Every year, thousands of twins (and other multiples) flock to Twinsburg, Ohio for the Twins Days Festival, a long weekend of wild, rollicking twin-related festivities (a Double-Take Parade, talent shows, a wiener roast, and something called, rather unsettlingly, the ‘Corn Hole Tournament’). An almost equal horde of researchers across a wide range of disciplines – behavioral scientists, geneticists, neurobiologists, even dentists and corporate marketing gurus – descend on the festival-goers, eager for the unique opportunity to study genetic doppelgangers.
Identical twins separated at birth really get the researchers salivating, and competition for their time and cooperation is fierce. Part of the tremendous interest in these cases, of course, is the hope of gaining insight into the age-old debate of Nature v. Nurture, which in recent years has begun to tip dramatically toward the ‘nature’ side of the argument, largely due to advances in our understanding of genetics.
Before we had kids, my wife and I sat fairly firmly in the ‘nurture’ camp, our feelings nicely summed up in George Howe Colt’s amazing Life magazine article “Were You Born That Way?”
IN THE DEBATE OVER THE RELATIVE POWER OF nature and nurture, there may be no more devout believers in nurture than new parents. As my wife and I, suffused with a potent mix of awe, exhaustion and ego, gazed down at our newborn daughter in the hospital, it was hard not to feel like miniature gods with a squirming lump of figurative putty in our hands. We had long believed that people could make the world a better place, and now we firmly believed that we could make this a better baby. At home our bedside tables were swaybacked by towers of well-thumbed parenting manuals. A black-and-white Stim-Mobile, designed to sharpen visual acuity, hung over the crib. The shelves were lined with books, educational puzzles and IQ-boosting rattles. Down the line we envisioned museum visits, art lessons, ballet. And if someone had tapped us on the shoulder and told us that none of this would matter, that in fact we could switch babies in the nursery and send our precious darling home with any other new parents in the hospital, and as long as those parents weren’t penniless, violent or drug addicted, our daughter would turn out pretty much the same.., well, we would have thwacked that someone with a Stim-Mobile.
Now that we have kids, we’ve more or less switched camps – or, more accurately, have a foot in each camp. In addition to the rapidly-growing body of scientific – particularly genetic – research that demonstrates a hereditary aspect to everything from obesity to optimism, from religious conviction to coffee consumption, we have the evidence right there in front of us. Our boys are, and have been right from the beginning, very, very, different.
Our oldest has always been somewhat shy, introverted, some might say ‘dark’ in a Romantic-with-a-capital-r sense. In a Caspar David Friedrich, “The Sorrows of Young Werther” kind of way. When he was still a young toddler, he spurned the happy, upbeat songs we would try to play for him, claiming that they weren’t “angry enough”. Angry enough. From a two year-old. One Christmas, he astounded his cousins, aunts, uncles, and grandparents by launching unbidden into a chorus from Linkin Park. “I’ve become so numb….,” he growled with a toddler’s imperfect pronunciation, “…all I want to do, is be more like me and be less like you.” My mother gave me a look at once commiserating and triumphant, and pronounced, “You’re going to have a lot of trouble with this one.” (‘Triumphant’ because she had had so much trouble with me.)
If our eldest is something of a storm cloud, an incorrigible pessimist, our youngest is an unswervingly optimistic ray of sunshine. If we’ve announced that we’re going on a hike, the 6 year-old will say, to no one in particular, that it will probably rain. Our 2 year-old says “That’ll be great!” The contrasts are stark, and go on and on.
Never a thumb sucker
Great night sleeper, terrible napper
Would rather be indoors
Won’t touch most fruit
Frequently car sick
Never says ‘I love you’
Inveterate thumb sucker
Terrible night sleeper, great napper
Hates to be inside
Can’t get enough fruit
Not fond of meat
Never car sick
Says ‘I love you’ 1,000,000 times a day
This last one is something of a stinger for me. While our oldest would tell his mom that he loved her when he was little, round about the age of four he stopped. It seems to embarrass him. On my part, I could count on one hand the number of times he’s told me he loves me. That, I must confess, is fairly high on my list of ‘things in the world which I think kind of suck’, right behind the wholesale destruction of the Earth’s environment and the kind of toy packaging that requires a box cutter, a razor blade, and a blow torch but still takes 10 minutes to open.
Now, how is it that these two kids are so different in so many ways? Sure, there have been small variables in where we’ve lived, the stages of our careers, their time spent with a nanny, the inevitable differences in the way you raise a second child as opposed to your first. But these can’t begin to account for the tremendous divergence in their personalities, the antithetical nature of their outlooks on life.
Reenter the twins. A famous case is outlined by Colt: In 1979 two men, steelworker Jim Lewis and a clerical worker named Jim Springer, met for the first time. “Identical twins separated five weeks after birth, they were raised by families 80 miles apart in Ohio. Reunited 39 years later, they would have strained the credulity of the editors of Ripley’s Believe It or Not. Not only did both have dark hair, stand six feet tall and weigh 180 pounds, [well, but they are identical twins, after all] but they spoke with the same inflections, moved with the same gait and made the same gestures. Both loved stock car racing and hated baseball. Both married women named Linda, divorced them and married women named Betty. Both drove Chevrolets, drank Miller Lite, chain-smoked Salems and vacationed on the same half mile stretch of Florida beach. Both had elevated blood pressure, severe migraines and had undergone vasectomies. Both bit their nails. Their heart rates, brain waves and IQs were nearly identical. Their scores on personality tests were as dose as if one person had taken the same test twice.”
Some of these similarities may be attributed to analogous upbringings (how many working-class males in Ohio in the late ‘70s drank Miller Lite and smoked Salems?), some to chance, but those explanations only go so far, and even critics had to admit that there seemed to be an incredibly strong genetic influence on behavior.
Now, some findings seem to me to require a healthy dose of skepticism. There is, according to scientists at the Minnesota Center for Twin and Adoption Research, a genetic predisposition to drink coffee, but none for tea. “Assertiveness” is 60 percent heritable, while “the ability to be enthralled by an aesthetic experience” is 55 percent heritable. ‘Happiness’ is “80 percent heritable – it depends little on wealth, achievement or marital status.” Not only do such terms seem inherently subjective, but the precise percentages suggest scientific overstatement.
But wait, these examples show similarities, not differences. Indeed they do. But what twins neatly demonstrate in their very sameness is how much of what we perceive as received personality and preferences are in fact genetically programmed. So unlike the metaphor of a piece of putty, a child’s brain is, in Colt’s words, “more like a computer’s motherboard, her basic personality hardwired into infinitesimal squiggles of DNA.”
Our experience with our boys would seem to bear that out. They are hugely dissimilar in almost every way, despite being raised in nearly identical circumstances. It appears that your best efforts, your Baby Einstein and your Goodnight Moon, your sunshine-yellow nursery with the Winnie-the-Pooh mural on the wall, your pre-natal classical music and your agonies over choosing just the right name may be less important than the genetic information you pass on the instant that tenacious little spermatozoon penetrates the ovum to form Billy and the Zygotes.
Now no one would say that the way in which you raise your children has little to do with how they turn out, it’s just that many of the aspects of their personality may be pre-determined. And of course the nature v. nurture debate isn’t exclusively one-or-the-other – it’s just a question of the percentages of the mix, of the proportions of ingredients that go into making the finished dish.
So if our two boys are so vastly different in terms of their personalities, one might inevitably be led to ask: Which do you prefer? Ah, dear reader, that’s a perilously loaded question, and one that I will not answer for a variety of reasons, but the most important being that it is unanswerable. I prefer whichever one is being more pleasant at that particular moment and that, like nature v. nurture, is a question of degrees.