have been associated with stress, or allostatic load, including cancer (Fitzgerald
2012 ), type 2 diabetes (van Dijk and Buwalda 2008 ), and some forms of mental
illness (Chetty et al. 2014 ; van Winkel et al. 2008 ; Mazure 1995 ).
There are marked individual differences in resilience to stress, with genetic,
epigenetic, and environmental factors at work (Zannas and West 2014 ; Zovkic et al.
2013 ). Resilient individuals have the experience to recognize whether situations are
truly threatening and have the coping skills to ameliorate the stressful nature of the
situations. Variance in resilience accounts for differential susceptibility to such
conditions as major depression and post-traumatic stress disorder (Sartor et al.
2012 ; Kessler et al. 1995 ). There is much to be learned about the causes of vari-
ability in resilience, particularly when one approaches the issue from a
cross-cultural perspective.
Just as the causes of stress are not always“bad,”such as the life changes
consequent to marriage and job promotions, the effects of stress are also not nec-
essarily bad either. Task performance is maximized when individuals are under a
given level of stress, with too much or too little stimulation leading to poorer
performance (Hermans et al. 2011 ; Segal et al. 2012 ). Some have even suggested
that exposure to acute stress may increase longevity (Epel and Lithgow 2014 ).
Stress Markers and Human Experience Across the Lifespan
There is a long history of remarkable studies of human responses to stress. Many early
studies examined people in situations that were deemed particularly stressful, such as
catecholamine responses to training as paratroopers (Bloom et al. 1963 )orcortisol
responses to engaging in actual or simulated combat situations (Bourne et al. 1968 ;
Lieberman et al. 2005 ). Classic laboratory experiments have measured biological
markers of stress in response to mental and physical work (Frankenhaeuser 1971 ;
Sluiter et al. 2000 ), electric shock (Ekman et al. 1964 ), noise (Welch and Welch 1969 ),
and bureaucratic frustrations (Glass and Singer 1972 ), among many others. These
studies have focused on whether certain predetermined conditions lead to a stress
response, what measures best detect these responses, and in some cases what the
consequences of the stress response are in terms of performance or health.
There are individual differences in the level of response to stress. These differ-
ences are largely due to differences in the cognitive appraisal that initiates the stress
response and are related to perceived lack of control and uncertainty
(Frankenhaeuser 1991 ; Wirtz et al. 2013 ). A major component of the variation has
to do with stress reactivity or the degree to which individuals respond acutely to a
stimulus, usually in a laboratory setting, defined as a stress. Individual differences in
stress reactivity are fairly stable over time, with some individuals classified as
“hyperreactors”because of their strong physiological response. There is also a
relation between chronic stress measures and laboratory-based reactivity (e.g.,
Heim et al. 2002 ; Kamarck et al. 2003 ), with those people with high levels of stress
reactivity also having high chronic stress levels. The reactivity is associated with an
128 D.E. Brown