International Balzan Foundation Luigi Luca Cavalli

Genetics and culture
Luigi Luca Cavalli-Sforza
I find it useful to call Culture the heritage of knowledge accumulating over generations,
or, we may also say, culture is what we learn from others and affects our
behavior: it is a much more general definition than the one normally used for the
word “culture” by daily newspapers, which seems to concern only films and
novels. Most animals have culture, though it is clear that humans are the most
cultural animals of all. Culture evolves according to rules which are similar to
those of biology, but the substrate is clearly very different, relying on neuronal
states and relationships, rather than on DNA structure. There are cultural
changes which are equivalent to genetic mutations, such as inventions or innovations,
but they are not as random as biological mutations. On the contrary,
they are often directed toward a specific aim. This is a major difference with biological
evolution. Another great difference is that transmission is not confined
to transmission from parents to children, but can take place, and does more often
take place, between unrelated individuals. This makes cultural change much
faster than biological change. However, there are also cultural traits which are,
in evolutionary terms, much more stable. They are often transmitted from parents
to children (what we call “vertical” transmission), and therefore imitate to
some extent biological transmission, that is known to be very stable. Children
are, to a certain extent malleable, but they also go through critical periods in
which they are especially susceptible to learning specific things, e.g. their own
language must be learned within the first three or four years of life. And the majority
of people have difficulty in learning foreign languages after adolescence.
Most cultural transmission is, however, “horizontal”, i.e. not necessarily influenced
by kinship or age difference between transmitter and transmittee. This
makes the acquisition of cultural novelties potentially very fast, and thus fast
cultural evolution favors assimilation.
What is learnt is not always necessarily favorable to survival or reproduction.
Nevertheless, one can consider culture as an adaptive mechanism that developed
out of the combined use of communication, observation of others, and
learning skills. It obviously relies on the presence of neural structures which
make this possible. Cultural change is not necessarily good or bad, though it
contributes in a significant way to determining our behavior, and, therefore, is
subject to natural selection. One can expect that this will continue to keep cultural
change adaptive, on average, even though maladaptive cultural aberrations
like crime, drugs and the like are to some extent inevitable.
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