In this article we will discuss about the studies and experiments to ascertain the influence of heredity and environment on human personality.
1. Studies in terms of Class or Occupational Studies:
These studies show “that the groups with the higher social or intellectual ratings have produced more persons of genius or distinction”. One such study shows that in the United States besides the families of the clergy and of professional men, the largest proportion of notable men came from the families of businessmen, farmers and skilled labourers.
Another study calculated that the chances of sons of different occupational groups to gain eminence were as follows: unskilled labourers, 1 in 48,000; skilled labourers, 1 in 30; farmers 1 in 70; businessmen, 1 in 600, etc.
These studies indicate a superficial analysis of the problem of heredity and environment. What these studies simply indicate is that the sons born in ‘higher’ classes or occupational groups have a greater chance to develop intellectual or other attainments. These studies do not tell us anything directly about heredity and environment.
The persons who conducted these studies came to the conclusion, on the basis of their findings, that heredity was a more potent factor than environment. But one may use the same findings to establish exactly the opposite conclusion, namely, the relative importance of environment as compared to heredity.
It may be argued, and not quire unjustifiably, that each social or occupational class has its own distinctive environment.
The differences in attainments as between sons of different groups may very well be ascribed to differences in environment. The case for heredity can only be established if we can successfully discount the effect of environment.
Secondly, the explanation of these differences in terms of heredity alone is based on the implicit assumption that “the distribution of occupational groups represents the inevitable assortment of the population into levels of ‘natural ability”.
Such an assumption cannot, however, be made because “the occupational distribution of people is a complex social phenomenon, not basically determined by or measured by the biological or any other single factor”.
2. Studies Based on Intelligence Tests:
Some writers tried to establish the relative importance of heredity by applying ‘Intelligence Tests’ upon different groups of people. They concluded on the basis of their findings that some races are mentally superior to others.
In their opinion, the average score of the Negroes is lower than that of the Whites because the Negroes have inherited the mental deficiency of their forefathers, and the Whites the mental excellence of their ancestors. That is, their contention is that mentality is a product of one’s heredity.
These studies suffer from certain defects. In the first place, some writers question the assumption that ‘Intelligence Tests’, which involve “degrees of facility in performing particular operations under particular conditions”, measure faithfully the general intelligence of those who are subjected to these tests.
These tests “are to a considerable degree simply knowledge tests scored relatively to the achievement of like-age children”.
Secondly, these tests do not eliminate the factor of differential environment, such as differences in home life, in training facilities and in social opportunities. The Negroes come off worse in these tests as compared to the Whites because of differential environment.
That this conclusion is true is corroborated by the findings that in the U.S.A. “Negroes educated in the North do much better on the tests than those in the South”. In the absence of similar environmental conditions “intelligence tests are measures of accomplishment but not of innate racial differences in mental ability”.
3. Studies of Selected Families:
Some sociologists have studied selected family groups as evidences of good and poor heredity. We may consider here two such family groups—the Jukes and the Edwards. One Mr. Juke was born in New York in 1720. In 1877, 1200 of his descendants were identified.
Of these 400 were found to be physically defective or diseased, 310 paupers, and 300 had died in infirmaries. Another 130 had been convicted of crimes; of them 7 were murderers. Perhaps more than half of the women were prostitutes.
A further investigation was made in 1915 which unearthed 2,820 descendants. Of these, 600, then living, were mentally defective. A contrast to this dreary picture is found in the bright record of achievement of the descendants of one Mr. Edwards. In 1900 altogether 1,394 of his descendants were identified.
Of these, 295 were College graduates and many of them distinguished themselves in professions and business. They included 13 College presidents, a Vice- president of the United States, and no convicted criminals. Some find in such striking contrasts the incontestable evidence that heredity is relatively more important than environment.
These conclusions are unacceptable for various reasons. To begin with, every generation is a fresh admixture. Hence, after three or four generations, very little of the past hereditary traits remain. The surname merely indicates their ancestry, and little or nothing about hereditary traits and qualities. Of the two brothers, one may be a person of saintly character and another a convicted criminal.
The son of a genius may be a fool. Does heredity help us in explaining these striking contrasts? Secondly, we cannot ignore the fact that the Jukes had an unfavorable social environment, while the Edwards had a favourable one. Did not environment play an important part in determining their outlook, way of life and accomplishments?
All the studies suffer from the fact that the influences of heredity and environment could not be entirely separated. As a consequence, those who want to discount the influence of heredity may look to one side of the picture and emphasise simply the environmental factors, and those who want to discount the influence of environment may emphasise simply the hereditary factors.
In view of these difficulties, several ‘controlled’ studies have been made. These studies keep one factor constant and make studies of variations of the other factors.
Thus, several studies have been made of:
(a) Identical twins reared together,
(b) Identical twins reared apart, and
(c) Children of different parentage reared together.
None of these studies have, however, been able to disentangle the influences of heredity and environment and ascertain the percentage contributions of each factor in the making of one’s personality.
These studies, on the other hand, “help us to see more fully that we must always reckon with man’s nurture no less than with his nature”. We cannot ignore the fact that the environment of our past as well as the environment of the present are written in our lives. Can we ever measure separately the influence of both?
It is futile, therefore, to pursue the question as to which of the two is more important or more potent.
These studies reveal beyond doubt that both are equally necessary for a given result:
“Neither can ever be eliminated and neither can ever be isolated…. Both have been operative, to produce every particular situation, through unimaginable time. For these reasons it seems impossible ever to conceive two situations involving precisely the same combination of heredity and environmental factors. Every situation is in this respect unique, just as every human face is in some way different from every other”.
Just as it is futile to try to determine as to whether food is more necessary than air for the sustenance of life, so also it is useless to enquire the relative importance of these two factors. Both are necessary for a given result in the same way as both food and air are necessary for life. Every phenomenon of life is the product of both.
A sociologist is interested in the way in which an individual or group reacts to a certain environment, and not in heredity as such which deeply concerns the biologist. A sociologist accepts heredity as given, and enquires which environmental conditions are favourable for the fulfillment of hereditary qualities and which conditions are not.
“Heredity contains all the potentialities of life, but all its actualities are evoked within and under the conditions of environment”. It follows from this that the higher the potentiality, the greater is the demand made on environment.
Instead of seeking to establish the importance of one factor over the other, we should recognize that, “the finer or the greater the heredity, the more does the fitness of the environment matter”.
For instance, a talented student will more keenly feel the absence of an academic atmosphere at home or in an educational institution than a student of average caliber. A very minor change in the environmental situation may mean little or nothing to most of the people, but such a change may be vastly significant to a person of sensitive nature, say, to an artist.
Moreover, we have to take into account the fact that the quality of an environment matters most during the impressionable periods of our lives. It is doubtful if Einstein could grow up into an eminent scientist if he were born in an Indian village with little or no educational facilities. The opportunities available to us in this industrial age have brought to eminence men who would have remained in obscurity in an earlier age.
Psychologists are of the view that it is not possible for anyone to develop and express all his potentialities in full. According to some, not more than then per cent of one’s potentialities can be developed and utilised. In the circumstances, it is worthwhile exploring the conditions which enable a person to make a maximum use of his potentialities.
On this point, Dr. Shaffer’s observations are very pertinent:
“Since it is unlikely that anyone ever attains his full capacity it is important that efforts be directed to a better understanding of the environmental encounters most likely to promote intellectual development”.
Dr. Shaffer further observes:
“There is the strong suggestion that since the change in intellectual structures is most rapid during the child’s early life the early environment encounters are the most important”. We should, however, be careful not to read too much into these examples.
These illustrations indicate simply that favourable environment may give a man of genius the necessary opportunity to reveal his power, and that a person, however talented he might be, will fail to do so in the absence of adequate opportunities. On the other hand, no amount of opportunity would enable a man of mediocre talents to attain the height of a genius. Both heredity and environment are, in fact, essential for our fulfillment. We cannot over-rate one at the cost of the other.