Assisgnment 9

Child Psychology Diploma Course
Assignment Nine.

How much of a child's intellegence is genetically determined, inherited from his/her parents, and how much is due to his/her environment?  
Hebb proposed a theory which tried to acknowledge the influence of both hereditary and environmental influences.   He proposed the notion of intellegence A and intelligence B: Intelligence A refers to the individual's potential intelligence.   This is the genetically determined upper limit which the person could attain.   Intelligence B refers to the extent to which this genetic potential is actually realised as a result of the individual's experience in his environment.
To these Vernon added Intelligence C.   Since intelligence tests can only hope to sample part of a person's total level of Intelligence B; Intelligence C is this unknown proportion of intelligence which is measured in an intelligence test.
This view is very much the half-way view between the two extremes.   There are theorists who hold much more extreme and rigid views. e.g. the extreme nativist viewpoint suggests that all intelligence is inherited.   Thus, those people who have low intelligence will only ever produce offspring of low intelligence.   It's clear to see the way that this belief can ultimately lead.   Nazi beliefs were based on just this type of extreme theory.
Correlations between IQs
Although few formal studies have attempted to prove that all of an individual's intellectual ability is inherited, various studies have attempted to place a figure on the amount which is genetically determine and the amount which is due to the environment.   One particular research method has been used to try to assess just these amounts.   This is by studying MONOZYGOTIC   and DIZYGOTIC TWINS both reared together and apart.
MONOZYGOTIC twins are identical twins, developing from a single egg.   Therfore they share an identical genetic structure.   When reared together, they share the same heredity and same environment....