Invitation to Psychology

ChapteR 10 Behavior in Social and Cultural Context 353

point out that both sets of attitudes would

have had adaptive benefits over the centuries:

Conservatism would have promoted stability, tra-

dition, and order, whereas liberalism would have

promoted flexibility and change (Graham, Haidt,

& Nosek, 2009; Haidt, 2012).

These findings are provocative, but be careful

not to oversimplify—say, by incorrectly assuming

that everyone’s political opinions are hardwired

and unaffected by events. One factor that accounts

for even more of the variation in political attitudes

than heritability is individual life experiences,

or what behavioral geneticists call the nonshared

environment (Alford,

Funk, & Hibbing,

2005 ; see Chapter 2).

Another is genera-

tional, reflecting the

shared experiences

of your age group:

Attitudes toward gay

marriage, for example, have changed dramatically

in a relatively short time; among most people

younger than age 30, it’s practically a non-issue.

a person advocates social change or supports the
system as it is, and (2) whether a person thinks
inequality is a result of human policies and can be
overcome, or is inevitable and should be accepted
as part of the natural order (Graham, Haidt, &
Nosek, 2009). Liberals tend to prefer the values
of progress, rebelliousness, chaos, flexibility, femi-
nism, and equality, whereas conservatives tend
to prefer tradition, conformity, order, stability,
traditional values, and hierarchy. In a study of
undergraduates, liberal students were more likely
than conservative students to have favorable atti-
tudes toward atheists, poetry, Asian food, jazz,
street people, tattoos, foreign films, erotica, big
cities, recreational drugs, and foreign travel—
all examples of “openness to experience” rather
than preference for the familiar (Jost, Nosek, &
Gosling, 2008).
You can see why liberals and conservatives
argue so emotionally over issues such as gun con-
trol and gay marriage. They are not only arguing
about the specific issue, but also about underly-
ing assumptions and values that emerge from
their personality traits. Evolutionary psychologists

0 0.10 0.20 0.30

Proportion of variance accounted for

0.40 0.50 0.60 0.70

= Nonshared

environment

= Heritability

School prayer

Property tax

The draft

Unions

X-rated movies

Immigration

Death penalty

Censorship

Living together

Gay rights

Segregation

Nuclear power

Divorce

Modern art

Abortion

Figure 10.3 The genetics of Belief
A study of thousands of identical and fraternal twins identified the approximate genetic contribution to the variation
in attitudes about diverse topics. Heritability was greatest for school prayer and property tax, and lowest for divorce,
modern art, and abortion. But notice that, in almost all cases, a person’s unique life experiences (the nonshared envi-
ronment) were far more influential than genes, especially on attitudes toward topics as unrelated as the draft, censor-
ship, and segregation (Alford, Funk, & Hibbing, 2005).

Thinking

CriTiCally

About the Genetics of

Belief