Twins: And What They Tell Us About Who We Are (23 page)

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Authors: Lawrence Wright

Tags: #Family & Relationships, #Siblings, #Science, #Life Sciences, #Genetics & Genomics, #test

BOOK: Twins: And What They Tell Us About Who We Are
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twins, demonstrating that the chances of suffering PTSD in combat are about thirty percent heritable. The point is that even in extreme environments, individuals have different levels of genetic vulnerability.
Perhaps the reader will forgive the obvious analogy that genes and the environment are like conjoined twins, distinct but inseparable. When we look at conjoined twins, are we seeing one organism or two? They share their circulation, their digestion, their general predicament of mutual dependency. They may have separate thoughts and desires and goals, but each has to negotiate with the other to achieve what he wants. In the same way, neither genes nor the environment can be neatly teased apart from the other and treated as an individual entity. Each is a part of a complicated amalgamation.
Twins have been used to tell us so much about our development, but the most troubling question they pose concerns our existential situation: that is to say, do we have free will? Is the concept of human freedom compromised by the existence of human doppelgängersthe separated twins who discover themselves in the middle of life and find that they have lived uncanny parallel existences?
Of course, as we have seen, identical twins can be quite different from each other; just to use the example of divorce again, an identical twin is still more likely not to get divorced if his twin is divorcedit's just that his chances are greater than for a fraternal twin and much greater than for the population as a whole. Even assuming that the identical twins have similar genetic propensities for stability and companionability, those propensities are handled differently most of the time. Alcoholism appears to be partly heritable, but even so, about half of the twins who are alcoholics have a twin
 
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who is not. Genetic traits for behavior are best understood as inclinations, not as mandates. There is still a measure of choice left to us about how we behave. We can change our behavior and the course of our lives, even though it may entail a struggle against our natural tendencies to be shy, or dominating, or overweight, or to smoke or drink too much. We all know the difficulty of reforming such traits. Realizing that we are born with these inclinations might even help us tame them, since we could see them as our responsibility, rather than as some wound that has been inflicted on us by our environment.
"A philosopher who was talking about twins said that maybe it's freedom that makes identical twins different," says Lindon J. Eaves, who is a human geneticist at the Medical College of Virginia. "Frankly, I don't believe that for a minute. It could be freedom that makes them alike." Eaves runs one of the largest twin studies in the world, the Virginia 30,000, which surveys 15,000 twin pairs and their relatives. He's also an Anglican priest and has reflected on the implications of behavior genetics for the doctrine of free will. "It's a mistake to define what is human simply by what psychologists can measure. We should define what is human by what humans do, and humans behave in ways that compel us to use the word 'freedom.' You get a sense of the limitations of psychology when you look at the instances we think of as quintessentially and most beautifully human, the astounding actions that seem to take human life into a new dimensiontheir creativity, or their way of dealing with oppressionI think that's where the concept of freedom lies. That's why I believe that the way we think about free will is really naive. Quite clearly it's crass to equate genetics with determinism and environmentalism with freedom. I think human freedom
 
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means something about the capacity of the human organism not to be pushed around or dominated by external circumstances. I would argue that evolution has given us our freedom. Freedom is the ability to stand up and transcend the limitations of the environment. That capacity is something that natural selection has placed in us, because it's adaptive. So I think it's probably geneticthe quest for freedom is genetic. I can't prove it, but I think it's probably a way forward."
Certainly one can view the environment as being just as constraining of free will as the genes. In the purely environmental perspective, there is no innate genetic drive demanding to be expressed. People are blank slates who are conditioned by environment to react in expectable ways. It's almost as if there is no self except for the shadow that is cast on the environmentand if there is no self that is aware of itself outside of the environment, how can we speak of freedom? "One way of looking at it is, if you're going to be pushed around, would you rather be pushed around by your environment, which is not you, or by your genes, which in some sense is who you are," says Eaves. Put so neatly, it makes one glad to exchange one oppressor for another.
But at the same time, it raises the question of what we mean by freedom. A trait that is genetically rooted seems to be more immutable than one that is conditioned by the environmentafter all, we can change our environment, but a genetic predisposition seems to leave aside the possibility of free choice, or even consciousness of choice at all. Eaves seems to accept this idea when he speaks about subnormal personalitiespeople who are mentally retarded, for instance. "It's clear that for some people the options are fewer. The law recognizes that there are some people who for genetic or social reasons do not have what the normal human
 
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being is giventhat is, freedom. We recognize that such people should be treated differently. This is the forensic recognition of diminished responsibility, which on the whole applies to extreme cases. But in what sense does it not apply to the rest of us? If you think in genetic terms, you have to say that diminished responsibility is a mutation on the gene that causes freedom."
Free will is what we call our conscious struggle to shape our own destinies. It refers to the struggle with our selves, with the kind of people that we chose to become. Implicit in the concept of free will is the wishful notion that we can leap over the limitations of our environment and our genes, which of course we cannot do, any more than a child can jump off the bed and start to fly. Genetically, we can only make the best of what we have. People who are aware of their natures are constantly wrestling with tendencies they recognize as ingrained or inborn. That doesn't mean that they have no choice in directing those tendencies toward better or worse uses.
Finally, twins raise the question of what the self really is. Being genetically identical with another human being encroaches on our sense of being unique in the world, of having thoughts and desires and experiences that no one else knows about or can possibly share. But if tomorrow you suddenly turn a corner and find yourself looking into a human mirroryour identical separated siblingthe chances are that you will have an astonishing amount in common, despite the fact that you have lived in different homes and led entirely separate lives. It is the most narcissistic encounter imaginableto be able to stand aside and really look at your almost-self, to talk to someone else who is inside the same physical package, to experience your almost-self as others must experience you. No doubt it is exhilarating to
 
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discover another individual who is uniquely able to understand you, who seems to anticipate your thoughts before you form them. The saga of how each of you contested with life to arrive at similar places with similar points of view is an affirmation of who you were intended to be. Perhaps there is an element of the uncanny in your new relationship; you may have always thought there was something uncompleted in your life that now is resoundingly answered and fulfilled. The power of this widespread fantasy is a testament to how much we long to be understood on a deeper level than ordinary love and friendship can provide.
But at the same time, seeing yourself replicated is a shocking confrontation with the finite nature of who you really are. It is so much easier to see those limitations in others, but in your identical twin you can see the reflected limitations in yourself. You see how nature has shaped you; you grasp at once that your abilities and talents, however broad, are circumscribed. The nature of this shock is similar to those of the first time you hear yourself on a recording or see yourself on television. Of course, it's not you but a human approximation. You notice at once the differences between you, the subtle non-you things that are just a bit off, although a bystander may not be able to tell the two of you apart. After you've explored the variety of ways that you are alike, it is the differences between you that capture your attention. Perhaps that is a way of holding on to your separateness, your particular identity.
Now that you are no longer a singleton but something rare and special, an identical twin, you will be courted by researchers who want to measure every detail of your physical and psychological beings. You will discover that much of what you thought was unique to you has actually been franchised to another individual. Your bodies
 
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resemble each other and so do your minds. Let us say you are as alike as two different McDonald's restaurants in separate citiesthe same architecture, the same inner decor, the same employee uniforms, the same menu. The environment outside may be Des Moines or Dallas, but the structure of the restaurant is the same. The experience of being in either place is hauntingly unvaried.
Even if tests can't tell you apart, you know you're not the same person, despite the weird commonalities and the coincidences that make it seem as if you are inhabiting the same psychic space. But some of your selfhood has been appropriated. There is one side of you that wants your twin to be exactly like you in every detail, a perfect replica, but another side of you is struggling for air. You feel like you are being smothered by the sameness. Your specialness is being erased with every thrilling landmark of recognition.
After you finish the tests, you and your separated twin decide to indulge a fantasy that only identical twins can actually attempt: you will trade lives. You return not to your own home and job and family but to your twin's. It would be a rare set of twins who are so much alike as adults that loved ones could not tell them apart, but in your case, you and your twin are so similar that no one will guess what you're up to. When you walk into your twin's life, it seems stylistically the same. You've made similar choices in your career, and although love choices are notoriously varied even among identical twins, in this case you find your twin has made an acceptable match. You can now live out your life as someone else, while someone else occupies the place that once was yours.
Who are you now?
You are yourself. You might change everything about your identity, but you cannot change your awareness of
 
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yourself as a separate being. The fantasized twin that we carry about in our minds is not only an idealized partner in the experience of being who we are, he is also a means of escape from the life we are living. Twins have often told us that theirs is the most precious relationship imaginable, the closest experience one can have of being with another. Just by being twins, they have been able to reveal many answers to the riddles of existence. But they also show us that no matter how tantalizingly alike we may be, no one crosses the boundary between being alike and being the same. We might, as in this fantasy, be able to exchange lives, but we cannot exchange selves. There is finally no escape from being the people we were born to be.
 
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Bibliography
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The Psychoanalytic Study of the Child, 49th Edition
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Abrams, S. and Neubauer, P.B., "Hartmann's vision: identical twins and developmental organizations," in Solnit, A.J., Neubauer, P.B., Abrams, S., Dowling, S.D. (eds),
The Psychoanalytic Study of the Child, 49th Edition
, New Haven, Yale University Press, 1994
Ainslie, R.,
The Psychology of Twinship
, Northvale, Jason Aronson, 1997
Aldhous, P., "The promise and pitfalls of molecular genetics,"
Science
, 1992, 257:5067:164
, "Burt files reopened,"
Science
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Allgulander, C., Nowak, J., Rice, J.P., "Psychopathology and treatment of 30,344 twins in Sweden. II. Heritability estimates of psychiatric diagnosis and treatment in 12,884 pairs,"
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