The scientists found that "neurotic" men—those who tend to be moody and emotional—are having fewer children, a trend that applied only to men born after 1957. In contrast, men who are open and extroverted are having more kids, and women who show up on personality tests as "conscientious" are having fewer kids, regardless of the year they were born.
Vegard Skirbekk, who led the study, theorizes that personality might play a role in Europe's declining birthrates.
The study was made possible by Norway's very detailed birth records and an integrated personality survey, which allowed the researchers to examine the connections between both female and male fertility and personality. "For men, often you don't know exactly how many children they have because information is not matched in the registries, but for Norway we have very exact information," says Skirbekk.
While the study only considers Norway, Skirbekk says that the findings likely apply more widely. "Norway is a leader country in terms of family dynamics," says Skirbekk, "Many trends that have been observed first in Norway—increasing cohabitation, divorce rates, and later marriage, for example—have then been observed later in many other parts of the world. Of course it remains to be seen if this phenomenon will also spread."
Image: Father and sons, via Shutterstock