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Birth Weight Affects Social Trust in Adulthood

Birth Weight Affects Social Trust in Adulthood

A new study has found that our birth weight tends to correlate with our trust levels as adults. Specifically, low birth weight is tied to low levels of social trust in adulthood, while high birth weight is associated with high levels of trust, according to researchers from Aarhus School of Business and Social Sciences (Aarhus BSS) at Aarhus University, Denmark.

“Social trust is extremely important for society. In many ways, it is what keeps society together. When we sort our waste, when we vote, when we pay our taxes, it’s all a function of how much trust we have in one another,” says lead researcher Michael Bang Petersen from the Department of Political Science at Aarhus BSS.

“Therefore, it’s fascinating that we can trace trust all the way back to the embryonic stage. It helps us understand why some people involve themselves more than others in society, and why some are less involved.”

In one survey, a large number of participants were asked if they believed that “a person cannot be too careful when dealing with other individuals” or if “most people can be trusted.” Responses that reflected a low level of trust tended to correlate with low birth weight.

The link remained even after researchers controlled for genetic and environmental factors as measured by the birth weight of siblings. Siblings share family environment and, on average, 50 percent of the genes. If the correlation between low birth weight and low trust remains even after taking genetics and family environment into account, it supports the idea that factors linked to the embryonic stage have an impact on adult life.

The researchers were inspired by the fact that studies often look back at childhood for explanations of adult behavior. They decided to go one step further in showing that even the time before birth can affect the development of the individual.

“A lot of earlier research suggests that experiences in early childhood affect how you react psychologically as an adult. We wanted to investigate if experiences in the embryonic stage also have an impact on psychological patterns in adulthood,” said Petersen.

The findings could serve as an argument for ensuring safe and ample material conditions for women during pregnancy. More importantly, they represent an instance of basic research which adds to our understanding of man and his role in modern society, and helps us appreciate the factors that decide how we interact with each other.

Who feels a sense of belonging, and who feels detached? Who wants to contribute to the community, and who sees less of a reason to do his share? These are quite fundamental questions.

“Our findings match findings in disciplines such a biology and psychology which have shown, on the one hand, that women’s ability to care for their children is highly dependent on the amount of social support they receive from their surroundings, and, on the other hand, have demonstrated that children are very much influenced by signals from the environment about the kind of world we’re living in, and whether it’s a cold and uncaring place, or a safe one,” said researcher Lene Aarøe, also from the Department of Political Science at Aarhus BSS.

“Social trust is at the very core of modern society and shapes how citizens interact. By achieving a better understanding of the factors that lead to social trust we also get closer to understanding the basic elements that ensure social coherence,” said Aarøe.

The article is published in the journal Psychological Science.

Source: Aarhus University


Birth Weight Affects Social Trust in Adulthood

Traci Pedersen

Traci Pedersen is a professional writer with over a decade of experience. Her work consists of writing for both print and online publishers in a variety of genres including science chapter books, college and career articles, and elementary school curriculum.

APA Reference
Pedersen, T. (2018). Birth Weight Affects Social Trust in Adulthood. Psych Central. Retrieved on November 24, 2020, from
Scientifically Reviewed
Last updated: 8 Aug 2018 (Originally: 30 Sep 2015)
Last reviewed: By a member of our scientific advisory board on 8 Aug 2018
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