A recent study comparing the mental health of youth in China and the United States has shed light on the intriguing relationship between the number of siblings and psychological well-being. The findings, consistent with expectations stemming from China's One Child Policy, suggest that having more siblings is associated with poorer mental health outcomes.
Conducted among students with an average age of 14, researchers in both countries posed a series of questions related to mental health. Notably, the Chinese survey revealed that teenagers with no siblings displayed the best mental health. In contrast, the American data indicated that individuals with either no siblings or one sibling had similar mental well-being levels.
Further analysis of the US data revealed a concerning trend - both half and full siblings were linked to poorer mental health outcomes. The negative impact was particularly pronounced in cases where siblings were born within a year of each other or had a close age gap. This observation aligns with the theory of "resource dilution," which suggests that as parental resources are divided among more children, individual attention and resources diminish, potentially impacting mental health.
Dr. Downey, the lead researcher behind the study, explains, "If you think of parental resources like a pie, one child means that they get all the pie - all the attention and resources of the parents. But when you add more siblings, each child gets fewer resources and attention from the parents, and that may have an impact on their mental health."
Another theory, known as the "selectivity explanation," suggests that families with many children may differ from those with fewer children in ways that influence their children's mental health. However, the study's overall findings indicate that the selectivity explanation alone falls short in accounting for the observed effects.
While the study's results highlight the negative impact of siblings on mental health, it is important to note that the research does not delve into the quality of sibling relationships. It is likely that high-quality sibling relationships have a positive effect on children's mental well-being.
Interestingly, previous research has shown contrasting results, indicating that having more siblings is associated with improved social skills among kindergarteners and a reduced likelihood of divorce among adults. Dr. Downey emphasises that there is still much to learn about the impact of siblings on various aspects of life.