Social Psychology: An Analysis of Social Behavior

Chapter 9: Individual Differences and Social Behavior

Kimball Young

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A. Variability in Nature.

Variation in nature is well recognized. No two organisms look or act exactly alike. Differences are found, upon measurement, to exist in the various single organs of the body— in heart, lungs, size of brain, length of bones, etc. Also, when we measure such total contours as weight or height, we find the same thing to be true.

In line with popular statement people do not seem to be born equal in every respect. Neither do they, in spite of democratic theory, acquire equality. Variability among people in physique, temperament, and intelligence, as well as in wealth and social position, is self-evident.

1. Measures of Individual Differences. —  When we take any samples to measure people in regard to any given trait or group of traits, we find that these differences may be laid out on the scale of units and be dealt with conveniently by statistical devices. In a great many physical and psychological traits the differences seem to distribute themselves in somewhat the same form that chance throws of dice or coins would, or shots at a bulls-eye from a rifle or cannon. The form of this distribution is familiar to us as the bell-shaped Gaussian or normal probability curve. We find that the big bulk of individuals cluster around the central tendency of this curve. The measures of central tendency we call averages. The most commonly used of these are the mode, median, and arithmetic mean. The mode is that measure on the scale that contains the most items. The median is the middlemost measure of the entire group considered in terms of distribution from highest to lowest measure. The arithmetic mean is the average determined by taking, mathematically, the total magnitude of the various measures divided by the number of cases or the sample.

We are concerned, however, not with how distributed measures of persons summarize themselves into averages, but rather with the variability f these measures over the scale. We are concerned, in other words, with


Figure 4 showing Normal Probability Curve

the spread-out-ness of the differences. There are a number of measures of variability. The crudest way to express variability is to state the total range of cases, that is, the stretch from lowest to highest measure represented in one's sample. Mathematically, more accurate measures are average or mean variation, standard deviation, quartile deviation, and probable error. We shall not discuss here the methods of computing these. We need only point out that the first depends on the straight arithmetic mean of the deviations from the arithmetic mean or median. The second is secured by computing "the square of the arithmetic mean of the squares of the deviations from the average of the distribution." If on a normal probability curve "a distance equal to the standard deviation is laid off on each side of the mean, and ordinates are erected from the base line to the curve, that between the curve, the ordinates, and the base line will be included 68.26 per cent of the measures represented by the total area." [1]

The quartile deviation when laid off on each side of the central tendency or average includes one half of the measures, in the normal probability curve. The quartile deviation equals the probable error if the curve is "normal." In other words, we are able statistically to secure uniform measures of both central tendency and variability. This enables us to compare groups with groups, as well as to relate the individual or any percentage of individuals to the distribution of

(177) the entire group under consideration. It is not our purpose to discuss the statistics of variability, but to expose the existence of individual differences and to indicate rather briefly the place which these differences occupy in social behavior.

It should not be imagined that all forms of variation fall under the Gaussian curve. Distributions of incomes and of wealth certainly do not. Differences in public opinion seem often to be bi-modal or multi-modal, and it is doubtful if even such psychological features as emotional differences easily lend themselves to treatment under the normal probability curve. In all of these various distributions, nevertheless, individual variability shows itself in measurable form.

B. Deviations in Physical Traits.

Perhaps the most obvious individual differences exist in matters of physique. If any group of persons is measured for height, some will be short, others tall, and the rest, between these extremes, will range above and below an average figure. So, with weight, this same group will range from persons heavy to light in weight, clustering for the most part around a central tendency. These deviations rest upon heredity, maturity, and environmental conditioning. The law of filial regression enunciated by Galton indicates one set of heredity factors. Children of tall parents tend, on the average, to be shorter than their parents, while children of short parents tend to be taller than their parents. Children of one tall and one short parent fall in the average height between the extremes of parental height. Yet growth factors are partially determined by other than hereditary influences. Nutrition plays a distinct part. Statistics show that the economically depressed classes average shorter in height and lighter in weight than the wealthier classes. A long-time change in height and weight was exposed in a study of Ammon in Germany in which he found that recruits from certain sections tended to be taller and heavier in more recent times, due, apparently, to an improved standard of living.

1. Growth Rates.— There have been a great number of studies of rates of growth, in terms not only of height and weight, but of various internal organs as well. Mane of the earlier studies are open to criticism because they were made of inadequate samples of the general population. Moreover, many studies have been made, not of the same individuals over long periods of time, but of different age groups, on the assumption that the

(178) norms for any given age remain more or less constant. That is to say, the children now ten years old will, one year hence, be in substantially the same position, as to traits, as are the children eleven years old now. Correlations of various rates of growth have been attempted, but, as Ellis points out, "size and function do not necessarily go together," so that correlations of physique with physiological, psychological, or social functions are open to question.

An examination of the data on rates of growth of various organs, or of height and weight, indicate that rates differ tremendously throughout the period from birth to maturity. During the fetal stage, growth is very rapid indeed. During the first three years of life after birth, this high rate continues at least for some organs. In the first year the weight at birth is trebled. From that point on the rate of increase falls off to zero. Sometimes an actual decrease in weight occurs in old age. On the whole, growth in height is slower and continues at a more uniform rate than does increase in weight. The growth of the brain increases markedly throughout the first five or six years of life, and from that point on shows only a slight increase in gross weight.

Growth processes are by no means symmetrical. There are seasonal variations, and at puberty there are, in some organs at least, decided changes in rate. For instance, at birth the ratio of heart size to size of arteries is 25 to 20, at the beginning of puberty it is 140 to 50, at maturity, 290 to 61. At eight years of age, the muscles make up 27 per cent of the total body weight; at fifteen, 32 per cent, and at sixteen, 44 per cent, which is practically that of the adult. Many of the internal organs show distinct acceleration at adolescence. The most obvious changes occur in the sex organs, but the heart, liver, and kidneys, among others, show distinct spurts in rate of growth. The whole physical change at adolescence illustrates very well the differences in developmental rates. Some boys come into puberty as early as twelve and a half years, others do not reach this stage until seventeen or even eighteen years. Crampton distinguished three stages in the development of puberty. Pre-pubescent, pubescent, when the actual shift to sexual maturity took place, and post-pubescent. The following table covering the ages from twelve and a half to eighteen indicates the differences, in percentages, of development.

2. Sex Differences in Physical Growth.— Rates of growth differ also between the sexes. This is true in regard to height, weight, and internal or-

Table 4: Showing Age of Pubescence in Boys [2]
Age in Years Pre-pubescent Pubescent Post-pubescent
Per cent Per cent Per cent
12.5— 13.0 69 25 6
13.0— 13.5 55 26 18
13.5— 14.0 41 28 31
14.0— 14.5 26 34 40
14.5— 15.0 16 24 60
15.0— 15.5 9 20 70
15.5— 16.0 5 10 85
16.0— 16.5 2 4 93
16.5— 17.0 1 4 95
17.0— 17.5 0 2 98
17.5— 18.0 0 0 100

-gans. The following quotation from Woodrow from the findings of Pryor on the growth of the bones, as measured by carpal ossification, offers an illustration of variability between the sexes:

In round figures, he [Pryor] finds the following differences: From the age of one to the age of two, the difference in anatomical age is about one-half year. Anatomically, the girl of one and a half years is as old as the boy of two. This difference gradually increases. At the age of four the girl is anatomically as old as the boy of five. By the age of seven and a half the girl is as old anatomically as the boy of nine; and by the age of ten and a quarter she is as old as the boy of twelve and three-quarters. This latter difference agrees with that displayed at puberty, with respect to which we may say that the girl of twelve and a half is as old as the boy of fifteen.[3]

Physical variations exist between the sexes as well as within each group. While there are extreme differences within the sexes and while dietary fads and occupation make for deviations, it would seem that adult males tend to muscularity, women to obesity. Man is inclined to be angular in general bodily form, woman to be more curved in her contours. The bones of men are heavier than those of women. And bodily organs differ in proportion between the sexes.

As we shall observe, these bodily differences are not without importance in social behavior. While psychological differences and social and cultural

(180) divergences are significant, we can never escape the fact that variations in both size and function of the physical organs are basic to many other differences between persons, and perhaps, also, between the sexes.

C. Variation in Psychological Characteristics.

When we turn to examine the evidence on individual differences in psychological traits, again we find that the factors of heredity, growth, and environmental conditioning all play a part. Just how to untangle from the skein of life the precise threads which determine how much of the variation is due to one set of factors and how much to another, has baffled the best students of psychology and education for at least two generations. If we recall our fundamental standpoint that the forces of heredity and environment seem to interlock and to be, in fact, interdependent, we need not take part in this somewhat fruitless controversy. Often environmental forces determine what seems at first sight to be due to heredity. Boas remarks:

I am convinced that a test, for instance, of our rhythmic sense based on negro music would show a complete lack of rhythmic ability among us. Nevertheless, the rhythm of the music of the sixteenth century shows that at that time the rhythmic sense of the average white person was highly developed. There is little doubt that the loss is due to the rhythmic simplicity which developed with polyphonic singing and accompaniment. It is reviving again under the influence of modern jazz.[4]

We may introduce our discussion of differences in psychological performance by the table from Thorndike on page 181.[5] It presents data for but three individuals, but it shows variability in differing amounts in a wide range of traits and abilities. In items I, II, III, and XII the measurements are objective and impersonal. Measures VII and XI are based on distinctively subjective or personal judgments. The others range between these extremes. We see at once how difficult it is to be absolutely certain that our measures of some psychological traits are perfectly objective. Certainly social-cultural experience will affect the direction of variability in some of these matters.


Table 5: Showing Measurements of Three Individuals, A, B, and C
I. Stature 160 cm. 140 cm. 130 cm.
II. Simple reaction— time to sound .175 sec. .125 sec. .150 sec.
III. Average error in drawing a line to equal a l00 mm. line 3.2 mm. 2.8 mm. 2.2 mm.
IV. Number of words (of a list of 12, heard at a rate of 1 per second) remembered long enough to write them immediately after the last word was read 6 words 9 words 7 words
V. Number of examples in addition (each of 10 numbers, repeating no number in any one example, taken at random from the numbers 10 to 99) done correctly in 8 minutes 14 12 18
VI. Quality, or merit, or goodness of handwriting  VII. School marks in history  . . . Ex. . . .Good . . .Poor
VIII. School marks in spelling. 82 62 93
IX. Efficiency in perception; the number of A's marked in 60 seconds on a sheet containing 100 A's mixed with 400 other capital letters . 48 A's 60 A's 82 A's
X. Criminality: number of times convicted of a penal offense 0 1 0
XI. Degree of interest in music little moderate a great deal
XII. Age in days 5,080 6,150 5,615

1. Differences in Mental Imagery —  There are decide differences among people both as to type and as to intensity of images. Our images follow our sensations, which, in turn, rest upon receptor organs. Our

(182) images, therefore, may be visual, auditory, kinesthetic, tactile, gustatory, or olfactory. Within these different types there are marked variations in intensity and persistence of images. The visual type of imagery is said to be the most common. We see the past and conjure up the future in what we call "the mind's eye." Painters, sculptors, and architects are likely to be good visualizers, but Galton reports in his Inquiries into Human Faculty that he found some artists who were not of the visual type. Moreover, persons who have keen visual perception do not necessarily revive their experiences in visual terms. James makes this personal comment in one of his footnotes:

I am myself a good draughtsman, and have a very lively interest in pictures, statues, architecture and decoration, and a keen sensibility to artistic effects. But I am an extremely poor visualizer, and find myself often unable to reproduce in my mind's eye pictures which I have most carefully examined [6]

Furthermore, it appears that as people shift to more and more abstract types of associative thinking their visual imagery declines. Their imagery appears to change toward the vocal-motor or speech type.

The auditory type is less common than the visual. Still some persons have remarkably keen auditory imagery. These individuals actually hear the sound of the words or tones. This seems particularly true of musicians. Beethoven wrote a number of his best-known symphonies even after he had lost his hearing. With his auditory imagery still intact, he could continue to compose music. The playwright Legouvé remarked to his contemporary and fellow-playwright Scribe:

"When I write a scene, I hear, but you see. In each phrase which I write, the voice of the person who is speaking strikes my ear . . . ." "Nothing more correct," said Scribe. "Do you know where I am when I write a piece? In the middle of the parterre." [7]

Kinesthetic or motor imagery is made up largely of images of movement. In feet, as Titchener remarks, "kinesthetic images are extremely difficult to distinguish from kinesthetic sensations." Eye arid head movements. play an important part in the recalling of objects. But for our study the most

(183) common form of kinesthetic imagery is found in the field of verbal imagery, where there is a distinct tendency to form the very words themselves in one's throat. The vocal-motor imagery is particularly important in anticipatory responses.

Other types of imagery— tactile, olfactory, and gustatory— are less common and have a less important place. However, disgust may be roused by olfactory and gustatory images in some people, just as the verbal substitutes (words) for the actual experiences with odors and tastes may arouse either pleasant or unpleasant reactions.

There are probably no pure types of imagery. The content of images is drawn from the various sensory experiences and is recalled in various forms. A person may be a strong visualizer for certain types of experiences and a poor one in others. Again, there are various mixtures of types: visual-motor, visual-auditory, or auditory-motor.

A number of quantitative studies have been made of individual differences in imagery. Cattell and Farrand, using a modification of Galton's questionnaire, found the following differences, among others, in a group of 95 college students:

In answer to the question, "Can you call to mind better the face or the voice of a friend?" 75 per cent answered "face," 14.6 per cent answered voice, 10.4 per cent gave miscellaneous replies. To another question: "When `violin' is suggested, do you first think of the appearance of the instrument or the sounds made when it is played?" 76.8 per cent answered "appearance," 23.2 per cent, "sounds." [8]

Betts' study of mental imagery showed, however, that:

Ability in voluntary imagery is distributed much more evenly among the different types of images than has been commonly thought . . . . Further, so far as voluntary imagery is concerned, visual images cannot claim the supremacy often ascribed to them [9]

Although people may be able to call up images in most of the sense departments, it seems clear that most of us use visual, auditory, and vocal. motor imagery, together or separately, in most of our imaginary activities.

Individual deviations in imagery reveal variation in the manner in which

(184) people revamp their experiences in recall. Since content of anticipatory behavior is an important concern for the social psychologists, it would be worth while to discover whether content of the anticipatory system of the individual is made up of visual, auditory, or kinesthetic, especially vocal-motor, materials. For example, the appeal of personal leaders and of persuaders, like the printed word, might well be modified in terms of differences in types of imagery and their persistence and accuracy.

2. Differences in Intelligence.There is tremendous individual variation in intelligence as in other traits of personality. It seems clear that intelligence differences rest in part upon hereditary factors. The relative constancy of the intelligence quotient, the existence of dull-mindedness and feeblemindedness in the same families for generations, the divergences in learning capacity revealed in a number of investigations, all seem to indicate the importance of heredity. On the other hand, lack of opportunity for education and leisure time, emotional conditioning, and other factors also influence intellectual growth and set certain limitations upon it. Laying aside the controversy, over which so much ink has been spilled, as to the relative importance of heredity or environment in producing these variations, let us see how these differences appear in a society such as our own, in terms of standardized intelligence tests.

Kuhlman has shown that there are variations among very young infants in their capacity to follow a light with the eyes and to differentiate between various sensory stimuli. By the time the child reaches the age of two, it is possible for us to carry on rather satisfactory tests of his intellectual capacity. The table on page 185 shows the individual differences of 100 two-year-old children, fifty girls and fifty boys on the Kuhlman-Binet Tests for Children of Pre-School Age.[10]

These figures show at once that some children even at two years are distinctly ahead of others. Ten per cent of the children are nine months or more advanced over their chronological age, while 26 per cent are six months or more retarded. Already we note from this that some children have an advantage over others in mastering the habits and skills involving, at least, material similar to that in the test. Like differences are found over and over again in other investigations. Baldwin had extensive tests made on children ranging from two to six years of age, and in every type

( 185)

Table 6: Showing Mental Ages of l00 Two-Year-Old Children
Mental Ages No. of Cases
Years and Months
3-0 —  3-2 1
2-9 —  2-11 9
2-6 —  2-8 9
2-3 —  2-5 15
2-0 —  2-2 26
1-9 —  1-11 14
1-6 —  1-8 23
1-3 —  1-5 3
Total 100

of test, of which there were at least thirty-two, he found marked individual variations. For instance, among forty three-year-olds he found that the average intelligence quotient was 112, but that the range for this group was from 84 to 156; among twenty four-years-olds, the average I. Q. was 114, with a range from 79 to 141; among twenty-eight five-year-olds, the average I. Q. was 120, with a range from 86 to 154.

Another illustration: Figure 5 gives graphically the distribution of in-

Histogram showing scores on Army Alpha Intelligence Test of 313 Twelve-year Old Boys and Girls

(186) -telligence scores on Army Alpha test of over three hundred twelve-year-old children of North European ancestry in one public school system. The differences are significant, because all of the children were, at the most, within less than a year of each other in chronological age, but their intelligence, as measured by the test, spreads from dull-normal to a degree of brightness much better than the median grade for enlisted men in the World War. Some individuals in this group were still in the first and second grade, a considerable number in the third and fourth grades. The majority were in the fifth and sixth grades. There were some in the eighth grade, and among these were a few quite capable of doing high school work of first-rate quality.

During the World War the military administration, in connection with psychologists, worked out a rating scale, based on group intelligence tests, in order to estimate the military fitness of the men in the army. The rating scale consisted of the following letters with accompanying interpretations:

A Very superior: high officer type.
B Superior: commissioned officer and splendid sergeant material.
C+ High average: Good non-commissioned officer material.
C Average: Good private material.
C- Low average: ordinary private.
D Inferior: largely illiterate or foreign. Slow learners.
D- Very inferior: but fit for service.
E Mental inferiority of such grade as to warrant special service organizations or discharge.

Figure 6 on page 187 shows the distribution of these ratings in typical army groups. It reveals the marked individual differences among men in the army, and in a way it indicates what is largely true of peace-time populations. Other studies have shown a correlation of intelligence variability with differences in occupation. The unskilled and semi-skilled tend to have the lowest scores, the skilled trades and clerical. the middle scores, and executives, professional, and other leaders the highest scores. There is no doubt but that individual differences have much to do with social status and success in life adjustments. Figure 7 on page 188 reveals differences and overlapping of scores in various occupations.


Figure 6. Showing Distribution of Men in Various Army Groups as Measured by Intelligence Tests

3. Differences in Emotional Reactions.— There has been little systematic work on individual variability in emotions. Certainly no one has studied child behavior with sufficient thoroughness to be able to describe such differences in adequate statistics. Clinical observations, however, expose the existence of variability even if there are no statistical criteria for determining the amounts of these differences for unselected groups of cases. Differences in endocrine balance, for one thing, make for evident variability in emotional expression. Observations on children show that some respond to loud sounds more quickly than others, some show irritation and rage more easily, and so on. It is evident that social conditioning very soon begins to determine, in part, the direction which emotional expression takes. The following instance from a baby clinic shows such a shift:

In the first day of life this infant cried at every new pronounced stimulusas soon as he was picked up he cried; he ceased to cry when allowed to lie quiet. In two weeks his social environment induccd a complete reversal of this relation between stimulus and response. He cried while he was in the crib; he ceased to cry when picked up.[13]


Figure 7 Showing Distribution of Intelligence in Relation to Occupation Difference, median and overlapping are shown

If this change can occur in a fortnight, one naturally asks what changes may ensue in emotional expression in a few months, and in subsequent years? Thus we are at once confronted with the whole problem of the social conditioning of emotional reactions. Such conditioning affects variabil-

(189) -ity, which, in turn, must greatly alter social interaction. We shall discuss in the next section the place which individual differences in physique, intellect, and emotion occupy in social behavior. Aside from possible deviations in strength of fear, anger, or love responses at the outset, based on differences in physiological structures and functions, it is clear that by the time children come into contact with other children emotional variations are very evident. The observations of Mary Cover Jones on children's fears indicates individual differences in emotions, dependent largely upon social conditioning:

Case 41: Arthur G. Age 4 years: Arthur was shown the frogs in an aquarium, no other children being present. He cried, and said, "they bite," and ran out of the play-pen. Later, however, he was brought into the room with four other boys; he swaggered up to the aquarium, pressing ahead of the others who were with him. When one of his companions picked up a frog and turned to him with it, he screamed and fled; at this he was chased and made fun of, but with naturally no lessening of the fear on this particular occasion.

Case 8: Bobby G. Age 30 months: Bobby was playing in the pen with Mary and Laurel. The rabbit was introduced in a basket. Bobby cried, "No, no," and motioned for the experimenter to remove it. The two girls, however, ran up readily enough, looked in at the rabbit and talked excitedly. Bobby became promptly interested, said, "What? Me see," and ran forward, his curiosity and assertiveness in the social situation overmastering other impulses.[15]

These observations indicate at once that emotional responses are built up around specific situations by the process of conditioning. They show, moreover, that variations in emotions, as in intelligence, depend in part at least upon the nature of the situation and the nature of the responses that have been built up toward it. The presence of other persons makes for divergences in response. A child alone in the presence of a barking dog may show fear. A child in the arms of a mother before a barking dog may show other responses. The situation in one case is certainly not like that in the other. Being in the mother's arms is as much a part of the stimulating situation as the dog itself.

D. Physical Differences and Divergent Personality Traits.

Efforts have long been made to correlate physical variations with mental, emotional, and temperamental deviations. On the basis of common-sense

(190) observation people have recognized certain differences in personality trends as correlated with differences in physique. Shakespeare puts into the mouth of Caesar a remark about Cassius:

Let me have men about me that are fat;
Sleek-headed men, and such as sleep o'nights:
Yon Cassius has a lean and hungry look;
He thinks too much: such men are dangerous.

The slender, sober Cassius represents an intellectual type as against the fat, round, jolly Falstaff sort, who is more concerned with his physical pleasures than with political philosophy and power. It was Lombroso, in modern times, who gave the greatest emphasis to the notion that types of behavior were correlated with physical characteristics. His theory of the causes of crime stated that about 40 per cent of criminals were born such, and that one could recognize them by certain anomalies or marks of degeneration, such as asymmetrical head form, low forehead, projection of the ear, flattened nose, and so on. The brilliant researches of Goring in England proved that criminals possessed no more stigmata of criminality than did the "law-abiding public" at large. Again, there has been considerable popular superstitution that low intelligence is accompanied by physical abnormalities of various sorts. Pintner, Anderson, and others have shown that judgments of intelligence, based on photographs, even by persons familiar with the feebleminded, show no correlation with actual measurements of intelligence.

Numerous studies have been made to discover any possible correlation of certain morphologic characteristics and intelligence measurements. Naccarti and Guinzberg found some correlation between intelligence and the ratio of height to weight, holding that tall, thin persons were somewhat more likely to rate higher in an intelligence test than short, stout persons. Yet Heidbreder's study of height-weight ratios and scores on intelligence tests among a thousand college students failed to reveal any significant correlation between body build and intelligence. Sheldon found some slight relationship between certain bodily measurements and mental ability, i. e., his statistics indicate that within certain broad limits tall, slender men are slightly superior to short, fat men in intelligence.

Over a generation ago Kraepelin, a German psychiatrist, made a basic differentiation between two types of psychoses: the manic-depressive and

(191) the dementia praecox. The former, which is also called the circular or cyclic type, runs to alternating moods of depression or mania. One finds such patients lapsing into intense depressions to be followed by manic, hyperexcitable states, and various combinations of mania or depression with more normal behavior. With this type there seems to be little permanent mental deterioration, on the whole, but rather fairly temporary periods of disorder, followed by quite normal social reactions. In the dementia praecox or schizophrenic type, to use Bleuler's term, the disorientation of mind and behavior is much more insidious in its inception and much more permanent. The disease is marked by regression from social reality. The individual loses contact with his fellows. At the outset his disorder may become apparent by his development of carelessness in dress, manners, food habits, and bodily care. Mentally there is a distinct tendency toward introspection, to the building up of fantasies of one's own, and finally, in the more extreme cases, rather complete severance of relations with the normal social world.

Subsequent clinical observations and some recent experimentation have led to the belief that these two types of mental disorder represent in more divergent form fundamental differences in human personalities. Kretschmer took up the problem of attempting to discover if there was possibly some physical correlation with these types of personality. Taking his cases among patients largely of Swabian ancestry, he made extensive measurements of physical form. From his investigations he found three more or less distinct types, with certain overlapping among them, as one might expect. The types are not absolutely distinct from each other, but rather approximations to types through statistical averages. The first of these types is the asthenic; the second, the athletic; the third, the pyknic. The first is characterized, as a rule, by the lean, narrowly-built man, with poor blood, poor skin secretion, narrow shoulders, long, thin arms with thin muscles, delicately boned hands, long, narrow chest, thin stomach, and the lower limbs built on lines similar to the upper. The face is of the angular sort. There are some variations, but these are the most noticeable features. The second type is marked by strong development of the skeletal framework anti the muscles. The skin is firm and healthy. The shoulders are broad, the chest thick, the abdomen well covered with layers of muscle, the trunk tapers toward the middle region, the pelvis is narrow, and the legs are tapering and shapely. The arms are heavily muscled. The face is firm, the jaw prominent,

( 192) the nose tends to be shorter and more snub-like. The third type, which according to Kretschmer reaches its highest development in middle age, is characterized by pronounced development of the rounded figure, fat about the trunk, a deep vaulted chest which broadens out toward the lower part of the body. The limbs are soft and round and display little muscle relief, as do those of the second type. The shoulders are usually rounded and pushed slightly forward.

According to Kretschmer, these types do not appear in pure form, necessarily, but are sometimes mixed with others. So, too, he classifies some of his cases as dysplastic, that is, marked by distinct asymmetry of organs.

On the basis of his measurements of nearly four hundred cases of manicdepressives or cyclothymes and of dementia praecox patients or schizophrenics, he worked out a correlation of the two types of temperament with the three types of physique. On the one hand, he found a correlation between the asthenic and athletic types and schizophrenics arid, on the other, between the pyknic types and the manic-depressives.

So far, no thorough check-up of the Kretschmer types has been made upon normal populations. Mohr and Gundlach made a study of American-born prisoners at Joliet, Illinois, in an effort to verify Kretschmer's classification. Using first clinical observations and later exact physical measurements, they attempted to classify the men in terms of Kraepelin's two types of personality on the basis of tests. Instead of two or. three sharply-defined types, they found rather a gradation from one group to another in physical make-up. In their conclusions they remark:

Our results support in a general way the Kretschmer theory of physical and temperamental kinds, in that a relationship between physique and character of performance is demonstrated. They tend to modify the theory, however, by breaking down even Kretschmer's loose conception of "types" and insisting on the concept of a general progression both of performance and of physical characteristics.[16]

The validity of the concept of "type" is involved in all problems of personality differences. At best, perhaps, these may be thought of as average statistical deviations from measurements, both physical and psychological, which are distributed over a common scale. Therefore we may, with-

(193) out accepting as final Kretschmer's correlations, recognize in these studies another feature of individual differences which have a bearing upon social behavior. We may imagine personalities arranged along a scale. At one end are the schizophrenics, who are introverted, tender-minded, romantic, and rather infantile in many characteristics. At the opposite end are the cyclothymes, or manic-depressives, who, in contrast, tend to extroversion, to be tough-minded, non-romantic, and distinctly interested in and controlled by the external material and social reality around them. Perhaps the differences, especially toward the extremes of this scale, are such that we are justified in defining them as "types," doubtless with the bulk of the population lying somewhere in the middle range.

As cyclothymics Kretschmer classified realistic and humorous poets, descriptive experimental scientists, and those executives and leaders whom he called "tough whole-hoggers," "jolly organizers" and "understanding conciliators." As schizophrenics, he put formalistic and romantic poets, exact logicians and systematic metaphysicians, and those executives and leaders whom he termed "pure idealists," "despots and fanatics," and "cold calculators."

Other attempts have been made to link up morphologic traits with social characteristics. Sheldon found slight but positive correlations between certain social traits, determined on a rating scale, and certain physical characteristics. Of the sixty correlations computed, twelve are above 0.10; only two above 0.20; eighteen are negative, but with one exception low. The following quotations from this writer's study give some of the more significant findings:

Sociability shows a negative correlation (-0.217) with morphological index, and a positive one with weight (0.131). This seems to support to some slight extent the popular notion that fat or "heavy-set" men are more sociable than thin men. Yet there is no correlation higher than 0.09 between sociability and any single physical measurement. Whatever relation exists here is certainly not due to the preponderance of any particular part of the anatomy over the rest.

The trait aggressiveness shows the greatest number of relatively high correlations with the physical measurements . . . . The correlation of 0.240 between this trait and transverse epigastric diameter is the highest in the entire group . . . . Aggressiveness appears to go with bigness of frame rather than with any special morphologic trait . . . . Weight apparently is less a factor here than general bigness of stature. There seems to be some slight evidence that

( 194)macrosplanchnics [related to Kretschmer's pyknic type] are more aggressive than microsplanchnics [like the asthenics].

In the column headed Leadership three correlations are over 0.10. . . . . . The large-bodied fellows (macrosplanchnics) are somewhat higher in both sociability and leadership, apparently to about the same degree that they are lower in scholarship and intelligence . . . .

Emotionality correlates uniformly low with almost all of these measurements.... It is of interest to note that the three traits, leadership, aggressiveness, and emotionality show uniformly positive correlations with all the measurements, and all three correlate negatively with the morphologic index. Evidently these traits are associated slightly with general bigness of body, and also to some slight extent with compactness, or preponderance of the torso over the extremities. Perseverance shows almost the opposite tendency.

Eight of the twelve correlations between Perseverance and physical measurements are negative, but they are very low [17]

While these figures do not give variability within the group, and while the correlations are low and made on only twenty-eight cases, they' do reveal some slight relationship of physique to social traits as measured by ratings of others. In considering leadership, aggressiveness, sociability, emotionality, and perseverance, as rated on a scale at least, one must take into account individual variation in physical characteristics.

E. Social Behavior and Individual Variability.

Again we must emphasize the fact that the variations which we have been noting do not rest upon hereditary bases alone. Nutrition, endocrine balance, practice, and social experience all play a part. We noted that height and weight of populations varied with food supply. There are differences in physical and mental maturation correlated with economic and social status. Certainly cultural deviations and personal-social experiences have much to do with individual differences. On the other hand, in many ways these conditioning factors make for likenesses as well. For instance, violin playing may be engaged in by persons with variations in morphology of hands and arms, and yet the listeners at a concert may not be aware of these differences. So, too, social groups demand conformity to certain codes of behavior, certain definitions of situations, in spite of divergences in physical, mental, and emotional traits. Thus, while individual variability is highly significant, the direction which individual life organization

(195) takes is largely determined by cultural norms and personal-social experience and not alone by these more strictly biologic factors. To reassert our fundamental standpoint, in unraveling the factors in any individual's behavior we must at all times take into account his biological, psychological, and cultural backgrounds. No one of these alone is sufficient to account for behavior.

In spite of certain behavior patterns common to various groups, cultural and personal-social conditioning produces divergences which we shall have occasion to note further on. Here we shall indicate these influences only in broad outline.

1. Conditioning and Deviations.— The new-born child is thrown by circumstances at once into a world in which he is the weakest and most dependent member. The whole period of infancy may be one in which the child takes a position of inferiority. Physically he is at the mercy, more or less, of parents, of older and stronger brothers and sisters, and later of playmates. Then, too, his native talents may be bent into patterns which fit the family code, as when a boy of artistic tastes may have to forego their development in order to help support the family by ordinary labor. Or a boy may be apprenticed to a skilled trade when under other circumstances he might well have become an inventor. Then, too, rivalry in the family may give rise to the development of certain traits, such as aggressiveness or docility, out of the very relationship of a child to his parents and his siblings. For example, the first boy of a family may acquire dominant attitudes because the parents favor the younger brother or sister. His aggression is developed as a means of getting attention. Adler has shown how potent these influences are. Therefore, one raises the question whether dominance or aggressiveness and the degree of its intensity are really matters of inherited differences, as experimental psychologists sometimes assume, or a development based upon social or cultural conditioning.

If the family belongs to a certain social class, the child is compressed into the types of action and attitude of that class, no matter if he may wish otherwise. The boy who might he shy and retiring may assume the position of superiority demanded by the social status of his family. Too frequently writers, past and present, have assumed that attitudes of dominance and the assumption of rôles of social leadership rest really upon innate ability, when actually these may depend in large part upon economic and social status of the class, coupled with the culture pattern of ascend-

( 196) -ency. It is curious, as Michels, Pareto, and others have pointed out, that the upper classes or the élite everywhere tend to take on certain formal leadership characteristics. This is neatly seen in the rise of the poor immigrant family in our own country to a position of opulence or political power. When a person arrives at these social positions later, he, and especially his children, soon take on the distinctions of their class and before long the marks of peasant and "common" origin are left behind. The nouveau riche always assume the letters patent of the classes which they aspire to reach.

One of the most profound factors in determining individual differences in society is occupational choice. Further on we shall point out some of the effects of occupation upon social attitudes, but at this point it is sufficient to note that the vocation which a person has to take or which he chooses will make a vast difference in his relations to his fellows. The division of labor in modern society sets up frames of occupation which make for significant divergences in the personality.

At the outset differences in learning capacity will give one boy great advantages over another in mastery of school subjects, in learning to take care of himself in a group and to acquire the social and moral codes which make adjustment to his fellows more easy. By the time they reach adulthood some people are found in highly skilled and technical professions, a mass in the middle range of small business or skilled trades, and the rest at the bottom as semi-skilled and unskilled laborers. The variations are evident to all, and whether the distributions revealed by the paper and pencil tests of the psychologists give the exact picture is beside the point. The significant fact is that individual variability is correlated in the social order with division of labor.

Not only does capacity to learn determine the direction of one's place in this scheme of division of labor, but cultural patterns also play a part. Class lines determine that the sons of professional men shall go, on the whole, into professions. The boys of railroad engineers tend to be apprenticed to their father's work. Not only do differences in learning ability and the cultural norms of the group fix the division of labor, but the personal-social experience of the individual may assist in the process. For instance, the sense of inferiority of the eldest son in a family developed from being given less place than the younger children, may set up in him such negative reactions that the suggestions of his father or mother about a certain

( 197) profession or occupation may meet with resistance. In order to offset this authority he may take to some other vocation. In this way he retaliates for the manner in which his parents treated him. Again, a doting mother may project on her son some vocation for which he is not particularly well fitted, and yet by dint of practice he may attain mediocre success. Here the mother-son relation— a socio-personal experience— determines the direction of life organization and the individual's place in the scheme of the division of labor.

A case of the effects of different opportunity in relation to occupation is illustrated in the immigrant family where the older boys, due to economic stress, are forced into common and semi-skilled labor, but when the economic status of the family improves, the younger members of the family get a better education and go into business or the professions. If this is not possible within one generation, something similar takes place in the occupational differences between the first and second generations. If the cultural lag is great, it may require three or more generations for the shift to take place. Throughout all this the opportunity for education, such as schools, general community or group approval of intellectual and vocational betterment, must be considered. Another example of the effect of occupation on individual differences is seen in the generally known fact that a considerable number of European immigrants to our country have to give up their old world occupations, often skilled trades or even technical professions, and take up common or semi-skilled work here in order to make a living. Bloch reports:

Taking these sixteen skilled occupations [given in his tables from U. S. reports], only 23.7 per cent of those who came to the United States and did not return took up their former occupations; 76.3 per cent scrapped their skill and experience and took up some other trade.[18]

This would give a re-shifting of individual variability in society which might quite belie the original intellectual capacity of the persons concerned. So, inn, financial reverses may reduce a family from one social class to another, producing another realignment of individual functioning in the social group. This is witnessed in class changes which have taken place in post-war Europe, especially in Germany and Austria. Many

(198) families formerly of aristocratic or upper middle-class status have been reduced to the lower economic levels. On the other hand, former petty bourgeois families have risen in social rank through financial success.

Similar differences in social function are evident in the religious and political life of individuals. Participation in the church group of one's family may lead to the development of habits of attendance at church or Sunday school, or it may lead one into becoming a Sunday school teacher. In contrast, membership in another church might not lead to a social function of this sort at all. This matter is exactly illustrated in the Mormon church, where there are no paid ministers. Here the differentiation in function in the religious group goes very far, because in terms of capacity, education, interest, and the social prestige of certain prominent families, a man or woman may come to assume a position of leadership which in other church groups the lay member might never gain.

Again, out of religious training, differences in world view and the meaning of life may stretch over wide areas. No matter how alike in physique, in emotional-instinctive tendencies, and in native learning capacity two brothers may be, if one were raised a Catholic and one a Baptist, each would be bound to develop attitudes reflecting his religious training, and the differences in life philosophy could be fully interpreted only in terms of their divergent social and cultural backgrounds. Even identical twins, as Freeman has shown, develop into distinctly different personalities when reared in divergent families and varied cultural milieu. In the larger scope of philosophic viewpoints the Christian might develop notions of freedom of the will, whereas the child raised in the agnostic and scientifically trained family might reasonably be expected to take on a world view of determinism and even a kind of fatalism. The differences in ethos rest really upon just these variations in the individuals, which, in turn, go back largely to divergent culture patterns.

Similar comment may be made in regard to political differences in people. These may have little or no relation, for example, to deviations in native learning ability, but rather depend upon similar social cultural patterns from respective political camps, Democratic, Republican, or Socialist, or in certain European countries, Royalist or Monarchist as against Republican or Communist.

The upshot of the matter is that social-cultural patterns inflict upon us forms of individual differences other than those determined by biological

( 199) forces. There is, no doubt, some correlation between intelligence and scholarship, and between intelligence and business success, but the differences are not at all determined by something inherent. In fact, even with the highly unreliable intelligence tests, which rest so much on cultural factors, the positive correlation with occupation is hardly better than 0.30 and usually less. The statistical reliability of these figures is extremely low. Individual variations are everywhere evident in society, and some of these differences rest rather distinctly on biological divergence s —  divergences in capacity, physical, emotional-instinctive, or intellectual. Other deviations arise out of personal-social experience. Still others are laid down by the cultural patterns. Once more we must be careful not to fall into the particularistic fallacy and try to interpret such phenomena as individual variability in terms of one dimension only, but always recall the three factors: the biological-psychological roots, personal-social experience, and the stimulation through cultural patterns. These factors must be examined before the full picture can be exposed and certainly before one may venture a guess as to which of these produced the difference or which, if all of the factors contributed together, contributed most.


A. Further Reading: Source Book for Social Psychology, Chapter VI, Section A, pp. 121-39

B. Questions and Exercises.

1. Discuss questions and exercises in assignment in Source Book, Chapter VI, p. 143, nos. 1-6.

2. What factors produce individual differences (a) in physical traits, (b) in intellectual traits, (c) in emotional traits?

3. Discuss, pro and con, the weight to be given "original nature" and "nurture" (personal-social and cultural influences) in producing the personality. Do we gain anything by attempting to fix definitely the weight of each set of influences? (Cf. Child's paper, Source Book, no. 55, pp. 194-206, and the discussion above, Chapter III, pp. 35-40.

4. (a) In which dimensions of adult personality are "original" factors more dominant, (h) in which, factors called "nurture",

5. Illustrate how cultural norms may override individual differences.

C. Topics for Class Reports and Longer Written Papers.

1. See assignments for reports and longer papers in Source Book, Chapter VI, p. 144.

2. Report on Thomas, Child in America, Chapter XI, on recent studies showing relation of physical-traits to personality.



  1. H. O. Rugg, Statistical Methods Applied to Education, 1917, p. 168. Used by, permission of, and by arrangement with, Houghton Mifflin Company.
  2. Quoted by H. Woodrow, Brightness and Dullness in Children, 1919, p. 100. Courtesy of Lippincott & Company.
  3. Ibid., p. 111.
  4. F. Boas, "Growth and Development, Bodily and Mental, as Determined by Heredity and by Social Environment," in the symposium, The Child, the Clinic and the Court, 1925, p. 186. Courtesy of New Republic Company.
  5. Modified slightly from E. L. Thorndike, Educational Psychology, 1914, vol. III, p. 155. Handwriting judgments by examination of samples of writing omitted. Courtesy of Bureau of Publications, Teachers College, Columbia University.
  6. W. James, Principles of Psychology, 1890, vol. II, p. 53. Courtesy of Henry Holt and Company.
  7. Cited by A. Binet in The Psychology of Reasoning, 1912, p. 22-23. Courtesy of Open Court Company.
  8. Cf. J. McK. Cattell and L. Farrand "Physical and Mental Measurements of the Students of Columbia University," Psychological Review, 1896; vol. III, p. 646.
  9. G. H. Betts, "The Distribution and Functions of Mental Imagery," Teachers College, Columbia University, Contributions to Education, No. 26, 1909, p. 45.
  10. From F. L. Goodenough, The Kuhlman-Binet Tests for Children of Pre-School Age, 1928, p. 38. Courtesy of University of Minnesota Press.
  11. From K. Young. Mental Differences in Certain Immigrant Groups. 1922.
  12. From Army Mental Tests (pamphlet), 1918, p. 8.
  13. A. Gesell, The Mental Growth of the Pre-School Child, p. 201. Copyright 1926 by the Macmillan Company. Reprinted by permission.
  14. Ibid., p. 23.
  15. Mary C. Jones, "The Elimination of Children's Fears," Journal of Experimental Psychology 1924; vol. VIII, pp. 387, 389.
  16. G. J. Mohr and R. H. Gundlach, "The Relation Between Physique and Performance," Journal of Experimental Psychology, 1927, vol. X, p. 157.
  17. W. H. Sheldon, "Social Traits and Morphologic Types," The Personnel Journal, 1927, vol. VI, pp. 51-53.
  18. L. Bloch "Occupations of Immigrants Before and After Coming to the United States:" Quarterly Publication of American Statistical Association, 1920-21, vol. XVII, p. 760.

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