The relative importance of nature vs. Nurture has been investigated by different psychologist sociologist. The conclusion of their studies reveals that the intelligence is the product of heridity & environment.
i)Distribution of Intelligence : It resembles the distribution of health, wealth, beauty and similar other characterstics. Its a normal distribution that is governed by a principle the majority of the people are at the average, a few very brillant and a few very dull.
ii)Individual difference in Intelligence : Individual different is existed between person to person, even the identical twin or the individual nurtured almost in similar environment doesnt have equal mental capability following in them. Thus it states that intelligence varies from person to person even in same individual from age ton age & situation to situation.
iii)Intelligence and change in age : After the vertical growth in intelligence it reaches at maximum at the age of 16-20 in individual. But the horizental growth(accumulation of knowledge and aquisition of skill) continues throughout the life span of an individual.
iv)Intelligence & Sex difference : Various studies have been conducted that women are less intelligent than men. The result of result hang in one way to another. Thus the sexual differentiation doesnt contribute towards difference in intelligence.
v)Intelligence and racial & cultural difference : Various hypothesis and research have been examined wether a particular race, caste or cultural group is superior to another in intelligence. The bright or dull can be find in any cultural group, race or caste and the diference which are found can be explained in term of environmental influence.