The Fourth Law of Behavior Genetics?

Written by: Stephen Hsu

Primary Source: Information Processing

I believe the law stated below almost follows from the observation that humans brains are complex machines: hence the DNA blueprint has many components, and variance is spread over these components  :^)

However, note the evidence for discrete genetic modules of large effect in other species: Discrete genetic modules can control complex behavior (burrowing behavior in cute mouse in picture at bottom), As flies to wanton boys are we to the gods (discrete genetic controls on drosophila behavior).


Christopher F. Chabris, Union College
James J. Lee, University of Minnesota Twin Cities
David Cesarini, New York University
Daniel J. Benjamin, Cornell University and University of Southern California
David I. Laibson, Harvard University

Behavior genetics is the study of the relationship between genetic variation and psychological traits. Turkheimer (2000) proposed “Three Laws of Behavior Genetics” based on empirical regularities observed in studies of twins and other kinships. On the basis of molecular studies that have measured DNA variation directly, we propose a Fourth Law of Behavior Genetics: “A typical human behavioral trait is associated with very many genetic variants, each of which accounts for a very small percentage of the behavioral variability.” This law explains several consistent patterns in the results of gene discovery studies, including the failure of candidate gene studies to robustly replicate, the need for genome-wide association studies (and why such studies have a much stronger replication record), and the crucial importance of extremely large samples in these endeavors. We review the evidence in favor of the Fourth Law and discuss its implications for the design and interpretation of gene-behavior research.

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Stephen Hsu
Stephen Hsu is vice president for Research and Graduate Studies at Michigan State University. He also serves as scientific adviser to BGI (formerly Beijing Genomics Institute) and as a member of its Cognitive Genomics Lab. Hsu’s primary work has been in applications of quantum field theory, particularly to problems in quantum chromodynamics, dark energy, black holes, entropy bounds, and particle physics beyond the standard model. He has also made contributions to genomics and bioinformatics, the theory of modern finance, and in encryption and information security. Founder of two Silicon Valley companies—SafeWeb, a pioneer in SSL VPN (Secure Sockets Layer Virtual Private Networks) appliances, which was acquired by Symantec in 2003, and Robot Genius Inc., which developed anti-malware technologies—Hsu has given invited research seminars and colloquia at leading research universities and laboratories around the world.
Stephen Hsu

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