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Is one sibling too many? Based on “dilution theory,” one brother or sister could be just that.
Whether by choice or circumstance, the only child is the fastest-growing family size worldwide in developed countries even though 80 percent of us grew up with at least one sibling. That statistic is changing rapidly.
You and your sibling might get along famously or have never seen eye-to-eye on anything in childhood or now as adults. If you are starting a family or considering expanding the family you have from one child to two or more, you likely ponder the pros and cons of giving your child a sibling.
Close to 25 years ago, psychologist Douglas Downey detailed his “dilution theory.” His theory is more apt than ever in our current social and economic environment. Downey explained “dilution” this way: “Siblings are competitors for parents’ time, energy, and financial resources and so the fewer [children] the better.” He declared, “The more children in a family, the less of resources each child receives.”
Pouring all parental resources into one child helps explain why only children have an academic edge, form closer bonds with their parents, and are poised to succeed in the workplace. Downey bases his position, in part, on intellectual test results “that dilution continues to provide the most promising explanation for why children with few siblings score higher on tests of cognitive skills than children with many siblings.”
Many others have had similar and more pointed academic advantage findings throughout the last two decades.
Competition for resources also shows up among siblings in ways that ignite feelings of favoritism no matter how hard parents try to treat their children equally and fairly. Favoritism can lead to bullying and abusive behavior, which have been shown to have negative effects that can be long-lasting.
Siblings Developmentally Necessary?
You might be inclined to disagree and take the stance that children need siblings to develop good social skills. Yet, studies over the years dating back to the 1980s show only children’s social skills and personality development were quite like those of children with siblings. In one, the researchers Toni Falbo and Denise Polit looked at “the results of 141 studies and found that only children scored significantly better than other groups in achievement motivation and personal adjustment.”
Another study in Journal of Marriage and the Family reports that having a sibling or two does not make a child more social. Socially the only child’s outcome is “similar to those with siblings.” In fact, on most scores, from sociability to well-being, the evidence is positive for only children.
The science is reassuring for those who think only children need siblings to learn how to navigate the world around them, to stand up for themselves, and to be kind and caring, or that an only child might be cheated in some way.
If you are on the fence about having one child or more, the evidence is strong that you may be doing your child a favor by abandoning the idea of providing a sibling. Considering the cost of raising children, time pressures, and starting families older, it may be for you, as Downey suggests, that “Even one sibling is too many.”
Copyright @2024 by Susan Newman, Ph.D.
