Wrestling with Behavioral Genetics
Full Title: Wrestling with Behavioral Genetics: Science, Ethics, and Public Conversation
Author / Editor: Erik Parens, Audrey R. Chapman and Nancy Press (Editors)
Publisher: Johns Hopkins University Press, 2006
Review © Metapsychology Vol. 10, No. 36
Reviewer: James Sage, Ph.D.
This volume of edited essays aims
to provide tools, information, and resources to help guide a public dialogue
concerning behavioral genetics. Supported by several grants and working in
close partnership with The Hastings Center, the American Association for the
Advancement of Science (AAAS), and funded largely by the Ethical, Legal, and
Social Implications (ELSI) division of the National Human Genome Research
Institute, the editors and contributing authors were united by the idea that
behavioral genetics, while largely misunderstood by the general public,
nevertheless occupies a central role in a number of socio-political issues.
The editors and collection of
interdisciplinary contributors (all of whom are outstanding in their
specialties) were commonly motivated by the worry that much of the general
public lacked an accurate understanding of the issues raised by behavioral
genetics (this misinformation is especially true regarding the abbreviated
journalistic treatment of genetics offered in modern mass media). Instead of
waiting and hoping that some serious, in-depth, careful journalism takes place,
this thoughtful group of researchers, scholars, philosophers, and historians
took it upon themselves to translate the complex (and interesting!) field of
human behavioral genetics to the general public directly.
The volume, then, speaks to this
missing piece of public discourse regarding the field of behavioral genetics by
providing a basic introduction to the history of the field, the current factual
understanding within the field, as well as an open and candid discussion of the
controversies and difficulties facing the field. As a philosopher of science, I
found this volume to be an excellent introduction to the field; it was also
quite valuable in its ability to pull together both science and public policy
issues.
All in all, this volume of essays
covers topics including: basic science and history of science (biology,
genetics, mental health, etc.); social ethics, public policy and criminal
justice; as well as social/political aspects of public discourse in an open and
democratic society. While several chapters are challenging to non-specialists,
they are well worth reading for a broad range of interested people (from
scientist to philosopher, from public health administrators to elected
officials).
In what follows, I will provide
some brief details about significant parts of each of the three Parts. Given
the immense amount of information contained in this volume, however, my
discussion will be quite abbreviated. Overall, the volume is highly recommended.
Part I: Basic Scientific Concepts and Debates
In this first Part, five chapters
are devoted to tracing both the historical and contemporary developments within
the field of behavioral genetics. Part I is designed to get the reader up to
speed on the basics of terminology, concepts, and methods.
In the first two chapters,
historian and philosopher of science Kenneth Schaffner provides an invaluable
introduction to the field of behavioral genetics. Rather than providing a long
list of terms and concepts, Schaffner presents his overview as a series of
three dialogues between a fictional State Supreme Court Judge ("Judge Jean")
and a Behavioral Geneticist (with no other nickname except "BG").
In any event, such a format lends
itself to an approachable, conversational-style that allows for both basic and
complex issues to be raised and understood. Throughout the course of these
dialogues, Schaffner introduces such terms as: DNA, chromosomes, alleles,
genotype, phenotype, locus/loci, environment, norms of reaction, traits, and
behavior. He also introduces a number of related concepts such as: heritability
(both broad and narrow), variation, the equal environments assumption (EEA),
etc.
Also within these dialogues,
Schaffner is careful to discuss "big picture" ideas, such as the
basic split within behavioral genetics between quantitative approaches and
molecular approaches, and the types of studies within each general approach
(e.g., family studies, twin studies, adoption studies; linkage analysis and
allelic association).
Finally, Schaffner weaves into his
dialogues a number of specific topics to help Judge Jean (and the reader)
follow along. These examples include: the genetic basis of IQ, novelty seeking
and risk taking (and criminality), ADHD, and schizophrenia.
Readers should not be worried,
however, by this conversational style. Schaffner is able to skillfully convey
an amazing amount of information about behavioral genetics while also keeping
the reader’s attention. Schaffner also introduces a number of criticisms and
difficulties associated with the field of behavioral genetics and explains, in
the context of the above cases, how researchers are actively adjusting their
methods and assumptions to improve the reliability of their findings.
On the topic of criticisms and
difficulties, Jonathan Beckwith (professor in the Department of Microbiology
and Molecular Genetics, Harvard Medical School) provides a sober account of the
current state of the field of behavioral genetics. Not pulling any punches, Beckwith
provides a series of pointed criticisms, including challenges regarding the "equal
environments assumption" (introduced by Schaffner), problems associated
with twin studies and family studies, difficulties regarding the molecular
approach (especially difficulty of linking multiple genetic influences for a
single complex behavioral pattern, such as schizophrenia), and a number of
problems posed by the various techniques associated with statistical analysis.
Throughout this discussion,
however, the reader is not discouraged as to the potential growth and improved
understanding associated with such a field. Despite the considerable challenges
faced by researchers, Beckwith’s discussion does not leave the reader with a
sense of despair. His message, in a nutshell: Yes, the field of behavioral
genetics faces challenges, but the researchers in the field are hard at work to
make sense of them.
In a somber and reserved chapter,
Eric Turkheimer (Professor of Psychology, University of Virginia) discusses a
number of worries associated with the use of twin studies. Specifically,
Turkheimer introduces three different models of explanation within behavioral
genetics: "one-environment-one-effect" (OEOE) model is the simplest;
the "quantitative environmental effect" (QEE) model is more complex
(relying on multiple regression and other statistical techniques); and finally
they "gloomy" model is the most complex (a model that identifies far
more numerous variables than can be teased out).
The introduction of these three
models allows Turkheimer to discussion two other important issues. First, it
allows him to discuss the difference between statistical models (whether overly
simple or prohibitively complex) and causal models: even if statistical models
could prove to be accurate and reliable, it’s still not clear that such models
help us to understand the causal links between genes, environment, and
behavior. Moreover, statistical models lend little help to the area of
intervention and therapies.
Second, the discussion of these
models allows Turkheimer to trace three parallel genetic models (again, from
simple to hopelessly complex). And this means that the hopes of ever
discovering the "genes for" schizophrenia or intelligence or juvenile
delinquency are "pathetically futile". Regarding these models,
Turkheimer states, "Which of these causal models you choose to believe in
depends on the particular balance of scientific optimism versus realism you
prefer" (p. 107).
More significantly, however, his
discussion of these different models helps to illustrate a fundamental
challenge faced by the entire field of behavioral genetics. In a nutshell, here
is the challenge: when conducting careful studies (sorting out the relative
influence of shared/nonshared environment and genetics), researchers commonly
uncover significant environmental influence as well as significant genetic
influence (depending on the behavioral trait under investigation). So,
researchers know that genes and/or the environment contributes significantly to
such complex traits as intelligence or criminality. But when researchers
attempt to identify precisely what in the genome or the environment contributes
to the trait in question, the apparent effect of the condition disappears.
Broadly speaking, then, we know
that "our genes" or "the environment" is significantly
responsible for phenotypic effects in different cases; but when scrutinized
more carefully, no single (identifiable) element of "our genes" or "the
environment" seems to significantly contribute to the expression of the
phenotype in question. While statistically relevant, upon further examination,
the causal influence of such conditions seems to evaporate.
Needless to say, this is a
fascinating riddle, and contributes to Turkheimer’s "gloomy" (yet
humble and patient) perspective.
Finally, rounding out Part I is a
chapter by Steven Hyman (Professor of Neurobiology, Harvard University) on the
broad topic of the "promises and risks" of behavioral genetics. While
Turkheimer (in the previous chapter) expresses some gloomy sentiments, Hyman
expresses what he takes to be more of a nightmare. As the former Director of
the National Institute of Mental Health, Hyman provides the background leading
to his nightmarish outlook on human behavioral genetics.
With a mixture of history and
personal narrative, Hyman conveys a number of key points, including a general
skeptical take on the human genome project with regard to its prospects for
contributing meaningful causal explanations for mental illnesses. In this
chapter, Hyman lays out a number of background factors leading up to the idea
that identifying relevant characteristics of the human genome would help to
contribute to both the diagnosis and treatment of mental illness. This discussion
focuses on the notions of genetic complexity and the difficulties associated
with identifying clearly defined phenotypes of mental illness and behavior.
While cautious and hopeful during
his tenure as Direct of the NIMH, in this chapter Wyman expresses deep
reservation as to the future of molecular explanations of mental illness and
the overall contribution of molecular genetics to public health policies.
Part II: Basic Ethical and Social Concepts and Problems
In the group of essays comprising
Part II, we find a number of fascinating "case studies" illustrating
the close connection between behavioral genetics and social issues. The first
essay (summarized below) introduces the reader to various important concepts,
such as the social construction of phenotypes and the notion of medicalization
(especially interesting in the area of mental illness). The other essays each
carve out a specialized niche of their own, including: the legal dimensions of
genetics; societal notions of fairness, equality, and justice; the use of those
who are arrested and/or incarcerated populations in genetics research; the
notions of race and economic class; the relationship between impulsivity and
criminality; the freewill/determinism debate (both philosophical and legal); and
the notion of "normality".
In the essay "Social
Construction and Medicalization" Nursing Professor Nancy Press introduces
the notions of "social construction" and "medicalization".
This essay is a very balanced and reasonable discussion (unlike some discussions
of social constructivism that are out there). Instead of inflammatory remarks
and quasi-philosophical assertions, Press’s presentation is thoughtful and on
the mark.
Essentially, Press claims that one
of the fundamental challenges faced by behavioral genetics is what’s called "the
phenotype problem" or "the problem of phenotype definition".
(Within philosophy of biology, this is a problem with biological trait
individuation.) Press makes the case that the phenotypes that get our attention
(and become the focus of behavioral genetics research) are social
constructions: phenotypes are clusters of features or traits that are thought
to be real, grouped together by our tendencies to conceptualize the world in a
specific way. But this is especially tricky for behavioral phenotypes (i.e., "the
type A personality") or categories of mental illness (i.e., "the
manic-depressive"). Since the categories picking out mental illness are
socially-constructed clusters of behavioral and dispositional traits, it makes
the phenotype incredibly difficult to pin down (and especially difficult to
find repeatable and/or cross-cultural empirical support). These problems are
generally known as problems of construct validity.
But the problem of the social
construction of phenotypes doesn’t end with mental illnesses; the problem
applies to every other major psychological/behavioral phenotype that gets our
attention: intelligence, memory, learning, leadership, and "personality"
in general.
And the real problem for the field
of behavioral genetics is that these socially-constructed categories of
behavior, psychology, and psychopathology are forming the bedrock of behavioral
genetics, which renders the entire field vulnerable to errors regarding
construct validity.
Press goes on to discuss two
additional topics worthy of brief mention: the first is the (problematic)
distinction between disease and illness. Some insist that the distinction
allows us to say that illness is socially constructed, according to which
illness is understood as the lived experiences of those who live with various
symptoms and/or disabilities (including those family members of those with such
symptoms and/or disabilities).
Clearly, this seems agreeable:
people from different societies and cultures will have different "experiences"
disease (whether it is mental illness, diabetes, or what have you). But what
the distinction between illness and disease also enables the idea that
underlying illness is a very real notion called "disease" that
apparently escapes the grip of social construction. It is this maneuver (which
amounts to reifying disease) that Press find problematic: invoking the
illness/disease distinction allows people to acknowledge some social
construction (in the domain of illness), but then it allows them to maintain
the reality of disease independent of our conceptualizations. Press explains
her position carefully, and she is quite convincing.
The second topic addressed in Press’s
essay is the idea of "medicalization" (including the "geneticization"
of various pathologies). Most directly, to be "medicalized" is to be
brought under the purview of medicine. When various (clusters of) behaviors are
recognized by our socially constructed conceptual schemes and labels them as
pathologies (such as ADHD or aggressiveness), what soon follows is the
temptation to "pathologize" such conditions. Once pathologized, such
conditions can then be treated under the rubric of medicine. What Press
suggests is that in addition to medicalizing behavior, we are embarked on yet
another stage of development: to "geneticize" various behaviors by
finding their genetic underpinnings
And, presumably, this tendency to
medicalize / geneticize is accompanied by the inclination to find "treatments"
or "therapies" or "remedies" for such genetic "maladies"
ranging from ADHD, shyness, homosexuality, novelty-seeking, alcoholism, etc.
And this, of course, raises all sorts of ethical questions. Each of the essays
in Part II takes up a handful of such issues and provides careful normative
analysis (including legal, ethical, and social aspects of such questions).
The other essay from Part II I
would like to discuss at length is the essay by philosopher Dan Brock ("Behavioral
Genetics and Equality"). This outstanding essay weaves together a number
of key arguments regarding the influence of behavioral genetics with issues of
equality. Brock is able to navigate this territory with amazing clarity and
illustrative examples (or thought experiments from the philosopher’s "idea
lab"). Brock identifies two broad "consequences" of genetic
advances that may impact issues of equality.
The first consequence of genetics
research has to do with the idea that natural differences between people
(thanks to the "genetic lottery" of chance) will (to some degree)
come under our control, including such broad traits as intelligence, physical
skill, behavioral aptitudes, etc. This means that we might (someday) be in the
position to manipulate our children’s biological inheritance to a significant
extent.
The second consequence of genetics
research has the potential to influence our beliefs regarding people’s equal
moral worth (which itself depends on our belief about their natural equality as
persons, sharing a common human nature). Genetics research has the potential to
undermine the belief in equality between all humans by the application of
direct manipulation ("enhancement") of an individual’s genetic
endowment.
Brock provides a detailed treatment
of both potential consequences and traces the philosophical worries associated
with each. In the first case, among the worries is that the ability to "overcome"
the "genetic lottery" will be largely unavailable to many people
because of the costly nature of such therapies. This introduces the notion of inequality
based on socio-economic class. The other worrisome (potential) outcome is that
such genetic manipulations will further exacerbate social inequalities by
producing biological inequalities. So, rather than using genetic therapy for "leveling
the playing field" (i.e., to compensate for difference in natural genetic
endowments or to remove socially-based disadvantages), Brock is worried that
such therapies will serve the interests of only the wealthy minority, giving
them access to genetic "enhancements" for their offspring that will
continue to increase the inequalities among individuals in society.
On the other hand, the potential to
genetically manipulate new generations of humans has the worrisome consequence
of undermining our belief in equal moral worth of all persons. With real
genetic differences emerging as a result of genetic therapies, human beings
will be challenged to continue to maintain a kind of egalitarian assumption.
Inequalities that arise will not be merely the result of the "genetic
lottery" but a form of socially-caused inequality.
Side note: while reading Brock’s
essay, I was continually reminded of the ideas presented in the film "Gattaca"
which portrays a future human society in which the economically privileged are
able to genetically screen and select their offspring. This film illustrates
many such issues of equality raised by Brock’s essay. Together, the film and
this essay could provide a valuable pedagogical tool, bringing a bit more rigor
and a rich philosophical discussion to a popular film. Of course, the film also
exaggerates a number of things, so the incorporation of popular media into an
otherwise serious debate requires some careful guidance.
Part III: Promoting Public Conversation about Behavioral
Genetics
Part III contains three chapters
which provide an excellent set of ideas, tools, and strategies for engaging in
public discourse on issues related to behavioral genetics. For example, in the
chapter "Creating Public Conversation about Behavioral Genetics," philosopher
Leonard Fleck presents 15 "norms" or recommendations for facilitating
"rational democratic deliberations" about behavioral genetics.
These norms include such things as:
identifying and discussing various internal conflicts participants may have;
the value of including factual information from scientific studies; the process
of giving reasons for one’s views; the goal of identifying public interests (as
opposed to private interests); the importance of respecting value pluralism
within a liberal political state; the tendency to engage in the deliberative
process in a fair and impartial manner; treating each other respectfully as
equals; fostering tolerance and mutual understanding; as well as the ability to
identify assumptions (both within oneself and others) and to identify
consequences of various policy recommendations.
In all, this chapter presents an
enormously rich resource for anyone interested in creating a public
conversation about behavioral genetics; I believe that it can also serve as a
workable model for how to generate meaningful public discourse on a variety of
issues (say, the relationship between creationism and evolution, public policy
issues regarding social assistance programs, and socio-political worries
regarding the role of corporations in government, etc.). Many of Fleck’s "norms"
also form the bedrock of sound pedagogical advice for discussing emotionally
charged ethical issues in courses such as bioethics and environmental ethics.
In their essay, "Laypeople and
Behavioral Genetics" authors Celeste Condit, Roxanne Parrott, and Tina
Harris report their findings of focus group research (utilizing transcripts
from 17 different focus groups). The authors, all of whom are either
researchers and/or professors in Communication and/or Speech Communication,
report a number of crucial factors that suggest that laypeople have largely
complex (but also fairly accurate) views regarding the influence of genes on
behavior.
The authors clustered and
summarized the focus group responses around four main models of genetic
influence: (i) the "equal genetic capacities" model, (ii) the "environment
catalyzes different predispositions" model, (iii) the "malleable
genetic predisposition" model, and (iv) the "you’ve gotta play the
hand you’re dealt" model.
Analyzing their findings in terms
of these four general models helped to identify they aspects according to which
laypeople had similar/different views than professional genetics researchers.
Their findings, roughly, were this:
- that laypeople have already generally incorporated the
idea that genes play a role in human behavior (in some cases attribute far
more role to genes than do researchers, while in other cases attributing
far less role to genes); - that laypeople have a nuanced view of both genetic and
environmental influences on human behavior (subscribing neither to genetic
determinism nor environmental determinism); - that laypeople are interested in a much larger array of
human behaviors than researchers have dared to explore (probably a
consequence of both experimental constraints, funding restrictions, and
the imposition of ethical standards on human subjects); - that laypeople’s ascription of the role of genetics in
human behaviors varies depending on the behavior; - that laypeople tended to include only immediate family and
childhood experiences in the realm of "the environment" rather
than larger, social institutions that shape our cultural environment; and
finally… - that many laypeople express the same critical worries
about behavioral genetics research as to the "disciplined"
critics.
In the final essay, "Behavioral
Genetics and the Media," Rick Weiss (Staff Writer for the Washington Post)
discusses a number of issues related to the role of the media in conveying the
various scientific findings of behavioral genetics.
Throughout the volume, authors had
hinted at the role of the media in shaping public understanding. Many of those
previous authors were quite critical of the abbreviated and distorted picture
of genetics research provided by popular media.
In the essay by Weiss, we find a
careful treatment of much of the science reporting on behavioral genetics,
tracing the history of the reporting on such topics as manic-depression,
homosexuality, alcoholism, and schizophrenia. Weiss presents an analysis of
several key news reports on scientific findings, noting both the positive and
negative aspects of the stories. Importantly, Weiss notes that it is
irresponsible for science journalists to oversimplify the science, admonishing
journalists with the following advice:Â refrain from writing that there is a "gene
for" any trait or that genes "cause" behaviors; include
sufficient details (and qualifications) of the research being reported; avoid "glamorizing"
lead-ins; include sophisticated details about genetics (don’t dumb-down the
reporting!); try to balance the dual desires of (i) absolving people of blame
for their genuine illnesses, and (ii) giving people a sense of control over
their lives.
Given that many of the demands of
commercial newspaper business are at odds with the state of modern genetics
research, Weiss urges science writers to keep the above tenets in mind when
reporting the latest findings in science. With wisdom and wit, Weiss is able to
portray some of these "business demands" of modern news reporting,
including the problem of "The Shrinking New Hole" (the diminishing
space in print news for actual news as opposed to photos and advertising) and
the problem of the "Shameless Marketing of Science" (how scientists
and science organizations are engaged in promotion of their work to a wider
audience via news reports).
Weiss concludes his essay with five
"basic rules" of science journalism that he presents as a personal
mission statement for himself, and useful as a model for others. He also
recommends that science reporters remember two key questions that need to be
asked with more frequency when conducting interviews or researching the latest
findings in science: "What do you mean?" and "How do you know
that?"
I believe that this is also good
advice for those of us who read science journalism (or anything for that
matter).
As a whole, this volume of essays
includes a broad array of topics and case studies. It also provides the reader
with important background information about the science of behavioral genetics,
the types of studies and approaches found within the discipline, as well as an
inventory of careful critiques. Instead of a universal promotion of behavioral
genetics, this volume presents a fair and honest treatment of the field that is
both cautious at times and also optimistic and hopeful.
© 2006 James Sage
James
Sage is Assistant Professor of Philosophy at the University of
Wisconsin-Stevens Point. Â In addition to teaching courses in epistemology,
philosophy of science, and philosophy of technology, he also has interests in
philosophical psychology and the history of science.