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individual’s life experiences as well as by gene expression, and the gene expression


—affected by early developmental experiences, including maternal care—may be


epigenetically passed on over generations (Meaney 2001 ). There is mounting


evidence that stress exposure in early life leads to epigenetic changes that are


manifested throughout the rest of an individual’s life and perhaps passed down


epigenetically to later generations (Hunter 2012 ; Vaiserman 2014 ).


Studies have been carried out that have used stress measures as a tool to


understand how people react to circumstances in their daily life. These studies have


as their primary goal understanding human experience, as opposed to understanding


stress per se. This goal of understanding human experience becomes particularly


difficult when attempting to understand experiences across cultural differences.


A few examples will have to suffice to introduce this work, including research


through the life cycle.


Early experiences have a great effect on stress reactivity and chronic stress levels


throughout life, and therefore studies of children during normal activities is critical


to understanding human stress responses. A remarkable study by Mark Flinn and


coworkers surveyed hundreds of children over a 20-year period on the island of


Dominica, with over 100 salivary cortisol samples obtained from each child. The


study showed that family environment was by far the most important predictor of


stress in the children (Flinn and England 1997 ; Flinn 2009 , 2010 ). Catherine
Panter-Brick and colleagues carried out a study comparing children in Nepal who


lived in traditional rural villages,“street urchins”in Katmandu, and middle class


children in Katmandu. High cortisol levels were associated with slower growth


rates, and while, as expected, the middle class children had the lowest cortisol


levels, it was surprising that the street urchins had lower salivary cortisol levels, and


faster growth rates, than the children in traditional settings (Panter-Brick 2002 ;


Worthman and Panter-Brick 2008 ).


Adolescence is a time of stress (including for parents) as neurological devel-


opment and the transition to adulthood leads to increased experience of stress by


many teens (Arnett 1999 ; Spear 2000 ). Adolescence is a time when major shifts in


social status occur; changes in status lead to uncertainty and feelings of less control,


both of which are hallmarks of stress. Status changes comprise many of the items


on life events checklists that measure stress. When adolescents are also a part of a


population that is undergoing culture change, this stress may be heightened.


A study by McDade in Samoa has shown that adolescents faced with“status


incongruity” (where there is a disconnect between traditional and modernized


statuses) have a greater downregulation of their immune systems, as measured by


Epstein–Barr virus antibodies in blood spots, that serves as a biological marker of a


stress response (McDade 2002 ).


Studies have also examined stress in the elderly. These studies take on impor-


tance because of evidence that increased stress as measured by catecholamine


excretion is a predictor of increased risk for both heart disease and cognitive decline


(Carstensen, et al. 1995 ; Reuben et al. 2000 ; Karlamangla et al. 2005 ). In general,


older adults often respond more slowly to stress, may have an elevated response,
and take longer to recover from the stress (Ice 2005 ; Williams 2007 ). In a study of


7 Stress Biomarkers as an Objective Window on Experience 129

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