diet had changed, perhaps reflecting stress due to a greater reliance on cash crop-
ping (Yazawa et al. 2014 ). Conversely, cell phone use among the Hainan Islanders
was associated with a decrease in EBV antibodies, reflecting greater modernization
but also enhanced ability to tap into social networks, and thus greater social support.
Social support is usually viewed as a stress buffering factor (Sarason et al. 1985 );
social relationships that provide support change with modernization, but these
social relationships entail both support and obligations to provide support for
others. Among Samoan women undergoing social change, immigrants with larger
social support as measured by involvement in community associations actually
showed higher levels of stress, as measured by epinephrine excretion rates, than
those with smaller networks, while in Samoa and American Samoa the reverse was
true: greater community involvement was associated with lower epinephrine
excretion (Hanna 1998 ). Apparently the greater community involvement was
stressful to the immigrants because it entailed greater social obligations which were
generally stressful, while the support provided by involvement in community
associations buffered stress in the non-migrants.
Migrants are also exposed to very rapid culture change. In a study of young male
Afghan immigrants to Denmark, blood pressure and plasma norepinephrine levels
were higher in the immigrants than in native Danes (Asmar et al. 2013 ). There are
individual differences in the response to migration, including sex differences. For
instance, among Russian immigrants to the USA, increased mastery of the new
culture was associated with an average lowered cortisol level in men, but increased
cortisol levels in women (Nicholson et al. 2013 ). Filipino American immigrants to
Hawaii with intermediate levels of“Americanization”had significantly elevated
norepinephrine levels than immigrants with high or low levels of Americanization
(Brown 1981 , 1982 ), and immigrant Filipino American nurses and nurse’s aides
who had lived in the U.S. for a longer time period had higher norepinephrine
excretion rates during waking hours, and higher ambulatory diastolic blood pressure
during sleep, than more recent immigrants (Brown and James 2000 ). Differences in
stress levels between migrants and those who do not migrate are not just due to
stress; there are situation-specific conditions that may lead to selective migration in
which those who migrate have different characteristics than those who choose not to
migrate (Pearson and Hanna 1989 ). In general, however, increased norepinephrine
levels are found in people living in modernized environments, whether they have
migrated or not (Pearson and Hanna 1989 ; Hanna et al. 1991 ; Pearson et al. 1993 ).
Summary
People differ widely in what stimuli they consider to be stressful, and the appraisals
of threat and difficulty in coping are sometimes not conscious ones. Self-reports of
stress therefore do not capture all conditions in which people are under stress, and
individuals also differ in when it is appropriate to report that they believe they are
under stress. If stress responses can occur without being conscious of them, then
7 Stress Biomarkers as an Objective Window on Experience 133