The Influences of Environment and Heredity on Measured Intelligence

The Influences of Environment and Heredity on Measured Intelligence
What are the influences of environment and heredity on measured intelligence?


Psychologists are greatly divided over whether heredity or environment has a more dominant influence on individual intelligence.
Although some animal studies appear to suggest heredity have the greatest influence, a seemingly more accurate conclusion may be drawn form human studies on intelligence.
In studies on the similarities between IQ of siblings reared in the same and separate environments, the IQ of fraternal twins reared together showed greater similarity than the scores of ordinary siblings.
One may wonder why this is so! Parents tend to treat twins more alike than they do ordinary siblings. The influencing factor behind the increased resemblance in the twins IQ proves to be environmental.
Identical twins who are raised together show even greater similarities in their IQ, which is to be expected, considering their identical genes and the similar environmental influences they receive. When identical twins are raised apart the similarities in their IQ can be seen to decrease, however not by much. As the similarities are still impressive one may be lead to believe that heredity plays a major role in intelligence, but one must not overlook the fact that almost all separated twins are placed in homes socially and educationally similar to those of their biological parents. This tends to falsely increase the apparent effect of genes on intelligence, by making the separated twins IQ more alike.
Psychologists who place emphasis on environmental influence in regards to intelligence point out that in the cases where separated twins were placed in homes with significant educational and environmental differences to those of their birth parents, some twins IQ scores vary by as much as 20 points.
Other evidence, which seems to refute the influential importance of heredity on intelligence, comes from parents who raise both biological and adopted children. If genes greatly contribute to intelligence, the IQ of biological children and their parents should show greater similarities than the IQ of adopted children raised by the same parents. However, studies reveal that adopted and biological children reaised by the same mother resemble her in IQ to the same degree. The adopted children?s genetic dissimilarities seem to make no difference.

The Human brain is very much like a computer, it can be used to add numbers or fly planes it just depends on the program used.
Dr Luis Alberto Machado was elected in Venezuela (1974) as head of human intelligence. He revolutionised their learning system.
As a test he made babies, as soon as they were born, experience as many things as possible. Which included all human sensors and exercise. He decided that the mother was not only a milk source but also a mind source, so the idea that parent?s influence was important to the child?s intelligence.
Psychologists also were paid to visit the poor people to teach them better ways of thinking so that they might manage there business better, this proves that poorer people cannot not afford good education, therefore may be restricted in their environment, to stimulate their brains.
Another influence was food, as good eating habits provide the brain with energy to think and grow.
A study placed children at around the age of ten, into thinking programs. After time these children showed good problem solving skills, and were discussing issues that children five to ten years older may not even think about.
The last example of how the environment influences the IQ of children is a study that was undertaken on 25 children classed as mentally retarded, or unadoptable. These children were sent from the orphanage, into a more stimulating environment, with personal education. Later these children were all adopted. Their IQ had risen and average of 29 points, one child?s IQ rose an amazing 58 points. The children?s IQ that had been left at the orphanage dropped on average about 26 points.


Overall we found that heredity influences to a small amount into how intelligent we are. The facts on twins that were raised separately shows that genes do make up some off our intelligence. The major finding was that our environment influences greatly on our intelligence. The studies that showed that children that were placed into a different environment, that was more stimulating to the previous one they were in, tells us that the more you stimulate your mind, the greater you intelligence will be.

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