respects.

At the other end of the scale of mental development, let us assume, is the possessor of the degree of Doctor of Philosophy from any of the great universities, since this is the principal degree the possession of which tends to show the possession of unusual mental powers, if not necessarily of wisdom. By applying to a large number of Ph.D.’s tests which are designed to require for their successful performance the utmost use of all their inherent mental abilities, and arriving at an average of performance by tabulating and comparing the degrees or percentages of perfection achieved by all of the individuals so tested, a standard is set up by which to measure the mental capacity of any individual or group of individuals of superior, or presumably superior, intelligence. By such a standard there may be measured also the mental capacity of men and women who have never seen the inside of a university, but whose education has been acquired in the course of their business and professional activities. This is so because what is measured is not acquired knowledge, but the ability to acquire knowledge, which is quite a different thing.

The simplest way to measure the capacity of a circular tank is to pump it full of water and then measure the water as it is drawn off. But it would be absurd to contend that because there has never been any water pumped into the tank it is therefore impossible to determine how much water it would hold. And what the Doctor of Philosophy has got out of his university course is comparable to the water in the tank. The university may have assisted, and if its faculty were competent undoubtedly did assist him, in discovering earlier in life than he otherwise would have discovered the actual capacity of his mental tank. But there are probably as many men of equal mental capacity whose mental tanks have never been filled with the particular kind of intellectual fluid that the Ph.D. carries about with him, whose capacity there is no other means of measuring than by the application of mental tests based upon the known capacities of Doctors of Philosophy.

The process of measuring the human mind is, indeed, precisely like the process of measuring an automobile by an engineer, as was pointed out in the preceding chapter. Back of the tests that are applied to the automobile to determine its abilities and capacities there must lie a mass of very definite, exact knowledge of all automobiles or all types of automobiles already in existence and whose capacities and limitations are already definitely known. It is of no service to ascertain that the engine cylinders are of four-inch bore and that the piston has a six-inch stroke, unless it is well known what the possession of a given number of cylinders of that particular bore and stroke signifies as to the ability or capacity of an automobile engine. That knowledge has been acquired by the observation and measurement over a period of years of the performance of many automobiles of varying cylinder sizes and number of cylinders, and the comparison of each size and type with all the others.

Similarly, it is of no service to apply a test of any kind to a human being unless we have, in the first place, determined just what particular abilities or capacities we want to measure, and, in the second place, possessed ourselves of knowledge as to the significance of these capacities, after they have been measured.

Here, again, the reader should keep constantly in mind the warnings set forth in the preceding chapter and try to think of mental abilities and qualities not as detached, separate, sharply defined parts of a mental whole (as the engine, transmission and bearings of the wheels of an automobile are detachable, separate entities) but rather as qualities so intermingled and connected by an infinite number of attachments to all the other mental qualities and abilities that no one particular ability can be measured separately or even positively delimited by any sort of test. Even if this could be done in the case of one individual, the process would have to be repeated in each separate, individual case, as in no two human beings is there found exactly the same combination and correlation of the manifold manifestations of conscious sensation and thought that together make up the human intelligence.

But having determined just what qualities and abilities it is desired to measure, we must set up a standard of measurement by which to compare the indicated ability of each individual examined, or we shall have nothing as a result of our test but a mass of information, of the significance of which we cannot possibly be aware. This standard, for some purposes, may be merely a composite record of the performances of a particular group or class examined simultaneously and under the same conditions. That is to say, if all that is required is to determine which individual of a group has the greatest ability in certain directions (and by inference the greatest capacity for further development along similar lines) then all that is necessary is to apply a test that will give a comparative measurement of the intelligence of this particular group. But if the purpose is to ascertain how a particular individual, or the average of a group of individuals, compares in particular kinds of capacity with the average or the most highly developed persons of the same status, education, occupation, or age, then the standard by which the subject must be measured must be one derived from the observation and measurement of the mental capacities of as large a number as possible of individuals engaged in all sorts of occupations and of all degrees and grades of educational attainment. And even where the purpose is merely to determine the relative qualifications and capacities of a particular limited group, it is as a matter of practice desirable, it might almost be said necessary, to compare the performance of each individual of the group with a standard previously fixed and determined as a result of a much broader series of observations and experiments than can be made within the limits of any group to which it is practicable to apply any given set of tests as a whole.

This is true for two reasons. First, without such an outside standard of comparison all that is determined by the application of even the most carefully devised tests to any group is that certain individuals are more and certain others are less able in particular ways than the average of the group. The net result is of service, but of nowhere near the service of a record of the same individuals’ performances graded in accordance with their approach to conformity with a universal standard. For example, one might take two, three, or a dozen automobiles on a speedway and quite readily determine which was the fastest and which the slowest, but unless one were possessed of certain standards of measurements that in themselves have no relation whatever to automobiles, the net result would be of little consequence and of no value whatever in comparing any one of these cars with another automobile that had not taken part in the particular test. In this case, two standards are requisite, namely, distance and time. The length of the course must be definitely ascertained. The time required for each automobile under test to cover the course must be accurately recorded.