Tag: missing heritability

The Fourth and Fifth Laws of Behavioral Genetics

In 2000, behavioral geneticist Eric Turkheimer proposed "Three Laws of Behavior Genetics" based on what he saw as the “nearly unanimous results” of behavioral genetic studies of families, twins, and adoptees. However, critics have argued for decades that most behavioral genetic assumptions, models, concepts, “laws,” and “discoveries” do not hold up under critical examination. In 2015, a group of behavioral geneticists proposed an additional “Fourth Law of Behavior Genetics,” which states that behavioral characteristics are associated with many genes of small effect. Here I propose a “Fifth Law” of behavior genetics—actually, the only “law” one needs to know in order to properly understand this field.