Parents more important to their kid's personality than birth order
Birth order has been in the news recently on foot of a study published by Economists at the University of Edinburgh, Analysis Group and the University of Sydney. They examined data from the US Children of the National Longitudinal Survey of Youth, a dataset collected by the US Bureau of Labour Statistics. The results were published in the Journal of Human Resources.
Nearly 5,000 children were observed from pre-birth to age 14. Every child was assessed every two years. The tests included reading recognition, such as matching letters, naming names and reading single words aloud and picture vocabulary assessments.
Information was also collected on environmental factors such as family background and economic conditions. First born children had higher IQ by several points, that was detectable even at one year old.
These findings are replications of a Norwegian study in 2007 published in Science and a German study in 2015 published in the Proceedings Of The National Academy Of Sciences. One of the authors, Dr Ana Nuevo-Chiquero, suggests this is because parental behaviour changes as more children are born. They offered less mental stimulation to younger siblings and also took part in fewer activities such as reading with the child, engaging in crafts and playing musical instruments. Mothers are also less likely to breastfeed later-born children.
Does this matter? A three point spread is so small that it is unlikely to be noticed at all, but some researchers argue that such a gap at the higher end of the IQ spectrum could make the difference between getting into a top and a second grade college.
Birth order and its impact on personality has also been an area of interest to researchers for decades, stimulated by the Austrian psychiatrist Alfred Adler, a contemporary of Freud and Jung.
He proposed that birth order plays a significant role in determining personality. His theory was given further impetus by a study, published as a book in 1966. The author Frank Sulloway in his book Born To Rebel argued that the five core dimensions of personality were influenced by birth order. These dimensions, also known as the Big Five, remembered by the acronym OCEAN, were openness, conscientiousness, extraversion, agreeableness and neuroticism, and are still recognised as the central attributes of personality.
Others have challenged Sulloway's theories, pointing out that, over time, sibling relationships change and adapt. So they are not static over the life-span, but mould to the circumstances and to external factors.
Moreover, personality traits also have a genetic component as well as other environmental influences, such as relationship with parents, early adversity or trauma, family stability and social norms.
Yet, the idea that birth order can influence our children's personality has captured the public imagination, and personality profiles abound that describe each personality.
For example, first borns are said to be studious, serious and ambitious. On the negative side, they are said to have a sense of entitlement. Second borns on the other hand are said to get the worst deal, often excluded from the limelight and therefore lacking drive. They are said to be good mediators and conflict avoiders. Youngest born children are said to be spoilt and attention seeking. They are also described as rebels.
One of the problems with this type of research is that studies have difficulty controlling all the factors that influence personality and so what may seem a birth order effect may be the result of a confounder such as income, eg third born children are likely to be born into families that experience more financial difficulties than their elder siblings did.
All of this speculation may be fun and is reminiscent of reading a hororscope to predict the future, but instead of engaging in such futile predictions or reading the multiple birth order profiles that are now available online, we should accept our children unconditionally.
We parents are still the most important people in their lives and nurturing by us is more likely to shape their personality than any other element in their young lives.
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