Heritability and Indirect Causation

Abstract

Genetic differences can lead to phenotypic differences either directly or indirectly (via causing differences in external environments, which then affect phenotype). This possibility of genetic effects being mediated by environmental influences is often used by scientists and philosophers to argue that heritability is not a very helpful causal or explanatory notion. In this paper it is shown that these criticisms are based on serious misconceptions about methods of behavior genetics.

Genetics of Brain Structure and Intelligence

“…One form of GE correlation can be estimated explicitly in adoption designs: the environment that parents provide their offspring (Neale 1997). Active and reactive correlations are more difficult to estimate, leading to suggestions that the notion of heritability conflicts with common sense (Sesardic 2002).…”

Sensitive and Insensitive Causation

“…Consider another example, also due originally to Jencks (in his 1980) but much discussed in the subsequent literature (for example, Block 1995, Sesardic 2003. assume that (natural) hair color is genetically caused and suppose that redheaded children are systematically beaten and mistreated because of their hair color.…”

“…Similarly, if beavers with superior dam-building abilities (that we assume have a genetic basis) are more likely as a result to live in food-rich environments and hence to be larger and more fit, their larger size is taken to be a heritable trait. The rationale for this is that when the environment is actively selected in this way, "the environmental influences can be plausibly regarded as just a way a genotype is expressed, and hence as 'a more or less inevitable result of genotype'" (Sesardic 20031005, quoting Jinks and Fulker 1970.…”

Making Sense of the Nature–Nurture Debate

“…Chapters 2, 3, and 4 are all versions of articles that Sesardic previously published (Sesardic 1993(Sesardic , 2003. In Chap.…”