Relative Importance’s of Heredity and Environment are given below:
1. The foregoing discussion reveals that both heredity and environment have their share in moulding the life and personality of the individual. But as regards the extent of their influence opinions differ.
2. Heredity is responsible for all the inborn traits, the instincts, emotions, I.Q., reflex action and physical traits.
3. Environment is responsible for the growth and development of the physical, mental and social traits.
4. The two forces heredity and environment are not opposed to each other, but are complementary like seed and soil, ship and current, ‘warp and woof, bed and stream etc. Both of these forces are required for the same purpose. The heredity is the raw material out of which the object is to be prepared, and environment in the technique and other material for the manufacture.
Environment is nothing but a process under suitable conditions to change the shape of raw material just as potter does while making toys of mud. Human behaviour is the product of heredity and environment. Hence both are equally important. The verdict of T. Percy Nunn is nothing short of final:
“Circumstances of life are to men what rocks and winds, and currents are to a ship; merely accidents that make their qualities manifest but have nothing whatever to do with producing them.”
5. Interaction of Environment and Heredity. Human behaviour is determined by interaction of heredity and environment. The individuality of person is characterised by some inborn traits inherited by the person. The task of the environment is to shape these traits in a proper form, to give opportunities for their unfoldment and fulfillment, and to help making improvements. Thus the personality of the individual is a product of heredity and environment.’
6. Improvement through Environment. Environment can definitely improve upon the behaviour of a person. Increase the environmental situation, improve its quality, even though the heredity remains constant, the behaviour will improve. It was explained above children brought up in nursery and progressive schools or in good foster homes showed improvement in their intellectual calibre after some time. They were better than those who were brought up in ordinary environment but were initially of the same heredity.
Two individuals of the same heredity might differ when put in dissimilar environments. Again two individuals of differing heredity would probably differ inspite of identical environments. So we can predict that if we change either factor, the product is changed. But Algebra alone will not help us in measuring the quantity of improvement. Detailed investigations are needed for that but roughly we can made an estimate of the changes in the behaviour due to change in either of the factors.
Suppose we have got three children of three different grades of heredity viz. superior, average and low (symbolically put as S, A and L). Suppose there are three grades of the environment also (S, A and L). If the child with superior heredity is put in superior environment, his personality will be highly superior because S x S = S. If he is put in average environment his personality will be somewhat superior (S x A = SA). The different combinations are as follows:
(i) Superior heredity and superior environment, S×S = S
(ii) Superior heredity and average environment, S×A = SA
(iii) Average heredity and superior environment, A×S=AS
(iv) Average heredity and average environment, A × A =A
(v) Superior heredity and low environment, S×L = SL
(vi) Low heredity and superior environment, L × S = LS
(vii) Average heredity and low environment, A ×L = AL
(viii) Low heredity and average environment, L×A = LA
(ix) Low heredity and low environment, L×L = L