The Politics of Biology
BY WRAY HERBERT
How the nature vs. nurture debate shapes public policy--and our view of
ourselves
Read the results of an all new U.S. News Survey on
American attitudes towards human behavior
Laurie Flynn uses the technology of neuroscience to light up the brains of
Washington lawmakers. As executive director of the National Alliance for the Mentally Ill,
she marshals everything from cost analysis to moral pleading to make the case for laws
banning discrimination against people with mental illness. But her most powerful advocacy
tool by far is the PET scan. She takes a collection of these colorful brain images up to
Capitol Hill to put on a show, giving lawmakers a window on a "broken" brain in
action. "When they see that it's not some imaginary, fuzzy problem, but a real
physical condition, then they get it: `Oh, it's in the brain.'"
The view of mental illness as a brain disease has been crucial to the effort to
destigmatize illnesses such as schizophrenia and depression. But it's just one example of
a much broader biologizing of American culture that's been going on for more than a
decade. For both political and scientific reasons--and it's often impossible to
disentangle the two--everything from criminality to addictive disorders to sexual
orientation is seen today less as a matter of choice than of genetic destiny. Even basic
personality is looking more and more like a genetic legacy. Nearly every week there is a
report of a new gene for one trait or another. Novelty seeking, religiosity, shyness, the
tendency to divorce, and even happiness (or the lack of it) are among the traits that may
result in part from a gene, according to new research.
This cultural shift has political and personal implications. On the personal
level, a belief in the power of genes necessarily diminishes the potency of such personal
qualities as will, capacity to choose, and sense of responsibility for those choices--if
it's in your genes, you're not accountable. It allows the alcoholic, for example, to treat
himself as a helpless victim of his biology rather than as a willful agent with control of
his own behavior. Genetic determinism can free victims and their families of guilt--or
lock them in their suffering.
On the political level, biological determinism now colors all sorts of
public-policy debates on issues such as gay rights, health care, juvenile justice, and
welfare reform. The effort to dismantle social programs is fueled by the belief that
government interventions (the nurturing side in the nature-nurture debate) don't work very
well--and the corollary idea that society can't make up for every unfortunate citizen's
bad luck. It's probably no coincidence that the biologizing of culture has accompanied the
country's shift to the political right, since conservatives traditionally are more dubious
about human perfectibility than are liberals. As Northeastern University psychologist Leon
Kamin notes, the simplest way to discover someone's political leanings is to ask his or
her view on genetics.
Even so, genetic determinism can have paradoxical consequences at times, leading
to disdain rather than sympathy for the disadvantaged, and marginalization rather than
inclusion. Cultural critics are beginning to sort out the unpredictable politics of
biology, focusing on four traits: violence, mental illness, alcoholism, and sexual
orientation.
The nature of violence. To get a sense of just how
thorough--and how politicized--the biologizing of culture has been, just look at the issue
of urban gang violence as it is framed today. A few years ago, Frederick Goodwin, then
director of the government's top mental health agency, was orchestrating the so-called
Federal Violence Initiative to identify inner-city kids at biological risk for criminal
violence, with the goal of intervening with drug treatments for what are presumed to be
nervous-system aberrations. Goodwin got himself fired for comparing aggressive young males
with primates in the jungle, and the violence initiative died in the resulting furor. But
even to be proposing such a biomedical approach to criminal justice shows how far the
intellectual pendulum has swung toward biology.
The eugenics movement of the 1930s was fueled at least in part by a desire to
get rid of habitual criminals, and many attempts have been made over the years to identify
genetic roots for aggression, violence, and criminality. A 1965 study, for instance, found
that imprisoned criminals were more likely than other people to have an extra Y chromosome
(and therefore more male genes). The evidence linking this chromosomal aberration to crime
was skimpy and tenuous, but politics often runs ahead of the evidence: Soon after, a
Boston hospital actually started screening babies for the defect, the idea being to
intervene early with counseling should personality problems become apparent. The screening
was halted when further study showed that XYY men, while slightly less intelligent, were
not unusually aggressive.
As with many psychopathologies, criminal aggression is difficult to define
precisely for research. Indeed, crime and alcohol abuse are so entangled that it's often
difficult to know whether genetic markers are associated with drinking, criminality--or
something else entirely, like a personality trait. A 1993 National Research Council study,
for example, reported strong evidence of genetic influence on antisocial personality
disorder, but it also noted that many genes are probably involved. Getting from those
unknown genes to an actual act of vandalism or assault--or a life of barbaric
violence--requires at this point a monstrous leap of faith.
Yet it's a leap that many are willing to make. When geneticist Xandra
Breakefield reported a possible genetic link to violent crime a few years ago, she
immediately started receiving phone inquiries from attorneys representing clients in
prison; they were hoping that such genetic findings might absolve their clients of
culpability for their acts.
Mutations and emotions. Just two decades ago, the National
Institute of Mental Health was funding studies of economic recession, unemployment, and
urban ills as possible contributors to serious emotional disturbance. A whole branch of
psychiatry known as "social psychiatry" was dedicated to helping the mentally
ill by rooting out such pathogens as poverty and racism. There is no longer much evidence
of these sensibilities at work today. NIMH now focuses its studies almost exclusively on
brain research and on the genetic underpinnings of emotional illnesses.
The decision to reorder the federal research portfolio was both scientific and
political. Major advances in neuroscience methods opened up research that wasn't possible
a generation ago, and that research has paid off in drugs that very effectively treat some
disorders. But there was also a concerted political campaign to reinterpret mental
illness. A generation ago, the leading theory about schizophrenia was that this
devastating emotional and mental disorder was caused by cold and distant mothering, itself
the result of the mother's unconscious wish that her child had never been born. A
nationwide lobbying effort was launched to combat such unfounded mother blaming, and 20
years later that artifact of the Freudian era is entirely discredited. It's widely
accepted today that psychotic disorders are brain disorders, probably with genetic roots.
But this neurogenetic victory may be double edged. For example, family and
consumer groups have argued convincingly that schizophrenia is a brain disease like
epilepsy, one piece of evidence being that it is treatable with powerful antipsychotic
drugs. Managed-care companies, however, have seized upon the disease model, and now will
rarely authorize anything but drug treatment: it's efficient, and justified by the
arguments of biological psychiatry. The American Psychiatric Association just this month
issued elaborate guidelines for treating schizophrenia, including not only drugs but an
array of psychosocial services--services the insurance industry is highly unlikely to pay
for.
The search for genes for severe mental disorders has been inconclusive. Years of
studies of families, adoptees, and twins separated at birth suggest that both
schizophrenia and manic-depressive illness run in families. But if that family pattern is
the result of genes, it's clearly very complicated, because most of the siblings of
schizophrenics (including half of identical twins, who have the same genes) don't develop
the disorder. Behavioral geneticists suspect that several genes may underlie the illness,
and that some environmental stress--perhaps a virus or birth complications--also might be
required to trigger the disorder.
On several occasions in the past, researchers have reported "linkages"
between serious mental illness and a particular stretch of DNA. A well-known study of the
Amish, for example, claimed a link between manic-depression and an aberration on
chromosome 11. But none of these findings has held up when other researchers attempted to
replicate them.
Even if one accepts that there are genetic roots for serious delusional
illnesses, critics are concerned about the biologizing of the rest of psychiatric illness.
Therapists report that patients come in asking for drugs, claiming to be victims of
unfortunate biology. In one case, a patient claimed he could "feel his neurons
misfiring"; it's an impossibility, but the anecdote speaks to the thorough saturation
of the culture with biology.
Some psychiatrists are pulling back from the strict biological model of mental
illness. Psychiatrist Keith Russell Ablow has reintroduced the idea of
"character" into his practice, telling depressed patients that they have the
responsibility and capacity to pull themselves out of their illness. Weakness of
character, as Ablow sees it, allows mental illness to grow. Such sentiment is highly
controversial within psychiatry, where to suggest that patients might be responsible for
some of their own suffering is taboo.
Besotted genes. The best that can be said about research on the
genetics of alcoholism is that it's inconclusive, but that hasn't stopped people from
using genetic arguments for political purposes. The disease model for alcoholism is
practically a secular religion in this country, embraced by psychiatry, most treatment
clinics, and (perhaps most important) by Alcoholics Anonymous. What this means is that
those seeking help for excessive drinking are told they have a disease (though the exact
nature of the disease is unknown), that it's probably a genetic condition, and that the
only treatment is abstinence.
But the evidence is not strong enough to support these claims. There are several
theories of how genes might lead to excessive drinking. A genetic insensitivity to
alcohol, for example, might cause certain people to drink more; or alcoholics might
metabolize alcohol differently; or they may have inherited a certain personality type
that's prone to risk-taking or stimulus-seeking. While studies of family pedigrees and
adoptees have on occasion indicated a familial pattern for a particular form of alcoholism
(early-onset disorder in men, for example), just as often they reveal no pattern. This
shouldn't be all that surprising, given the difficulty of defining alcoholism. Some
researchers identify alcoholics by their drunk-driving record, while others focus on
withdrawal symptoms or daily consumption. This is what geneticists call a "dirty
phenotype"; people drink too much in so many different ways that the trait itself is
hard to define, so family patterns are all over the place, and often contradictory.
Given these methodological problems, researchers have been trying to locate an
actual gene (or genes) that might be involved in alcoholism. A 1990 study reported that a
severe form of the disorder (most of the subjects in the study had cirrhosis of the liver)
was linked to a gene that codes for a chemical receptor for the neurotransmitter dopamine.
The researchers even developed and patented a test for the genetic mutation, but
subsequent attempts to confirm the dopamine connection have failed.
The issues of choice and responsibility come up again and again in discussions
of alcoholism and other addictive disorders. Even if scientists were to identify a gene
(or genes) that create a susceptibility to alcoholism, it's hard to know what this genetic
"loading" would mean. It certainly wouldn't lead to alcoholism in a culture that
didn't condone drinking--among the Amish, for example--so it's not deterministic in a
strict sense. Even in a culture where drinking is common, there are clearly a lot of
complicated choices involved in living an alcoholic life; it's difficult to make the leap
from DNA to those choices. While few would want to return to the time when heavy drinking
was condemned as strictly a moral failing or character flaw, many are concerned that the
widely accepted disease model of alcoholism actually provides people with an excuse for
their destructive behavior. As psychologist Stanton Peele argues: "Indoctrinating
young people with the view that they are likely to become alcoholics may take them there
more quickly than any inherited reaction to alcohol would have."
Synapses of desire. It would be a mistake to focus only on
biological explanations of psychopathology; the cultural shift is much broader than that.
A generation ago, the gay community was at war with organized psychiatry, arguing
(successfully) that sexual orientation was a lifestyle choice and ought to be deleted from
the manual of disorders. Recently the same community was celebrating new evidence that
homosexuality is a biological (and perhaps genetic) trait, not a choice at all.
Three lines of evidence support the idea of a genetic basis for homosexuality,
none of them conclusive. A study of twins and adopted siblings found that about half of
identical twins of homosexual men were themselves gay, compared with 22 percent of
fraternal twins and 11 percent of adoptees; a similar pattern was found among women. While
such a pattern is consistent with some kind of genetic loading for sexual orientation,
critics contend it also could be explained by the very similar experiences many twins
share. And, of course, half the identical twins did not become gay--which by definition
means something other than genes must be involved.
A well-publicized 1991 study reported a distinctive anatomical feature in gay
men. Simon LeVay autopsied the brains of homosexual men and heterosexual men and women and
found that a certain nucleus in the hypothalamus was more than twice as large in
heterosexual men as in gay men or heterosexual women. Although LeVay couldn't explain how
this neurological difference might translate into homosexuality, he speculates that the
nucleus is somehow related to sexual orientation. The hypothalamus is known to be involved
in sexual response.
The only study so far to report an actual genetic connection to homosexuality is
a 1993 study by Dean Hamer, a National Institutes of Health biologist who identified a
genetic marker on the X chromosome in 75 percent of gay brothers. The functional
significance of this piece of DNA is unknown, and subsequent research has not succeeded in
duplicating Hamer's results.
Homosexuality represents a bit of a paradox when it comes to the intertwined
issues of choice and determinism. When Hamer reported his genetic findings, many in the
gay community celebrated, believing that society would be more tolerant of behavior rooted
in biology and DNA rather than choice. LeVay, himself openly gay, says he undertook his
research with the explicit agenda of furthering the gay cause. And Hamer testified as an
expert witness in an important gay-rights case in Colorado where, in a strange twist,
liberals found themselves arguing the deterministic position, while conservatives insisted
that homosexuality is a choice. The argument of gay-rights advocates was that biological
status conveyed legal status--and protection under the law.
History's warning. But history suggests otherwise, according to
biologist and historian Garland Allen. During the eugenics movement of the 1920s and
1930s, both in the United States and Europe, society became less, not more, tolerant of
human variation and misfortune. Based on racial theories that held Eastern Europeans to be
genetically inferior to Anglo-Saxon stock, Congress passed (and Calvin Coolidge signed) a
1924 law to restrict immigration, and by 1940 more than 30 states had laws permitting
forced sterilization of people suffering from such conditions as
"feeblemindedness," pauperism, and mental illness. The ultimate outcome of the
eugenics craze in Europe is well known; homosexuals were not given extra sympathy or
protection in the Third Reich's passion to purify genetic stock.
Allen is concerned about the possibility of a "new eugenics" movement,
though he notes that it wouldn't be called that or take the same form. It would more
likely take the form of rationing health care for the unfortunate. The economic and social
conditions today resemble conditions that provided fertile ground for eugenics between the
wars, he argues; moreover, in Allen's view, California's Proposition 187 recalls the keen
competition for limited resources (and the resulting animosity toward immigrants) of the
'20s. Further, Allen is quick to remind us that eugenics was not a marginal, bigoted
movement in either Europe or the United States; it was a Progressive program, designed to
harness science in the service of reducing suffering and misfortune and to help make
society more efficient.
These concerns are probably justified, but there are also some signs that we may
be on the crest of another important cultural shift. More and more experts, including
dedicated biologists, sense that the power of genetics has been oversold and that a
correction is needed. What's more, there's a glimmer of evidence that the typical American
may not be buying it entirely. According to a recent U.S. News/Bozell poll, less than 1
American in 5 believes that genes play a major role in controlling behavior; three
quarters cite environment and society as the more powerful shapers of our lives. Whether
the behavior under question is a disorder like addiction, mental illness, or violence, or
a trait like homosexuality, most believe that heredity plays some role, but not a primary
one. Indeed, 40 percent think genes play no role whatsoever in homosexuality, and a
similar percentage think heredity is irrelevant to drug addiction and criminality. Across
the board, most believe that people's lives are shaped by the choices they make.
These numbers can be interpreted in different ways. It may be that neurogenetic
determinism has become the "religion of the intellectual class," as one critic
argues, but that it never really caught the imagination of the typical American. Or we may
be witnessing a kind of cultural self-correction, in which after a period of infatuation
with neuroscience and genetics the public is becoming disenchanted, or perhaps even
anxious about the kinds of social control that critics describe.
Whatever's going on, it's clear that this new mistrust of genetic power is
consonant with what science is now beginning to show. Indeed, the very expression
"gene for" is misleading, according to philosopher Philip Kitcher, author of The
Lives to Come. Kitcher critiques what he calls "gene talk," a simplistic
shorthand for talking about genetic advances that has led to the widespread
misunderstanding of DNA's real powers. He suggests that public discourse may need to
include more scientific jargon--not a lot, but some--so as not to oversimplify the
complexity of the gene-environment interaction. For example, when geneticists say they've
found a gene for a particular trait, what they mean is that people carrying a certain
"allele"--a variation in a stretch of DNA that normally codes for a certain
protein--will develop the given trait in a standard environment. The last few
words--"in a standard environment"--are very important, because what scientists
are not saying is that a given allele will necessarily lead to that trait in every
environment. Indeed, there is mounting evidence that a particular allele will not produce
the same result if the environment changes significantly; that is to say, the environment
has a strong influence on whether and how a gene gets "expressed."
It's hard to emphasize too much what a radical rethinking of the nature-nurture
debate this represents. When most people think about heredity, they still think in terms
of classical Mendelian genetics: one gene, one trait. But for most complex human
behaviors, this is far from the reality that recent research is revealing. A more accurate
view very likely involves many different genes, some of which control other genes, and
many of which are controlled by signals from the environment. To complicate matters
further, the environment is very complicated in itself, ranging from the things we
typically lump under nurture (parenting, family dynamics, schooling, safe housing) to
biological encounters like viruses and birth complications, even biochemical events within
cells.
The relative contributions of genes and the environment are not additive, as in
such-and-such a percentage of nature, such-and-such a percentage of experience; that's the
old view, no longer credited. Nor is it true that full genetic expression happens once,
around birth, after which we take our genetic legacy into the world to see how far it gets
us. Genes produce proteins throughout the lifespan, in many different environments, or
they don't produce those proteins, depending on how rich or harsh or impoverished those
environments are. The interaction is so thoroughly dynamic and enduring that, as
psychologist William Greenough says, "To ask what's more important, nature or
nurture, is like asking what's more important to a rectangle, its length or its
width."
The emerging view of nature--nurture is that many complicated behaviors probably
have some measure of genetic loading that gives some people a susceptibility--for
schizophrenia, for instance, or for aggression. But the development of the behavior or
pathology requires more, what National Institute of Mental Health Director Stephen Hyman
calls an environmental "second hit." This second hit operates, counter-intuitively, through the genes themselves to "sculpt" the brain. So with
depression, for example, it appears as though a bad experience in the world--for example,
a devastating loss--can actually create chemical changes in the body that affect certain
genes, which in turn affect certain brain proteins that make a person more susceptible to
depression in the future. Nature or nurture? Similarly, Hyman's own work has shown that
exposure to addictive substances can lead to biochemical changes at the genetic and
molecular levels that commandeer brain circuits involving volition--and thus undermine the
very motivation needed to take charge of one's destructive behavior. So the choice to
experiment with drugs or alcohol may, in certain people, create the biological substrate
of the addictive disorder. The distinction between biology and experience begins to lose
its edge.
Nurturing potentials. Just as bad experiences can turn on
certain vulnerability genes, rich and challenging experiences have the power to enhance
life, again acting through the genes. Greenough has shown in rat studies that by providing
cages full of toys and complex structures that are continually rearranged--"the
animal equivalent of Head Start"--he can increase the number of synapses in the rats'
brains by 25 percent and blood flow by 85 percent. Talent and intelligence appear
extraordinarily malleable.
Child-development experts refer to the life circumstances that enhance (or
undermine) gene expression as "proximal processes," a term coined by
psychologist Urie Bronfenbrenner. Everything from lively conversation to games to the
reading of stories can potentially get a gene to turn on and create a protein that may
become a neuronal receptor or messenger chemical involved in thinking or mood. "No
genetic potential can become reality," says Bronfenbrenner, "unless the
relationship between the organism and its environment is such that it is permitted to be
expressed." Unfortunately, as he details in his new book, The State of Americans, the
circumstances in which many American children are living are becoming more impoverished
year by year.
If there's a refrain among geneticists working today, it's this: The harder we
work to demonstrate the power of heredity, the harder it is to escape the potency of
experience. It's a bit paradoxical, because in a sense we end up once again with the old
pre-1950s paradigm, but arrived at with infinitely more-sophisticated tools: Yes, the way
to intervene in human lives and improve them, to ameliorate mental illness, addictions,
and criminal behavior, is to enrich impoverished environments, to improve conditions in
the family and society. What's changed is that the argument is coming not from
left-leaning sociologists, but from those most intimate with the workings of the human
genome. The goal of psychosocial interventions is optimal gene expression.
So assume for a minute that there is a cluster of genes somehow associated with
youthful violence. The kid who carries those genes might inhabit a world of loving
parents, regular nutritious meals, lots of books, safe schools. Or his world might be a
world of peeling paint and gunshots around the corner. In which environment would those
genes be likely to manufacture the biochemical underpinnings of criminality? Or for that
matter, the proteins and synapses of happiness?
