Researchers have dismissed the idea of ‘middle child syndrome’, saying the order in which your child is born has no impact on their personality.
German researchers analysed data from 20,000 people from three nations – in the most comprehensive and largest study on birth order – and found that birth order had no effect on extroversion, emotional stability, agreeableness, conscientiousness and imagination.
It debunks previous theories from other experts that first-borns, middle children and the baby of the family have distinct personality traits, but it it also supported earlier findings that the first child in a family is likely to be more intelligent.
The study, published in Proceedings of the National Academy of Sciences, was co-authored by Julia Rohrer, from the University of Leipzig. She says the link between birth order and personality was first initiated in the early 1900s by psychiatrist and philosopher Alfred Adler, the second of six children.
He claimed firstborns were privileged, but also burdened by feelings of excessive responsibility and a fear of dethronement.
“Whether you have younger or older siblings appears to be of such great importance as a child, that the assumption that this has a lasting impact on personality just seems natural,” Ms Rohrer tells the ABC. “I think there are some biases at work that help firm those beliefs. For example, parents might infer their firstborn is emotionally unstable and very anxious because their infant cries a lot and is easily scared.”
“The second-born child might actually cry just as much, but now the parents already know that this is just the way that children are, and stop attributing this behaviour to the child’s character,” Ms Rohrer says.
Ms Rohrer’s team used data from three large national studies in Great Britain, the US and Germany and undertook a range of analyses and looked for effects that were evident within families. The finding that birth order had no lasting impact on later personality traits was consistent across all three national studies, across the different measures of personality and across the participants’ whole life span, she says.
Ms Rohrer says the study did confirm IQ is impacted by birth order and said it is likely due to social effects rather than biological.
“One theory is that later children ‘dilute’ the resources of the parents, including attention,” she says. “While the firstborn gets full parental attention for at least some time, laterborns would have to share from the beginning.”