Doctors are looking for reasons for increased intelligence in firstborns
How does it depend on how intelligent our children are? An important point seems to be whether the child is the firstborn or whether it has older siblings. Researchers have now found that first-born children are smarter than their younger siblings.
The researchers from the Analysis Group and the University of Sydney found that firstborns had a higher IQ than their younger siblings. This effect can be measured at the age of one year. The doctors published the results of their study in the journal "Journal of Human Resources".
Do firstborn children receive more stimulation and support from their parents?
The current discovery could possibly be explained by the fact that first-born children receive more mental stimulation and support in developing thinking skills from their parents during their early years, the researchers explain.
Older siblings usually earn more money and are more educated
The result found could help explain why many firstborns have a better education later in life and usually also receive higher wages at work than their younger siblings, the doctors suspect.
Study also takes into account the family background and economic conditions
For the study, the scientists examined the data from children in the USA, which had previously been collected by the US Bureau of Labor Statistics in the so-called National Longitudinal Survey of Youth. A total of almost 5,000 children were medically monitored from birth to 14 years of age. The family background and economic conditions of the family were particularly observed, the experts explain. Then the skills (e.g. reading and vocabulary) were assessed every two years.
Doctors are studying the effects of smoking and alcohol
The researchers then used statistical methods on the data obtained to analyze how specific behavior of parents (e.g. smoking and alcohol consumption) during pregnancy was related to the child's IQ test results.
Parents provide less mental stimulation for younger siblings
The experts found that many mothers took higher risks in younger children during pregnancy. In addition, the parents provided less intellectual stimulation for younger siblings. These included activities such as reading, manual tasks and playing and learning musical instruments. Younger siblings were simply less involved in such activities, the doctors add.
A shift in parental behavior appears to be the cause of the differences
Our results suggest that a wide shift in parental behavior is a plausible explanation for the observed differences in existing education. Jobs of young people who are better paid later also seem to be related to this shift, explains author Dr. Ana Nuevo-Chiquero from the University of Edinburgh School of Economics. (as)