depressed than their parents, or why better diet would lead to lower
Agreeableness and Conscientiousness. It is also hard to explain whyevents that many countries share have major effects on personality traitswhereas events that are unique to individual countries seem to have solittle influence. Was the introduction of Coca Cola to the People’s Re -
public of China really more important than the Cultural Revolution in
shaping generations’ personalities?
A second, and more promising, explanation is that cultures every -
where develop similar social structures that in turn shape personality .
The cross-sectional age differences we see in Figure 4 would then reflectreal changes, but changes that are dictated by social causes. Adolescentsin every culture are expected to take adult responsibilities as they growolder, including work and raising children. It is reasonable to argue thatpeople may respond to these social pressures by becoming more seri -
ous, task oriented, and prosocial. There are several ways to test this hy-
pothesis. For example, the age at which children are supposed to begina family varies considerably across cultures. Does maturation in person-ality occur earlier in those cultures in which families are begun earlier?Within a single culture, one could conduct before-and-after studies onadolescents who do and do not begin a family (Neyer & Asendorpf,2001).
There is, however, another possibility . Perhaps cross-sectional dif-
ferences reflect intrinsic maturational changes—changes built into thehuman species in the same way that puberty and menopause are. InChapter 10 we discuss in more detail the argument that age-relatedchanges in the mean levels of personality traits are genetically deter -
mined, but it is worthwhile to mention it here. One of the major themes
of this book is that personality is largely stable in adulthood, despite themany significant events that occur. Our findings on cross-cultural agedifferences make a related point: Maturation from adolescence to adult -
hood occurs in a predictable pattern regardless of the cultural context in
which it occurs. In both cases, personality traits seem to follow theirown path, without regard to pressures of the environment. This sug -
gests that they are controlled by other forces, and genes might be re -
sponsible.
Why would people have genetic programs that cause them to be -
come more introverted and less antagonistic as they enter adulthood?
We may never know. It is clear that some men have genes that makethem go bald and most have genes that turn hair gray , but it is hard toCross-Cultural Views of Personality and Aging 95