  The quantitative description of cultural evolution is a challenging task. The
most difficult part of the problem is probably to find the appropriate
measurable quantities that can make more quantitative such evasive concepts as,
for example, dynamics of cultural movements, behavior patterns and traditions
of the people. A strategy to tackle this issue is to observe particular
features of human activities, i.e. cultural traits, such as names given to
newborns. We study the names of babies born in the United States of America
from 1910 to 2012. Our analysis shows that groups of different correlated
states naturally emerge in different epochs, and we are able to follow and
decrypt their evolution. While these groups of states are stable across many
decades, a sudden reorganization occurs in the last part of the twentieth
century. We think that this kind of quantitative analysis can be possibly
extended to other cultural traits: although databases covering more than one
century (as the one we used) are rare, the cultural evolution on shorter time
scales can be studied thanks to the fact that many human activities are usually
recorded in the present digital era.
