Are the oldest really smarter than younger siblings? The research explains why this may be indeed true.
The Research
Petter Kristensen and Tor Bjerkendal reported their findings of a study on birth order and intelligence in the journal, Science. The oldest boy in a family seems to have a higher IQ than younger siblings in the family. Kristensen and Bjerkendal also report that if the first born dies, the next in line would become the first born and the most intelligent. Because of this, the conclusion was reached by the researchers that the social order in the family is more important than the exact birth order. [nytimes.com, June 21, 2007]
IQ Numbers
Intelligence tends to run on a bell curve. Fifty percent of the population runs between 90 and 110 on standardized intelligence tests. 25% of the population falls below 90 and 25% of the population falls above 110. Therefore, individuals with an IQ of 100 are seen as mid-range average. People with intelligence above 110 are seen as above average and those below 90 are seen as below average. A person with a 108 would be called high-average.
Study Stats
Kristensen and Bjerkendal studied the IQ results of 241,310 men drafted into the Norwegian armed forces. The men were 18 or 19 and tested between the years of 1967 and 1976. Average IQs found were:
- 1st born-103.2
- 2nd born-101.2
- 3rd born-100.0
However, if the second born had an older sibling that had died, the average IQ was 102.9.
What if a third born had two siblings die and was the oldest? IQ rose to 102.6. [nytimes.com, June 21, 2007]
Determining Factors
Researchers are now trying to determine why intelligence is linked to birth order. It is a fact that first-time mothers are probably more likely to rest during their first pregnancy because they have no other children at home to care for. The first-time mother’s body has not undergone the stress of a pregnancy. The body has not been depleted of nutrients that a baby would take during the pregnancy. Mothers-to-be with younger children at home don’t have the luxury of taking as much time to rest with a toddler demanding their time.
Physical Recovery Needed
A mother’s body needs time to recover between pregnancies. Many doctors suggest at least 2-3 years between children. If a woman becomes pregnant soon after the previous child, the body may be somewhat depleted in nutrients.
Tutoring Factor
William Glasser, MD, states that learning increases in children that tutor others. Research has shown that students that teach others increase their own knowledge by doing so. First-borns are put in positions of teaching younger siblings at home. This could be a strong component in the intelligence factor. Glasser incorporates this theory into his very successful school model, Glasser Quality Schools. The strong effect of tutoring fellow peers is explained in his recent book, Every Student Can Succeed.
Right-Brain/Left-Brain Factor
Right-brains and left-brains also vary in how they are viewed. Because right-brains are more creative and tend to not go from point A to point B, they are perceived to be less intelligent than a left-brain. Left-brains do better on standardized tests. Colleges are crying for more creative students but the very tests they use to determine admission often disqualify the students they want. FairTest: The National Center for Fair & Open Testing lists the colleges that have become ACT and SAT exempt alphabetically or by state.
Younger siblings may have no one to tutor at home and perhaps do not develop the tutoring skills of the first-born. This research has not determined the exact cause for the findings.
For more information on the study visit Science Mag.
Related articles: Famous Right Brains, Left Brains and Right Brains.
Read previous articles on Educational Issues.
Copyright article 2007 Barbara Pytel. All Rights Reserved.
