light of the failures of molecular genetic research, never considering the possibility that the critics were right all along that the massive flaws and untenable theoretical assumptions of these methods explain these failures. Plomin could not name any replicated gene findings in a 2011 publication, and continued to explain these negative results on the basis of “missing heritability.”35 According to Plomin, “The big question now in molecular genetics is how to identify the ‘missing’ heritability; the big question for non-shared environment is how to identify the ‘missing’ nonshared environment.” As critics have argued, both are “missing” because behavioral geneticists have mistakenly interpreted twin studies as providing unequivocal evidence in favor of genetics. Plomin and his colleagues continue to place total faith in twin research, and continue to ignore the implications of other evidence, which includes Plomin’s own carefully performed 1998 longitudinal adoption study that found a non-significant .01 personality test score correlation between birthparents and their 245 adopted-away biological offspring. According to Plomin and his colleagues, this birthparent-biological offspring correlation is “the most powerful adoption design for estimating genetic influence,” which “directly indexes genetic influence.”36 Conclusion Science writer John Horgan published a critical appraisal of behavioral genetics in a 1993 edition of Scientific American.37 Horgan noted that although there were many gene finding claims for traits such as crime, bipolar disorder, schizophrenia, alcoholism, intelligence, and homosexuality, none of these claims had been replicated. He presented the results under the heading, “Behavioral Genetics: A Lack-of Progress Report.” We can now update Horgan’s Volume 24 Number 6
“progress report” and issue the field of behavioral genetics its apparent final report card: The evidence suggests that genes for the major psychiatric disorders, as well as for IQ and personality, do not exist. As Turkheimer concluded in 2011, in light of the failures of molecular genetic research, it is time to develop a “new paradigm.”38 Simply put, the gene finding claims and predictions by Plomin and other leading behavioral geneticists turned out to be wrong. The best explanation for why this occurred is not that “heritability is missing,” but that previous and current claims that psychiatric and psychological twin studies prove something about genetics are also wrong. We cannot expect the proponents of behavioral genetics to recognize that the historical positions of their field are mistaken, that their prized research methods and “landmark” studies are massively flawed and environmentally confounded, and that family, social, cultural, economic, and political environments—and not genetics—are the main causes of psychiatric disorders and variation in human psychological traits. Because most leaders of the field will not allow themselves to see this, it is left to others to show that the pillars of behavioral genetics are crumbling before our very eyes. We are indeed at the “dawn of a new era,” but it will be an era very different than the one that Plomin and his colleagues envisioned. nnn Jay Joseph, PsyD, is a licensed psychologist and the author of The Gene Illusion and The Missing Gene.
Race? Debunking a Scientific Myth
“New techniques and new approaches can and will tell us an enormous amount about the biological history of our species; but they also teach us that this history was a very complex one that is very inaccurately – indeed, distortingly – summed up by any attempt to classify human variety on the basis of discrete races. While we can acknowledge that our ideas of race do in some sense reflect a historical reality, and that human variety does indeed have biological underpinnings, it is important to realize that those biological foundations are both transitory and epiphenomenal. Despite cultural barriers that uniquely help slow the process down in our species, the reintegration of Homo sapiens is proceeding apace. And this places the notion of “races” as anything other than sociocultural constructs ever more at odds with reality. Increasingly, it seems, we are simply who we think we are.” - from Race? Debunking a Scientific Myth By Ian Tattersall and CRG Board member Rob DeSalle
Available from Texas A&M University Press. Order by calling 800-826-8911, or visit www.tamupress.com.
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