intelligence

Intelligence is the level of competence, ability to learn or to some people it is how well an individual performs on an IQ test. The structure of intelligence is best subdivided into two significant categories. They are environmental and hereditary influences.

Environmental differences can be divided into different factors. The deprivation model of social class and intelligence consists of three variables. These variables explain, in terms of environmental factors, development and performance which are correlated with social status.

The first of these variables consists of the combination of birth order, nutrition, and prenatal care. Children who are first born, on average score better on mental tests. There is a definite higher number of first born children among higher socioeconomic groups as opposed to lower socioeconomic groups. According to Bruce Eckland, children of higher economic class tend to be brighter, on average, than children of lower economic groups (65). Both prenatal stress and malnutrition, impair development and are found much more frequently among lower socioeconomic classes. According to Philip E. Vernon, the fetus can have lack blood supply and growth of the fetus can be disturbed if the mother takes certain drugs or suffers from certain diseases. Severe stress on the mother can also be hazardous to the fetus (84). These conditions expressed are both genetic and or resulting from environmental conditions and are known to as constitutional factors. The second variable of the deprivation model which helps exhibit differences in performance is the cultural variable. It seems that lower socioeconomic classes experience a unique pattern of behavioral and psychological traits which impair development in children raised in these conditions. The last environmental variable that accounts for differences in the cognitive development is the social cultural variable. This variable includes deprivation which involves socially structured inequalities in education and other social opportunities for improving performance. Sidney W. Bijou states that in order to help development, an ample supply of physical stimuli for cognitive development is favorable along with the people who have to manage these stimuli in contingent relationships after the birth of the child (230).

Another environmental contribution to intelligence, which Bijou points out is th...

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...ort the conclusion that both genetic and environmental components have a significant effect upon the intelligence of the child. There has also been some research done on identical twins who live in different environments.

They have been compared with siblings who are not twins but live in the same environment. The correlation results for twins who live apart is .75 and .24 for no-twin siblings who do live together. It seems that together, these two correlations almost add up to 1.00 which is the total phenotypic variance. Vernon points out that the effect of genes is much more powerful than that of the environment. Even though the precise values of the correlations are of dispute, analyses of kinship data, concludes

Vernon, provides the most convincing demonstration of genetic influence on intelligence.

Undoubtedly ,the subject of intelligence can be defined in many ways.

To better understand intelligence psychologist have rendered two main influences as cause for variable intelligence levels. These two main influences as discussed previously cannot be explained as one being the main determinant of intelligence. This two influences are environmental and hereditary influences.