The fifth factor that might account for individual differences is environment. By environment we mean any influence brought to bear on the individual. The same difficulty has been met in attempting to measure the effect of environment that was met in trying to measure the effect of inner nature--namely, that of testing one without interference from the other. The attempts to measure accurately the effect of any one element in the environment have not been successful. No adequate way of avoiding the complications involved by different natures has been found. One of the greatest errors in the method of working with this problem has been found just here. It has been customary when the effect of a certain element in the environment is to be ascertained to investigate people who have been subject to that training or who are in the process of training, thus ignoring the selective influence of the factor itself in original nature. For instance, to study the value of high school training we compare those in training with those who have never had any; if the question is the value of manual training or Latin, again the comparison is made between those who have had it and those who haven't. To find out the influence of squalor and misery, people living in the slums are compared with those from a better district. In each case the fact is ignored that the original natures of the two groups examined are different before the influence of the element in question was brought to bear. Why do some children go to high school and others not? Why do some choose classical courses and some manual training courses? Why are some people found in the slums for generations? The answer in each case is the same--the original natures are different. It isn't the slums make the people nearly so often as it is the people make the slums. It isn't training in Latin that makes the more capable man, but the more intellectual students, because of tradition and possibly enjoyment of language study, choose the Latin. It is unfair to measure a factor in the environment and give it credit or discredit for results, when those results are also due to original nature as well, which has not been allowed for. It must be recognized by all those working in this field that, after all, man to some extent selects his own environment. In the second place, it must be remembered that the environment will influence folks differently according as their natures are different. There can be no doubt that environment is accountable for some individual differences, but just which ones and to what extent are questions to which at present the answers are unsatisfactory.
The investigations which have been carried on agree that environment is not so influential a cause for individual differences in intellect as is near ancestry. One rather interesting line of evidence can be quoted as an illustration. If individual differences in achievement are due largely to lack of training or to poor training, then to give the same amount and kind of training to all the individuals in a group should reduce the differences. If such practice does not reduce the differences, then it is not reasonable to suppose that the differences were caused in the first place by differences in training. As a matter of fact, equalizing training increases the differences. The superior man becomes more superior, the inferior is left further behind than ever. A common occurrence in school administration bears out this conclusion reached by experimental means. The child who skips a grade is ready at the end of three years to skip again, and the child who fails a grade is likely at the end of three years to fail again. Though environment seems of little influence as compared with near ancestry in determining intellectual ability per se, yet it has considerable influence in determining the line along which this ability is to manifest itself. The fact that between 1840-44, 9.4 per cent of the college men went into teaching as a profession and 37.5 per cent into the ministry, while between 1890-94, 25.4 per cent chose the former and only 14 per cent the latter, can be accounted for only on the basis of environmental influence of some kind.[16]
Another fact concerning the influence of environment is that it is very much more effective in influencing morality than intellect. Morality is the outcome of the proper direction of capacities and tendencies possessed by the individual, and therefore is extremely susceptible to environmental influences. We are all familiar with the differences in moral standards of different social groups. One boy may become a bully and another considerate of the rights of others, one learns to steal and another to be honest, one to lie and another to be truthful, because of the influence of their environments rather than on account of differences in their original natures. We are beginning to recognize the importance of environment in moral training in the provisions made to protect children from immoral influences, in the opportunities afforded for the right sort of recreation, and even in the removal of children from the custody of their parents when the environment is extremely unfavorable.
Though changes in method and ideals cannot reduce the differences between individuals in the intellectual field to any marked extent, such changes can raise the level of achievement of the whole group. For instance, more emphasis on silent reading may make the reading ability of a whole school 20 per cent better, while leaving the distance between the best and worst reader in the school the same. Granting that heredity, original nature, is the primary cause of individual differences in intellect (aside from those sex differences mentioned) there remains for environment, education in all its forms, the tremendous task of: First, providing conditions favorable for nervous health and growth; second, providing conditions which stimulate useful capacities and inhibit futile or harmful capacities; third, providing conditions which continually raise the absolute achievement of the group and of the race; fourth, providing conditions that will meet the varying original equipments; fifth, assuming primary responsibility for development along moral and social lines.
Concerning those individual differences of which heredity is the controlling cause, two facts are worthy of note. First, that human nature is very highly specialized and that inheritance may be in terms of special abilities or capacities. For instance, artistic, musical, or linguistic ability, statesmanship, power in the field of poetry, may be handed down from one generation to the next. This also means that two brothers may be extremely alike along some lines and extremely different along others. Second, that there seems to be positive combinations between certain mental traits, whereby the presence of one insures the presence of the other to a greater degree than chance would explain. For instance, the quick learner is slow in forgetting, imagery in one field implies power to image in others, a high degree of concentration goes with superior breadth, efficiency in artistic lines is more often correlated with superiority in politics or generalship or science than the reverse, ability to deal with abstract data implies unusual power to deal with the concrete situation. In fact, as far as exact measures go, negative correlations between capacities, powers, efficiencies, are extremely rare, and, when they occur, can be traced to the influence of some environmental factor.
Individuals differ from each other to a much greater degree than has been allowed for in our public education. The common school system is constructed on the theory that children are closely similar in their abilities, type of mental make-up, and capacities in any given line. Experimentation shows each one of these presuppositions to be false. So far as general ability goes, children vary from the genius to the feeble-minded with all the grades between, even in the same school class. This gradation is a continuous one--there are no breaks in the human race. Children cannot be grouped into the very bright, bright, mediocre, poor, very poor, failures--each group being distinct from any other. The shading from one to the other of these classes is gradual, there is no sharp break. Not only is this true, but a child may be considered very bright along one line and mediocre along another. Brilliancy or poverty in intellect does not act as a unit and apply to all lives equally. The high specialization of mental powers makes unevenness in achievement the common occurrence. Within any school grade that has been tested, even when the gradings are as close as those secured by term promotions, it has been found in any subject there are children who do from two to five times as well as others, and from two to five times as much as others. Of course this great variation means an overlapping of grades on each side. In Dr. Bonser's test of 757 children in reasoning he found that 90 per cent of the 6A pupils were below the best pupils of 4A grade and that 4 per cent of 6A pupils were below the mid-pupils of the 4A, and that the best of the 4A pupils made a score three times as high as the worst pupils of 6A. Not only is this tremendous difference in ability found among children of the same class, but the same difference exists in rate of development. Some children can cover the same ground in one half or one third the time as others and do it better. Witness the children already quoted who, skipping a grade, were ready at the end of three years to skip again. Variability, not uniformity, is what characterizes the abilities and rate of intellectual growth of children in the schools, and these differences, as has already been pointed out, are caused primarily by a difference in original nature.
There is also great difference between the general mental make-up of children--a difference in type. There is the child who excels in dealing with abstract ideas. He usually has power also in dealing with the concrete, but his chief interest is in the abstract. He is the one who does splendid work in mathematics, formal grammar, the abstract phases of the sciences. Then there is the child who is a thinker too, but his best work is done when he is dealing with a concrete situation. Unusual or involved applications of principles disturb him. So long as his work is couched in terms of the concrete, he can succeed, but if that is replaced by the x, y, z elements, he is prone to fail. There is another type of child--the one who has the executive ability, the child of action. True, he thinks, too, but his forte is in control of people and of things. He is the one who manages the athletic team, runs the school paper, takes charge of the elections, and so on. For principles to be grasped he must be able to put them into practice. The fourth type is the feeling type, the child who excels in appreciative power. As has been urged so many times before, these types have boundaries that are hazy and ill defined; they overlap in many cases. Some children are of a well-defined mixed type, and most children have something of each of the four abilities characteristic of the types. Still it is true that in looking over a class of children these types emerge, not pure, but controlled by the dominant characteristics mentioned.
The same variation is found among any group of children if they are tested along one line, such as memory. Some have desultory, some rote, some logical memories; some have immediate memories, others the permanent type. In imagery, some have principally productive imagination, others the matter-of-fact reproductive; some deal largely with object images that are vivid and clear-cut, others fail almost entirely with this type, but use word images with great facility. In conduct, some are hesitating and uncertain, others just the reverse; some very open to suggestions, others scarcely touched at all by it; some can act in accordance with principle, others only in terms of particular associations with a definite situation. So one might run the whole gamut of human traits, and in each one any group of individuals will vary: in attention, in thinking, in ideals, in habits, in interests, in sense discrimination, in emotions, and so on. This is one of the greatest contributions of experimental psychology of the past ten years, the tremendous differences between people along all lines, physical as well as mental.
It is lack of recognition of such differences that makes possible such a list of histories of misfits as Swift quotes in his chapter on Standards of Human Power in "Mind in the Making." Individual differences exist, education cannot eliminate them, they are innate, due to original nature. Education that does not recognize them and plan for them is wasteful and, what is worse, is criminal.
The range of ability possessed by children of the same grade in the subjects commonly taught seems not always to be clear in the minds of teachers. It will be discussed at greater length in another chapter, but it is important for the consideration of individual differences to present some data at this time. If we rate the quality of work done in English composition from 10 to 100 per cent, being careful to evaluate as accurately as possible the merit of the composition written, we will find for a seventh and an eighth grade a condition indicated by the following table: