The End of Behavioral Genetics?

Abstract

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.The end of behavioral genetics? Recently the developmental psychologist, Richard Lerner, published a commentary entitled, "Another nine-inch nail for behavioral geneticists!" (Lerner, 2006). Lerner began his commentary with the lament, "Why do we have to keep reinterring behavior genetics" (p. 337), but concluded confident in the belief that a critical analysis of IQ adoption studies (Richardson & Norgate, 2006) had finally help put the field irretrievably where he felt it belonged, presumably six feet under. Singing the death knell of behavior genetics has been a popular pastime for critics of the field over the past 100 years, but critiques like that by Richardson and Norgate (2006) have done little to dampen interest in behavioral genetics. It is not that behavioral genetics is above criticism; quite the contrary there is much to criticize about the field. Rather, the reason Lerner and his fellow critics are engaged in the Sisyphean task of "reinterring" behavioral genetics is that they have failed to recognize the enormous impact the field has had on the way psychologists think about individual differences in behavior; they have failed to understand the essential nature of the behavioral genetic research paradigm.The purpose of this special issue of Acta Psychologica Sinica is, of course, to recognize the vitality of contemporary behavioral genetic research, not to mourn its demise. Nonetheless, even as we highlight research progress in the field, it can be helpful to consider how others have reacted to behavioral genetic findings, even the field's most enthusiastic critics. Behavioral genetics has often been caught up in controversy, sometimes unfairly, and an assessment of its current impact on psychology can benefit from both a discussion of the field's historical roots, with which I will begin, and speculation over its possible future, where I will end. NIH Public Access Author ManuscriptXin Li...

Early Trauma and Inflammation

“…Therefore, genetic factors are completely accounted for when comparing monozygotic twins with each other, but only partially accounted for when comparing dizygotic twins with each other. Thus, if the within-pair effect is smaller in monozygotic than in dizygotic twins, this is evidence that the association is confounded by genetic factors (29, 30). Intraclass coefficients were also calculated to determine whether genetic factors were involved in the traits under consideration.…”

The beauty, logic and limitations of twin studies

“…However, in its basic form the design focuses on discordant twin pairs only, thus disregarding concordant pairs and reducing statistical power. Newer approaches exploit all degrees of twin differences, and may examine discordance in either exposure or outcome (De Moor et al, 2008;McGue et al, 2010). Compared to the biometric model described above the cotwin control design is not a totally different approach.…”

Age, Aging, and Mental Health

“…These are favorable developments for sociology, and twin studies represent another avenue to identify how the gene-environment interplay affects the onset and course of mental disorder. A prominent hypothesis for examining how genes and environment jointly in fl uence mental disorder is known as contextual triggering (Shanahan & Hofer, 2005 ) or diathesisstress (McGue, 2010 ) . The essence of the hypothesis is that high-risk environments trigger (or exacerbate) genetic effects.…”