Birth Order and Intelligence
There is empirical data in research papers that suggest birth order affects intelligence in a within-family situation. There is no lack of information for your birth order and intelligence research papers and arguments regarding birth order and intelligence.
The main contentions that birth order influences intelligence come from studies on the following:
- The fact that younger siblings are influenced by older siblings and benefit from their knowledge
- The intellectual environment of the home decreases as more children are brought into it
- The number of children influences the access to tutoring
Researchers Belmont and Marolla found, in a 1973 study, that there is a negative relation of both birth order and family size with intelligence. Other birth order and intelligence research papers, such as those by Berbaum and Moreland, Galbraith, Rutherford and Sewell, and many others, reached similar conclusions, though they saw different patterns emerging when between-family data and within-family data were compared.
Rodgers suggests that virtually all studies finding differences in families regarding intelligence present significant and verifiable data only when the within-family technique is the core of the research. Between-family studies, compared against within-family data, tend to confuse the issue and do not lead to scientifically verifiable or quantifiable conclusions.
Another difficulty when trying to conclude that birth order affects intelligence is the time variation in age when the testing is performed. If a family is studied when there are, say, three children, the results will necessarily be different than if that same family is studied when there are four or more children at a later date. One researcher has stated that the intellectual environment decreases in relative quality as the number of siblings increases. He maintains that is caused by the older siblings tutoring their younger brothers or sisters, providing them with an additional intellectual benefit they themselves probably did not have.
Oldest Sibling and Intelligence
This means simply that while older siblings are learning from parents and in school, they are benefiting from several-source learning. Of course, younger siblings will ultimately have the same experiences, as well as the mentoring from older siblings. Thus, the birth-order effect regarding the intellectual level or development of children in a family tends to evaporate as each child develops his or her own learning patterns and is also coached by older siblings.