As a mother, pediatrician, and sister, I recognize all too well how different siblings can be. One brother might be a bookworm, the other a jock. One sister an optimist, the other a cynic.
Like me, you probably wonder how people from the same genes and the same environment can end up being so different.
In the 1980s, Robert Plomin, a psychologist specializing in twin studies and behavior genetics, discovered something interesting (as summarized by Alix Spiegel in the article Siblings Share Genes, But Rarely Personalities). In regards to physical characteristics and intelligence, siblings were fairly similar. But when it came to personality, they were more like strangers. In fact, their personalities were similar “only about twenty percent of the time.”
That finding prompted the scientific community to ask:
How can children raised in the same family have such different personalities?
According to Spiegel’s article, three theories surfaced:
Given human nature, children compete with each other for their parents’ attention. As a result, if one child excels in academics, another might choose sports, hoping to stand out to his or her parents.
Though on the outside it appears children in the same family share the same environment, they really don’t. Because kids differ in age, they’ll experience family events differently, particularly difficult events like divorce or death. For example, a mother’s cancer diagnosis will have different effects on a five-year-old than a twelve-year-old, and as such, each child will have different needs. The parents will then treat each child differently based on these needs. This in turn molds different personalities.
Children in the same family are often compared to each other, and their differences, even if minor, might be exaggerated. For example, “Oh, she’s the talkative one.” Or, “he’s the trickster.” Before long a label is born, reinforcing the trait and perhaps even escalating it over time.
Surely other variables mold our personalities, including neurochemical factors, but I suspect these theories hold some truth.
So what got me started down this road of contemplation? My sister, a talented singer and songwriter, has recently branched out with her new band, ADHD. As I looked through the group’s page on Reverbnation and watched and listened to my extroverted sister sing and dance with a beer bottle in her hand, I thought, “Holy cow, how can we be so different?”
And then I thought, “Holy cow, my sister is really talented!”
My favorite song she wrote is “Suffocate” (the first one listed under songs). When I heard it, I couldn’t stop singing it.
But of course, as an introvert, only in the privacy of my own home…
Are you and your siblings different?
* * *