"Reports of My Death Were Greatly Exaggerated": Behavior Genetics in the Postgenomic Era

Behavior genetics studies how genetic differences among people contribute to differences in their psychology and behavior. Here, I describe how the conclusions and methods of behavior genetics have evolved in the postgenomic era in which the human genome can be directly measured. First, I revisit the first law of behavioral genetics stating that everything is heritable, and I describe results from large-scale meta-analyses of twin data and new methods for estimating heritability using measured DNA. Second, I describe new methods in statistical genetics, including genome-wide association studies and polygenic score analyses. Third, I describe the next generation of work on gene × environment interaction, with a particular focus on how genetic influences vary across sociopolitical contexts and exogenous environments. Genomic technology has ushered in a golden age of new tools to address enduring questions about how genes and environments combine to create unique human lives.

Moral orientations in psychology: contrasting theoretical perspectives

BACKGROUND

The relational development systems (RDS) metamodel embodies a newly recognized scientific paradigm that stands in contrast to the nature-nurture split. It suggests that the bidirectional relationship between an organism and its environment must be the central focus of scientific inquiry.

MAIN BODY

RDS theorists suggest scientists have a moral obligation to benefit human kind. However, the potential for interventions that appear efficacious to simultaneously instigate an undesirable outcome suggests that moral clarity might not always exist in scientific practice. Contrasting RDS perspectives with life history theory highlights a pertaining disparity in approaches.

CONCLUSION

While the RDS metamodel posits many premises necessary to contemporary research, it may not yet be pragmatic to impose moral obligation on the sciences.

Interpreting estimates of heritability--a note on the twin decomposition

While most outcomes may in part be genetically mediated, quantifying genetic heritability is a different matter. To explore data on twins and decompose the variation is a classical method to determine whether variation in outcomes, e.g. IQ or schooling, originate from genetic endowments or environmental factors. Despite some criticism, the model is still widely used. The critique is generally related to how estimates of heritability may encompass environmental mediation. This aspect is sometimes left implicit by authors even though its relevance for the interpretation is potentially profound. This short note is an appeal for clarity from authors when interpreting the magnitude of heritability estimates. It is demonstrated how disregarding existing theoretical contributions can easily lead to unnecessary misinterpretations and/or controversies. The key arguments are relevant also for estimates based on data of adopted children or from modern molecular genetics research.

Agency versus structure: genetics, group membership, and a new twist on an old debate

The decoding of the human genome and advances in genetic medicine promise great advances in the prevention and treatment of disease. These powerful methodologies, though, raise serious intellectual, ethical, and practical questions when they are employed in explanations of complex higher-order behavioral and social outcomes. There can be little doubt that all human behavior reflects complex gene/environment interactions, but isolating the unique contributions of genes and environment in the explanation of overdetermined behavioral and social outcomes may not in principle be possible. When dealing with groups that differ significantly in histories of discrimination and exclusion biological explanations must be employed with caution even as they promise great strides in dealing with specific diseases.

The End of Behavioral Genetics?

Although genetic models were in the ascendance within psychology during the early 20(th) century, the association of early behavioral genetic research with the eugenics movement served to discredit the field in the eyes of many. Twin and adoption studies throughout the latter half of the 20(th) century helped to reestablish the importance of behavioral genetic models and set the stage for the current focus of the field on developing and testing models of gene-environment interplay. Research findings on developmental behavioral genetic research, gene-environment interaction, and the use of behavioral genetic models to test causal hypotheses are used to highlight the contributions of contemporary behavioral genetic research to psychological research. It is argued that future efforts to investigate models of gene-environment interplay will depend heavily of the field's ability to identify the specific genetic variants that contribute to individual differences in behavior. The anticipated yield from genome-wide association studies gives much reason to be optimistic about the future vitality of behavior genetics.