Sibling gender doesn’t shape personality traits

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The gender of our siblings doesn’t affect our personalities, research finds.

Siblings play a central role in childhood, and so it seems reasonable to assume that they influence each other’s personalities in the long term. In fact, psychological research has been dealing with the question of what difference it makes whether people grow up with sisters or brothers for more than half a century.

Scientists have repeatedly investigated whether brothers and sisters influence the extent to which their siblings adopt gender-conforming characteristics, i.e. characteristics that are considered typically male or typically female in society. There are many assumptions and also contradictory findings on this, which may reflect that earlier studies were often based on limited and not very robust data.

In order to shed light on the previously inconsistent data situation, collaborators on the new study analyzed data from more than 80,000 adults from nine countries, including China, Germany, Mexico, and the United States.

They used various national longitudinal studies that systematically collect information about people over decades, including their living conditions and personality traits. Statistical analysis of this data show that—across national borders—personality traits such as risk-taking, emotional stability, conscientiousness, and patience are not systematically related to sibling gender.

“Our findings refute the idea that growing up with brothers or sisters causes us to develop certain personality traits in the long term that are considered ‘typically female’ or ‘typically male’ in a society,” explains study coauthor Julia Rohrer of the Leipzig University, who worked with collaborators at the University of Zurich and Victoria University in Wellington, New Zealand. Their findings appear in the journal Psychological Science.

“Overall, current research suggests that siblings have a surprisingly small impact on personality in adulthood. For example, previous studies by our research group here in Leipzig show that sibling position—that is, whether a person is a firstborn or a [middle] child, for example—also does not play a major role in personality.”

However, the results of the new study do not mean that sibling gender does not play a role at all in long-term life paths. Economic studies have shown that in the US and Denmark, women with brothers earn less when employed. “So there do seem to be some interesting dynamics here that are related to gender,” says Rohrer. “But personality is probably not part of the explanation for such effects.”

Source: University of Zurich