Traditional, quantitative behavioral geneticists and developmental psychobiologists such as Gilbert Gottlieb have long debated what it would take to create a truly developmental behavioral genetics. These disputes have proven so intractable that disputants have repeatedly suggested that the problem rests on their opponents' conceptual confusion; whilst others have argued that the intractability results from the non-scientific, political motivations of their opponents. The authors provide a different explanation of the intractability of these debates. They show that the (...) disputants have competing interpretations of the concepts of reaction norm, genotype-environment interaction, and gene. The common thread that underlies each of these disagreements, the authors argue, is the relevance of potential variation that is not manifest in any actual population to the understanding of development. (shrink)

FOREWORD. Gilbert Gottlieb and the Developmental Point of View. I. INTRODUCTION. 1. Developmental Systems, Nature-Nurture, and the Role of Genes in Behavior and Development: On the Legacy of Gilbert Gottlieb. 2. Normally Occurring Environmental and Behavioral Influences on Gene Activity: From Central Dogma to Probabilistic Epigenesis. II. THEORETICAL FOUNDATIONS FOR THE DEVELOPMENTAL STUDY OF BEHAVIOR AND GENETICS. 3. Historical and Philosophical Perspectives on Behavioral Genetics and Developmental Science. 4. Development and Evolution Revisited. 5. Probabilistic (...) Epigenesis and Modern Behavioral and Neural Genetics. 6. The Roles of Environment, Experience, and Learning in Behavioral Development. 7. Contemporary Ideas in Physics and Biology in Gottlieb’s Psychology. III. EMPIRICAL STUDIES OF BEHAVIORAL DEVELOPMENT AND GENETICS. 8. Behavioral Development during the Mother-Young Interaction in Placental Mammals: The Development of Behavior in the Relationship with the Mother. 9. Amniotic Fluid as an Extended Milieu Interieur. 10. Developmental Effects of Selective Breeding for an Infant Trait. 11. Emergence and Constraint in Novel Behavioral Adaptations. 12. Nonhuman Primate Research Contributions to Understanding Genetic and Environmental Influences on Phenotypic Outcomes across Development. 13. Interactive Contributions of Genes and Early Experience to Behavioural Development: Sensitive Periods and Lateralized Brain and Behaviour. 14. Trans-Generational Epigenetic Inheritance. 15. The Significance of Non-Replication of Gene-Phenotype Associations. 16. Canalization and Malleability Reconsidered: The Developmental Basis of Phenotypic Stability and Variability. IV. APPLICATIONS TO DEVELOPMENT. 17. Gene-Parenting Interplay in the Development of Infant Emotionality. 18. Genetic Research in Psychiatry and Psychology: A Critical Overview. 19. On the Limits of Standard Quantitative Genetic Modeling of Inter-Individual Variation: Extensions, Ergodic Conditions and a New Genetic Factor Model of Intra-Individual Variation. 20. Songs My Mother Taught Me: Gene-Environment Interactions, Brain Development and the Auditory System: Thoughts on Non-Kin Rejection, Part II. 21. Applications of Developmental Systems Theory to Benefit Human Development: On the Contributions of Gilbert Gottlieb to Individuals, Families, and Communities. (shrink)

More than 40 years ago, Gilbert Gottlieb and like-minded scholars argued for the philosophical necessity of approaching genetic contributions to development through a multilevel, bidirectional systems perspective. Charney's target article builds on this heritage in significant ways, offering more recent examples of the interactions of biology and context, as well as the diversity of developmental mechanisms, and reaffirming a way forward for genetic research.

A theory is presented to explain how accurate, single-joint movements are controlled. The theory applies to movements across different distances, with different inertial loads, toward targets of different widths over a wide range of experimentally manipulated velocities. The theory is based on three propositions. (1) Movements are planned according to “strategies” of which there are at least two: a speed-insensitive (SI) and a speed-sensitive (SS) one. (2) These strategies can be equated with sets of rules for performing diverse movement tasks. (...) The choice between SI and SS depends on whether movement speed and/or movement time (and hence appropriate muscle forces) must be constrained to meet task requirements. (3) The electromyogram can be interpreted as a low-pass filtered version of the controlling signal to the motoneuron pools. This controlling signal can be modelled as a rectangular excitation pulse in which modulation occurs in either pulse amplitude or pulse width. Movements to different distances and with loads are controlled by the SI strategy, which modulates pulse width. Movements in which speed must be explicitly regulated are controlled by the SS strategy, which modulates pulse amplitude. The distinction between the two movement strategies reconciles many apparent conflicts in the motor control literature. (shrink)

Behavioral geneticists sometimes use metaphorsto describe the role of genes in humanbehavior. In this paper, five sample texts areanalyzed: a popular book, a textbook, ascientific review article, and two originalscientific articles representing differentapproaches in behavioral genetics. Metaphorsare found in all the different kinds of sampletexts, not only in the popular book and thetextbook. This suggests that metaphors are usednot only for rhetorical or pedagogical purposesbut play a more fundamental role in scientificunderstanding. In the sample texts, themetaphors tend (...) to be antideterministic, i.e.,they do not imply genetic determinism butstress the interaction of multiple genes andmultiple environmental factors. No conclusioncan be drawn, however, as to whetherantideterminism is representative ofpresent-day behavioral geneticists in general.Certain historically important metaphors thatmay imply genetic determinism are qualified,avoided, or explicitly rejected. There aretensions between some of the metaphors, makingthem difficult to combine. All the metaphorsthat are used appear empirically apt, howeversometimes only with certain qualifications. (shrink)

Several new molecular findings and concepts furnish evidence in support of geneneogenomicsclassical” behavioral genetics modeling.

Since Darwin, there has been a long and arduous struggle to understand the source and maintenance of natural genetic variation and its relationship to phenotype. The reason that this task is so difficult is that it requires integration of detailed, and as yet incomplete, knowledge from several biological disciplines, including evolutionary, population, and developmental genetics. In this ‘post‐genomic’ era, it is relatively easy to identify differences in the DNA sequence between individuals. However, the task remains to delineate how this (...) abundant genetic diversity actually contributes to phenotypic diversity. This necessitates tackling the problem of hidden genetic variation. Genetic polymorphisms can be conditionally cryptic, but have the potential to contribute to phenotypic variation in particular genetic backgrounds or under specific environmental conditions. A recent paper by Lauter and Doebley highlights the contribution of hidden genetic variation to traits characterizing the morphological evolution of modern maize from its wild grass‐like progenitor teosinte.1 This work is the first to demonstrate hidden variance for selected (agronomically ‘adaptive’) traits in a well‐characterized model for morphological evolution. BioEssays 24:685–689, 2002. © 2002 Wiley Periodicals, Inc. (shrink)

Discussions of information produced by genetics research are often guided by two mistaken theoretical moves. Enthusiasts tell us not to worry because genetic tinkering can alter only our body, never our soul; worriers suggest that discovering links between our behavior and our different bodies threatens important democratic ideas like moral equality. If we understand the body and soul to be inseparable and equality to be undiminished by difference, we can begin to take seriously the information produced by genetics (...) research. (shrink)

Our incomplete understanding of carcinogenesis may be a significant reason why some cancer mortality rates are still increasing. This lack of understanding is likely due to a research approach that relies heavily on genetic comparison between cancerous and non‐cancerous tissues and cells, which has led to the identification of genes of cancer proliferation rather than differentiation. Recent observations showing that a tremendous degree of natural human genetic variation occurs are likely to lead to a shift in the basic paradigms of (...) cancer genetics, in that there is a need to consider both the nature of the genes involved, and the idea that not every genetic variation identified in these genes may be associated with carcinogenesis. Based on studies using LCM and micro‐genetic analyses, we propose that significant cancer initiating events may take place during the very early stages of development of cancer‐susceptible tissues and that using such techniques might greatly help us in our understanding of carcinogenesis. BioEssays 29:678–685, 2007. © 2007 Wiley Periodicals, Inc. (shrink)

I am in the process of trying to organize an ethics committee at a large community mental health center in Central Massachusetts and am seeking advice from anyone with experience in this or a similar milieu. The agency is a large (almost 700 employees), nonprofit, community-based program that operates under the auspices of a broad, academically affiliated, behavioral health system. An independent board of trustees, responsible to the parent organization governs the agency. The agency primarily provides outpatient care and (...) treatment to adults and children with mental health, substance abuse, developmental disabilities, and homelessness issues. It does not provide any psychiatric emergency or acute in-patient mental health services but does operate an inpatient detoxification unit for substance abuse treatment and DUI program. Additionally, the agency has a vast network of residential programs and transitional facilities for individuals with a history of chronic mental illness and substance abuse problems. Outpatient medical care is also provided to homeless clients who reside in area shelters (including a shelter for men and women) and a large number of clients who have HIV/AIDS and/or who have been dually diagnosed (substance abuse and mental illness), and are part of a scattered-site supportive housing program. (shrink)

Models of central control variables (CVs) that are expressed in positional reference frames and rely on proprioception as the dominant specifier of muscle activation patterns have not yet been shown to be adequate for the description of fast, voluntary movement, even of single joints. An alternative model with illustrative data is proposed.

This book is a collection of essays on recent findings in behavioural genetics and on the appropriate ethical, social and legal reactions to these findings. The authors come from various fields. The collection does not attempt to answer systematically all the questions it raises, but I believe that the book might be of some use in attempting to systematise and analyse the ethical problems in this area.Journal of Medical Ethics 2001;27:68–71 Behavioural genetics is not in itself a new (...) field of research. We are painfully aware of the claims made for the existence of genetic factors in behaviour throughout the twentieth century. “Eugenics” is today charged with very negative feelings, and there is a risk that any claim by modern scientists about a genetic basis for behaviour, such as intelligence, will arouse these feelings. …. (shrink)

The 29 commentaries amplified our key arguments; offered extensions, implications, and applications of the framework; and pushed back and clarified. To help forge the path forward for cultural evolutionary behavioral genetics, we (1) focus on conceptual disagreements and misconceptions about the concepts of heritability and culture; (2) further discuss points raised about the intertwined relationship between culture and genes; and (3) address extensions to the proposed framework, particularly as it relates to cultural clusters, development, and power. These commentaries, (...) and the deep engagement they represent, reinforce the importance of integrating cultural evolution and behavioral genetics. (shrink)

For much of its history, behavioral genetics, or research into the influence genetics has on human behavior, has been associated with a pessimistic view of educational reforms’ potential to make much difference in improving educational outcomes or reducing inequality. Recently, however, some behavioral geneticists have begun to speak in more optimistic terms about the promise of genetically informed education to improve learning for all children, especially those who are socially or economically disadvantaged. This shift in emphasis (...) should be welcome news for everyone interested in promoting educational improvement who worried that behavioral genetics offered support for the status quo. However, I think it amounts to little more than a shift in tone. Behavioral genetics, I will argue, does not advance educational reform: its proposed solutions are rooted in the limits, not the strength, of behavioral genetics knowledge; repeat the ideas of earlier U.S. educational reform efforts; and rely on a naive optimism about the power of choice and personalization. (shrink)

To understand public discourse in the United States on genetic causation of behavioral disorders, we analyzed media representations of genetic research on addiction published between 1990 and 2010. We conclude first that the media simplistically represent biological bases of addiction and willpower as being mutually exclusive: behaviors are either genetically determined, or they are a choice. Second, most articles provide only cursory or no treatment of the environmental contribution. A media focus on genetics directs attention away from environmental (...) factors. Rhetorically, media neglect the complexity underlying the etiology the addiction and direct focus back toward individual causation and responsibility. (shrink)

In this rejoinder to the three preceding comments, I provide some additional philosophical warrant for the biomedical sciences' focus on model organisms. I then relate the inquiries on model systems to the concept of 'deep homology', and indicate that the issues that appear to divide my commentators and myself are in part empirical ones. I cite recent work on model organisms, and especially C. elegans that supports my views. Finally, I briefly readdress some of the issues raised by Developmental Systems (...) Theory. (shrink)

Behavioral genetic (BG) research has yielded many important discoveries about the origins of human behavior, but offers little insight into how we might improve outcomes. We posit that this gap in our knowledge base stems in part from the epidemiologic nature of BG research questions. Namely, BG studies focus on understanding etiology as it currently exists, rather than etiology in environments that could exist but do not as of yet (e.g., etiology following an intervention). Put another way, they focus (...) exclusively on the etiology of “what is” rather than “what could be”. The current paper discusses various aspects of this field-wide methodological reality, and offers a way to overcome it by demonstrating how behavioral geneticists can incorporate an experimental approach into their work. We outline an ongoing study that embeds a randomized intervention within a twin design, connecting “what is” and “what could be” for the first time. We then lay out a more general framework for a new field—experimental BGs—which has the potential to advance both scientific inquiry and related philosophical discussions. (shrink)

Behavioral genetics typically finds that the so-called shared environment contributes little or nothing to explaining within-population variation on most traits. If true, this has important implications for where not to look for good targets of interventions: Namely all things that are within the normal range of variation from one rearing environment to the next in that population.

Behavioral genetics has as its goal the discovery of genes that play a significant causal role in complex phenotypes that are socially relevant such a parenting, aggression, psychiatric disorders, intelligence, and even race. In this article, I present the stories of the discoveries of three such important phenotypes: maternal nurturing behavior and the c-fosB gene; intelligence and phenylketonuria ; and pair-bonding and monogamy and show that the reality is considerably more complex than often portrayed. These accounts also lay (...) bare some fundamental misconceptions of this field in which genes hold a privileged place and inherently subjective phenomena are mistakenly objectified. (shrink)

The posterior parietal cortex and frontal eye field contain maps of visual salience on which the decision to choose a saccade may be based. However, an averaging express saccade is not represented by a victorious unimodal representation in the superior colliculus. Normalization as described by Findlay & Walker is not necessary for the generation of saccades.

The exponential growth of genetic knowledge and precision medicine research raises hopes for improved prevention, diagnosis, and treatment options for children with behavioral and psychiatric conditions. Although well-intended, this prospect also raise the possibility — and concern — that behavioral, including psychiatric genetic data would be increasingly used — or misused — outside the clinical context, such as educational settings. Indeed, there are ongoing calls to endorse a “personalized education” model that would tailor educational interventions to children's (...) class='Hi'>behavioral and psychiatric genetic makeup. This article explores the justifications for, and prospects and pitfalls of such endeavors. It considers the scientific challenges and highlights the ethical, legal, and social issues that will likely arise should behavioral genetic data become available and are routinely incorporated in student education records. These include: when to disclose students' behavioral and psychiatric genetic profile; whose genomic privacy is protected and by whom; and how students' genetic data may affect education-related decisions. I argue that the introduction of behavioral genetics in schools may overshadow the need to address underlying structural and environmental factors that increase the risk for psychiatric conditions of all students, and that the unregulated use of student behavioral genetic profiles may lead to unintended consequences that are detrimental for individuals, families and communities. Relevant stakeholders — from parents and students to health professionals, educators, and policy-makers — ought to consider these issues before we forge ahead with a genomically informed education system. (shrink)

Executive functions (EFs) and impulsivity are dimensions of self-regulation that are both related to psychopathology. However, self-report measures of impulsivity and laboratory EF tasks typically display small correlations, and existing research indicates that impulsivity and EFs may tap separate aspects of self-regulation that independently statistically predict psychopathology in adulthood. However, relationships between EFs, impulsivity, and psychopathology may be different in childhood compared to adulthood. Here, we examine whether these patterns hold in the baseline assessment of the Adolescent Brain and Cognitive (...) Development (ABCD) sample, a national sample of over 11,000 children (including 749 twin pairs) ages 9–10 years. We examine the phenotypic and genetic relationships among latent variables for different components of EFs and multiple facets of impulsivity. Additionally, we assess how EFs and impulsivity relate to composite measures and latent variables of psychopathology derived from parent report. EFs were weakly correlated with impulsivity, and the strength varied by impulsivity facet, emphasizing their separability. We did not identify significant genetic and environmental correlations between EFs and impulsivity. Moreover, controlling for their small relationships with each other, both EFs and some facets of impulsivity statistically predicted an Externalizing factor, attention problems, and social problems, and twin analyses suggested these relationships were genetic in origin. These findings indicate that EFs and impulsivity represent phenotypically and genetically separable aspects of self-regulation that are both transdiagnostic correlates of psychopathology in childhood. (shrink)

The differentiation of mammalian neurons during development is a highly complex process involving regulation and coordination of gene expression at multiple steps. The P19 mouse embryonal carcinoma cell line is a suitable model system with which to analyze regulation of neuronal differentiation. These multipotential cells can be maintained and propagated in tissue culture in an undifferentiated state. Exposure of aggregated P19 cells to retinoic acid results in the differentiation of cells with many fundamental phenotypes of mammalian neurons. Undifferentiated P19 cells (...) are amenable to genetic manipulations such as transfection and establishment of stable clonal cell lines expressing introduced genes. Proteins that play a key role in the neuronal differentiation of P19 cells are beginning to be identified. These include retinoic acid receptors, the epidermal growth factor receptor and the transcription factors Oct‐3 and Brn‐2. The biological and technical advantages of this system should facilitate deeper analysis of the activities of proteins that play a role in neuronal differentiation. (shrink)