Wednesday, February 1, 2023

Tag: equal environment assumption

Schizophrenia Twin Research as Reported in The Gene: An Intimate History...

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In his 2016 book The Gene: An Intimate History, cancer physician and researcher Siddhartha Mukherjee chronicled the initial idea of the gene, taking readers through the history of genetics up to the current “post-genome” period by interweaving science, social history, and his own personal narrative. In the process he documented some of the crimes of the eugenics movement and the monstrous atrocities committed by German National Socialism in the name of eugenics and biology, while noting the Nazi’s promotion of twin research. He also criticized aspects of intelligence testing and genetic theories of racial inferiority based on IQ tests. At the same time, Mukherjee supported and promoted many contemporary behavioral genetics positions.

Twin Method Assumptions are Indefensible, but are Useful to the Rich...

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The wealthy, and the institutions they finance and promote, look favorably upon research whose authors claim that economic disparities are rooted in biology, and are not harmful to humanity as a whole. But there are countless obvious real-world examples showing that political policies, social struggles, and public health programs, including those involving the adjustment of income differences, lead to improved health and well-being.

Schizophrenia and Genetics: A Closer Look at the Evidence

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“The substantial hereditary component in schizophrenia,” a pair of researchers wrote in 1993, “is surely one of the two or three best-established facts in psychiatry.” But is it really? For mainstream psychiatry and psychiatric genetics, schizophrenia is “a severe mental disorder with a lifetime risk of about 1%, characterized by hallucinations, delusions and cognitive deficits, with heritability estimated at up to 80%,” or a “highly heritable neuropsychiatric disorder of complex genetic etiology.” Many commentators have challenged these claims, and some have challenged the concept of schizophrenia itself.

A Debate on Twin Research Has Broken Out in American Criminology

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The long-running debate on the validity of twin research recently resurfaced in American criminology, and has major implications for behavioral and medical twin research. Most twin researchers and their critics agree that reared-together monozygotic (MZ) twin pairs experience more similar environments than experienced by same-sex dizygotic (DZ) pairs, and we argue that the twin method is therefore unable to disentangle the potential influences of genes and environment on human behavioral differences, a conclusion supported by the failures of molecular genetic research.