My impression is that most people suffer from “environmental bias.” At least when they are talking about human beings, they overrate the importance of environmental factors, and underrate the importance of genetic factors. Why would they do this? Joseph Buckhalt offers an original and thought-provoking list of possible explanations:

I have tried to understand why we are so resistant to accepting the idea that intellectual ability and other human characteristics are heritable to a significant degree, and here are a few hypotheses:

a. Democratic values: Individual and group differences run counter
to our egalitarian ideals, and to reduce cognitive dissonance, we
use denial.

b. Genes are invisible: Although genes are becoming increasingly
“visible” through modern science and technology, environmental
differences are much more available to us.

c. Parent-child similarity: Most persons aren’t aware, or choose
not to remember, that their children are products of the
(invisible) genotypes of their parents, rather than their

d. Extended families: Extended families in America tend less and
less to grow up and live near enough one another for family
resemblance to be noticed in extended kin.

e. Rapid cultural change and slow genetic change: Our environments
have changed so fast during the last century due to rapid
technological advances, that we over-attribute the influence of
environment and under-attribute to genetic change, which is
exceedingly slow relative to a human lifespan.

f. Non-agrarian society: Unlike the majority of the last 10,000
years when humans were involved in growing plants and raising
animals, and the even longer span of millions of years when we
coexisted in habitats with plants and animals, agriscience and
technology have enabled us to escape our direct connection to
nature. Americans of just a few generations ago might have
understood implicitly that many traits are the joint product of
breeding and husbandry.

g. Religious myths: The myth that humans are somehow separate and
above other species on earth continues to persist and thrive. Even
if we all understood Mendelian genetics and Darwinian evolution,
many would resist the idea that human traits are subject to these
natural laws due to their special status as creations in God’s

I don’t know if it’s true, but I find (f) to be the most intriguing. Are farmers more hereditarian than urbanites? Are more agricultural countries more hereditarian than industrial countries? Anyone?