The age-old dynamics of sibling relationships, often portrayed in literary works like Cain and Abel or Cinderella, have come under scrutiny in a recent study. Researchers now posit that adolescents complaining about their siblings might have legitimate concerns, as a study conducted in the United States and China reveals a correlation between the number of siblings and teenagers’ mental well-being.
The research, involving secondary school students, found that adolescents from larger families exhibited slightly lower levels of mental health than their counterparts from smaller families. Notably, families with multiple children born within a year of each other experienced the greatest impact. Doug Downey, a sociology professor at Ohio State University, emphasized that while previous studies presented a mixed picture regarding the effects of having more siblings, the latest findings were not predetermined.
The study, encompassing 9,100 eighth graders in the United States and 9,400 in China, with an average age of 14, involved inquiries into various aspects of mental health. In China, teenagers without siblings demonstrated the best mental health outcomes, while in the United States, those with no siblings or only one showed similar mental health levels.
The overarching trend revealed that mental health tended to decline as the number of siblings increased, particularly for teenagers with older siblings and those born in close succession. Downey and his colleagues, in their publication in the Journal of Family Issues, argue that these findings align with the “resource dilution” theory. This theory posits that parental attention and resources are akin to a finite pie, with each additional child receiving a smaller share, potentially impacting their mental well-being.
Notably, teenagers with the most favorable mental health outcomes tended to come from families with higher socioeconomic advantages, often characterized by having only one or two children. China’s one-child policy played a role in a significant proportion of Chinese children being only children, contrasting with 12.6% of American children falling into this category.
As societal trends shift towards smaller families, researchers are increasingly interested in unraveling the nuanced impact of sibling relationships on mental health and other factors. Previous studies have suggested both positive and negative impacts associated with having siblings, presenting a complex landscape of advantages and disadvantages. Earlier research by Downey indicated that children with more siblings exhibited better social skills in nursery settings and were less likely to divorce later in life, potentially due to their early experience navigating close relationships. Additionally, a 2016 study of over 100,000 Norwegian children found better mental health outcomes across various age groups in larger families.
