Personality affects fertility rates, new study finds
A fascinating new study published in the European Journal of Personality examines how a person's personality type affects his probability of having children, and researchers found that the more outgoing you are, the more fertile you’re likely to be.
For the study, researchers from the International Institute for Applied Systems Analysis (IIASA) used birth registry data and personality surveys for men and women born in Norway between the years of1927 to 1968. They then combined the surveys to look for links between fertility and personality for both men and women, using questionnaire data from over 7,000 individuals.
According to the study’s lead author Vegard Skirbekk, it is usually difficult to determine precisely the number of children men have. That’s because such information is frequently not accounted for in the registries, except for Norway, which he says has “very exact information."
Results from the study revealed that personality is connected to fertility in different ways, depending on gender. For example, conscientiousness decreased female fertility, while openness decreased male fertility – and for both men and women, extraversion increased fertility.
Among neurotic or otherwise moody or emotional men, the researchers also noticed a decline in producing children, but only for men born after 1957.
For this particular group of men, the authors also note that changes in fertility could be due to how couples today increasingly postpone having children for reasons cannot be explained by the couple’s income, education or relationship status.
Population changes are also an important set of data for IIASA, which researches and projects future changes as it pertains to sustainability, climate, energy, and food security.
The proportion of men in Norway without any children by age 40 increased between 1940 and 1970, jumping from 15% to 25%. For women, that figure only marginally increased, going from 10% to 13% during that same timeframe.
Although the study focuses on Norway, Skirbekk points out that the results have wider implications.
"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," Skirbekk explained, adding that "it remains to be seen if this phenomenon will also spread."
This is the first of its kind study to examine the connection between personality and declining fertility rates in Europe. The study authors say their findings show that "childbearing in contemporary richer countries may be less likely to be influenced by economic necessities and more by individual partner characteristics, such as personality."
Source: European Journal of Personality, "Personality traits increasingly important for male fertility: evidence from Norway," published online August 5, 2013.