Emerging Trends in The Social and Behavioral Sciences

Social, Psychological, and Physiological Reactions to Stress

Item

Title

Social, Psychological, and Physiological Reactions to Stress

Author

McEwen, Bruce S.

McEwen, Craig A.

Research Area

The Individual and Society

Topic

Health and Illness

Abstract

Emerging research examines biological processes not as primary causes of social outcomes but rather as mechanisms that themselves depend on social environments. In particular, environments that produce toxic stress help shape brain development and brain and body function throughout the lifespan. Early life stress, in particular, has serious consequences for life‐long health and affects cognitive performance, emotional intelligence, and self‐regulation. Because the brain is plastic, social as well as individual behavioral interventions can alter some of these developmental paths, modifying brain function and individual life trajectories—but with increasing difficulty as children become adolescents and adults. Now reflecting the new era of “epigenetics” and a life course perspective, this new view of stress, the brain, and social environments highlights the importance of the social, psychological, and biological sciences working together to elucidate underlying mechanisms both to expand knowledge and help promote a better society.

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Identifier

etrds0311

extracted text

Social, Psychological, and
Physiological Reactions to Stress
BRUCE S. McEWEN and CRAIG A. McEWEN

Abstract
Emerging research examines biological processes not as primary causes of social outcomes but rather as mechanisms that themselves depend on social environments.
In particular, environments that produce toxic stress help shape brain development
and brain and body function throughout the lifespan. Early life stress, in particular, has serious consequences for life-long health and affects cognitive performance,
emotional intelligence, and self-regulation. Because the brain is plastic, social as well
as individual behavioral interventions can alter some of these developmental paths,
modifying brain function and individual life trajectories—but with increasing difficulty as children become adolescents and adults. Now reflecting the new era of “epigenetics” and a life course perspective, this new view of stress, the brain, and social
environments highlights the importance of the social, psychological, and biological sciences working together to elucidate underlying mechanisms both to expand
knowledge and help promote a better society.

INTRODUCTION
Emerging trends in our multidisciplinary understanding of the effects of
stress on health, behavior, and individual life trajectories have developed
in the context of long traditions of foundational research in sociology,
anthropology, and psychology and changing understandings of biology and
the brain. Biology has progressed through the DNA revolution, which early
on suggested to many in the social sciences and in the public that biologists
viewed genetic endowment as “destiny.” Moreover, the brain was long
regarded as separate from the rest of the body and stable in its architecture
laid down before birth. The connections between biology and the social
sciences were limited at best.
Yet the pioneering work of Hebb focused on the changing connections
among nerve cells in the brain in the formation of memories, and later
research by Bennett, Krech, Diamond, and Rosenzweig described the
Emerging Trends in the Social and Behavioral Sciences. Edited by Robert Scott and Stephen Kosslyn.
© 2015 John Wiley & Sons, Inc. ISBN 978-1-118-90077-2.

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

growth of the cerebral cortex induced in animals by an enriched environment. Such research began to raise awareness of the dynamic nature
of the adult as well as the developing brain in response to experiences.
Now biology has entered the era of “epigenetics” (“above the genome,”
referring to the new science of the seamless interaction between genes
and the environment and the underlying mechanisms that link them),
which is unraveling the complexities of the regulation of genetic traits
by the environment and has pointed to the enormous range of possible
outcomes of environmental/experiential influences on the brain. This work
has opened new possibilities for understanding how stress-producing
social environments and behaviors and biological mechanisms responding
to those environments interact to shape brain and body function and life
trajectories. Now is the time when the social and biological sciences can
build on one another’s insights to deepen our understanding of patterned
human behavior as well as individual variations (A and B. After most
paragraphs, one or more letters will refer the reader to bibliographic sections
organized broadly by topic at the end of the article).
CUTTING-EDGE RESEARCH, CONCEPTS, AND THEORY
A central challenge at present is to connect social science research to emerging findings in biology and neuroscience in order to understand how socially
produced adversities get “under the skin” and what social factors buffer and
protect against adverse biological effects. Social structures and relationships
influence biology in at least four different ways, especially in the early
years of life. First, social environments can create adversities—extreme
poverty, physical abuse, and unsafe and chaotic neighborhoods—that
lead to toxic stress and allostatic overload (the negative physiological
cost to the body when the active adaptation to stressors—“allostasis”—is
overused or dysregulated). These in turn shape brain structure and
function and promote a variety of diseases (http://onlinelibrary.
wiley.com/doi/10.1111/nyas.2010.1186.issue-1/issuetoc). Second, secure
and warm relationships with caregivers can protect against some of the biological consequences of adversity. Third, social interventions—well-designed
preschooling, home visiting, and classroom programming—can take advantage of the brain’s plasticity either by preventing adverse changes or, when
such changes have taken place, can promote reprogramming of those parts
of the brain that have been disrupted by adversity and toxic stress. Fourth,
social relationships as well as social conditions have epigenetic effects
related to stress responsiveness that we are just coming to understand. A
new synthesis of biology, behavior, and the social environment is made
possible by emerging concepts of toxic stress, allostasis/allostatic overload,

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and plasticity of the brain as the central organ of stress and adaptation, all
in the context of epigenetics (C, D, E—see references, which are grouped by
topic).
TOXIC STRESS AND ALLOSTATIC LOAD/OVERLOAD
We now understand that the brain and body are connected in a network of
reciprocal interactions via the autonomic, neuroendocrine, metabolic, and
immune systems that regulate each other. What happens in the brain alters
the activity of these systems and affects multiple body systems concurrently.
These systems, in turn, send signals—both neural and biochemical—back
to the brain. Normal stress responses exemplify the operation of these
interacting systems and the allostatic responses that maintain balance
among them. Normally, response to an acute stressor involves a rapid
turning on of adrenalin secretion followed by cortisol secretion, leading to
altered immune response, improved memory, and energy replenishment as
well as more efficient cardiovascular function. When the stressor is over, the
adrenalin and cortisol responses are efficiently shut off. However, when the
stress–response system remains turned on in response to chronic stressors in
the environment, this network of body systems becomes dysregulated. Toxic
stress refers to this condition and the underlying biology can be understood
in terms of allostasis and allostatic load/overload (D).
Allostasis refers to the active process of responding to challenges by activating the autonomic, neuroendocrine, metabolic, and immune systems via the
brain, the organ that perceives and responds to potential threats. Normally,
allostatic responses lead to adaptation when they are turned on and off efficiently in response to stressful events and their conclusion. However, toxic
stress leads to “allostatic load and overload” when the hormonal mediators
of the stress response continue to act on the body in ways that create “wear
and tear” (D).
Allostatic overload leads to pathophysiology (physiological imbalance,
such as hyperglycemia or chronic inflammation leading to disease) and
accelerating progression of diseases such as cardiovascular disease, diabetes,
arthritis, and depression. It also affects cognitive function negatively, in part
through its compromising effect on self-regulation and executive function.
Self-regulation involves in part the capacity to restrain impulses, anger, and
inappropriate behavior. Executive function is an aspect of self-regulation
involving mobilization of short-term memory, capacity to sequence and shift
tasks, and focus attention—all important to planning, thinking and solving
problems. These compromised capacities in turn affect social behavior and
school as well as later occupational success. Thus, the toll taken by allostatic
overload is considerable (C, D).

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

Stressful life experiences produce toxic stress and allostatic load
(http://developingchild.harvard.edu/index.php/activities/council/).
Early life experiences are biologically embedded, in the sense that they can
have long-lasting effects on brain function and on brain–body interactions
that strongly influence life course trajectories. The Adverse Childhood
Experiences (ACE) study led by Drs Vincent Fellitti and Robert Anda
revealed the long-lasting consequences for physical and mental health of
events early in a child’s life. An ACE score derives from counts of adversities
in childhood—including parental divorce, family member incarcerated,
alcohol or drug abuse or depression in family, harsh language, and physical
or sexual abuse. It is important to note that both mental health problems
such as depression; substance abuse and antisocial behavior; and physical
health disorders such as cardiovascular disease, chronic obstructive pulmonary disorder (COPD), and diabetes show a dose-dependent effect of
the ACE score (G). For the brain, a child growing up over a 10-year period
with a depressed mother will have an enlarged amygdala, a brain region
that mediates anxiety and fear. And, in addition to ACE, which occur at all
socioeconomic levels, long-term poverty adds a powerful additional stamp,
impairing the development of the prefrontal cortex and of self-regulatory
behavior through toxic stress, produced in part by chaotic and crowded
homes and dangerous neighborhoods. Alienation and social isolation
can also have devastating effects upon well-being, and both hostility and
loneliness are themselves severe stressors and contribute to allostatic load
(C, D G).
Importantly, supportive social relationships—especially from caregivers
in early childhood—help protect against allostatic overload in the face of
sustained environmental stressors (http://developingchild.harvard.edu/
resources/reports_and_working_papers/foundations-of-lifelong-health/).
Throughout the lifespan and particularly later in life, eudaimonic well-being
(feeling connected to a deeper purpose) is associated with lower allostatic
load and higher cognitive and physical function, as well as lower incidence
of dementia in the elderly when compared with hedonic well-being, (feeling
gratification from immediately pleasurable experiences) (E).
THE BRAIN’S PLASTICITY
Over the past several decades, we have become increasingly aware that the
structure and function of the brain are malleable as a result of experiences
in the physical and social environment, including the nature of social interactions, during development and in adult life. Building upon the work of
Hebb and Bennett, Krech, Diamond, and Rosenzweig, we now understand
the continuous turnover of at least some of the synaptic connections in the

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brain modulated by experience and mediated, in part, by the daily fluctuations of cortisol, otherwise known as a “stress” hormone but having many
other important functions. Moreover, limited development of new neurons
takes place in several parts of the brain, continues throughout adult life, and
can be altered both by experiences and by hormones (A).
Stressful experiences impair this plasticity, however, and cause reversible
changes in the neural architecture of healthy brains that promote vigilance
in the face of danger along with changes in gene expression reflective of
cumulative experiences. When these changes persist after danger passes, the
altered brain architecture can lead to anxiety and other mood disorders. Yet,
regular physical activity enhances plasticity and stimulates neuron development in and increases in the volume of the hippocampus while improving
memory and executive function; intense learning also changes brain architecture. In contrast, diabetes, which has increased in incidence in part as a
result of poverty and early life adversity, leads to impaired brain architecture even in teenagers, along with impaired cognitive function and increased
risk for Alzheimer’s disease later in life. Furthermore, perceptions of inequality in adults as a result of socioeconomic differences predict health status and
have correlates in aspects of brain structure and function, including impaired
white matter (the “insulation” of the brain) (A, D).
As we have seen, plasticity means that early childhood experiences affect
brain development. For example, language processing capacity and ability as
well as emotional intelligence grow in early “serve and return” interactions
between infants and caregivers (http://developingchild.harvard.edu/index.
php/activities/council/). When parents coo or gesture in response to their
infants or talk with their children, they are engaging in serve and return
interactions that play a key role in building brain architecture. One
example of serve and return involves linguistic interactions between
parents and caregivers. The pioneering research of Hart and Risley
and subsequent studies have shown that children from poor families
are likely to hear far fewer words than their counterparts in professional families with consequences for both their vocabularies and the
linguistic capacities of their brains. Ongoing research with recorders
that gauge volume of linguistic interaction between parents and children suggests that helpful monitoring and feedback increases verbal
interaction significantly. Serve and return interactions not only promote
language and cognitive development but are a key to strong attachments
with caregivers and increased capacity for self-regulation and empathy
(http://developingchild.harvard.edu/index.php/activities/council/) (C).
The implications of plasticity are two-sided. On the one hand, as we have
seen, adversities and toxic stress can impair brain architecture, especially

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

early in life. On the other hand, brain growth in response to positive interactions with caregivers builds strong brain architecture. Programs such as
the Nurse Family Partnership (http://www.nursefamilypartnership.org/)
intervene early on to build the positive and reduce the negative experiences
of early childhood. Evidence indicates home visiting has beneficial effects
by reducing childhood adversities and increasing protective relationships
through support and education of parents starting even before the birth of
the child. Later social interventions can also “reprogram” the brain in ways
that help to overcome the effects of early adversities. Longitudinal studies of
high-quality preschool programs in Michigan, North Carolina, and Illinois
provide evidence that early interventions with at-risk children can have
powerful long-lasting effects. For example, long-term follow-up of the
Highscope Perry School’s two-year preschool program for an experimental
group of 3- to 4-year-olds project has shown multiple benefits, including
higher rates of school completion, higher income for adults, and reduced
arrests (http://www.highscope.org/Content.asp?ContentId=219). Moreover, such high-quality early childhood programs as the Abecedarian Project
in North Carolina have been shown not only to have substantial benefits in
reducing crime, raising earnings, and promoting education but also significantly lower prevalence of risk factors for cardiovascular and metabolic diseases in the mid-30s, especially among males. The website of the National Scientific Council on the Developing Child is a rich source of information on this
topic (http://developingchild.harvard.edu/index.php/activities/council/)
(E).
GENETIC VARIANTS MATTER—ORCHID AND DANDELION CHILDREN
Recent research on children as well as studies using animal models also
makes us increasingly aware that commonly occurring genetic variants (alleles) make individuals differentially responsive to their environments. The
so-called “context-sensitive alleles” increase sensitivity to both positive and
negative experiences. As a result, children with such alleles do better than
average in functioning in positive school environments, while, in chaotic,
more stressful and less nurturing environments, such context-sensitive
children (“orchid children”) will do worse than the so-called “dandelion
children” who are far less responsive to context. It is not clear yet whether
“orchid” individuals might actually do better later in life in responding to
therapeutic interventions because of their context sensitivity and, possibly,
their greater capacity for plasticity via epigenetic mechanisms, compared to
“dandelion” individuals (B).

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EPIGENETICS
Emerging knowledge of epigenetics further reveals the power of social
environments, experiences, and behavior to shape and reshape biology. “Epigenetics” refers to the seamless and continuous interaction between environmental and experiential factors and the genetic constitution of an individual.
Epigenetic mechanisms operate via folding and unfolding of the DNA double helix to repress or expose genes and involving modifications of DNA by
methylation of the cytosine base as well as through the operation of so-called
“non-coding” RNAs that modify how the primary RNA messages are processed and encoded into proteins. These mechanisms operate throughout the
life course and offer opportunities to change brain and body function at any
age, although making such changes becomes harder after the critical or sensitive developmental periods have past. Epigenetics emphasizes plasticity and
malleability, which can be observed at many different levels and not only at
the level of gene regulation. For example, environmentally regulated changes
can occur in neural architecture, involving limited neurogenesis and also the
turnover of synaptic connections and shrinkage and expansion of neuronal
dendritic trees. Yet, ultimately everything that happens to the cells of our
body influences the expression of our genetic code, and the modern science
of “epigenetics” has started to uncover multiple mechanisms that provide
many permutations and combinations with many possible outcomes.
Particularly noteworthy is the fact that genetically identical individuals can
become different owing to epigenetic effects of nonshared experiences (B).
Recent research by Meaney demonstrates the powerful effects that social
relationships can have on gene expression related to the experience of stress.
This research shows that the extent to which rat mothers lick and groom
their nursing pups affects whether or not at least the expression of one of
the pup’s genes is modified. When this epigenetic change takes place as a
result of intense licking and grooming, the pups will be better able to limit
their reactions to high-stress situations. This epigenetic change (with no
alteration in the DNA) then is later passed on by the pup to its offspring.
Emerging evidence from Chen, Miller, and colleagues about parallel epigenetic changes in human infants resulting from adversities suggests that
they affect genes that react to stress in ways affecting blood pressure and
heart rate. Over the life course, the result is a body with greater sensitivity
to stress and inflammation (B).
SUMMARY
Recent research and theorizing focus on biological stress processes in the
brain and body, in continuous interaction with social as well as physical environments and their effects on the health and life chances of individuals and

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throughout the life course. As a result, biological stress mechanisms can reinforce broad social patterns of inequality—for example, increasing the chances
that poor children will be poor as adults and the likelihood that illnesses such
as depression, obesity, diabetes, and cardiovascular disease will occur more
frequently among the poor and working class. On the other hand, the plasticity of the brain and responsiveness of the body to the environment open up
opportunities through evidence-based interventions such as home visiting,
high-quality preschool education, and changes in social supports for parents to prevent or overcome early disadvantages and build the foundations
for productive and satisfying lives. The research also implies that reducing
the sources of toxic stress by interventions such as lowering poverty, supporting neighborhood development, and providing affordable, high-quality
child care can affect developing brains and provide long-term dividends in
health and well-being.
KEY ISSUES FOR FUTURE RESEARCH
This emerging view of closely interlinked biology, behavior, and social structures and relationships has many implications for both research and interventions. As a result, it is vital that there be both research collaborations across
disciplines and organized attention to communicating research results to policy makers. The research issues include the following:

•

•

•

Research to find ways to open “windows of plasticity” so that behavioral and social interventions can promote beneficial change even after
early adversity has occurred. We know that regular physical activity is
one way to do this, but research could open other ways to open those
windows (F).
Research to refine our understanding of which social and environmental conditions produce toxic stress and under what conditions. Current
research examines a wide array of adversities—environmental, interpersonal, social structural—but without either an organizing theory or
systematic evidence using consistent variables to indicate which adversities created by poverty matter most for toxic stress.
Enhance understanding of protective factors and the social structures
and resources that support them. We know that warm, supportive relationships and strong parent–child bonding protect against toxic stressors. But we know far less well how and why the availability of such
relationships varies across families and groups and what social interventions might be most effective in building those relationships and at
what ages they can be effective.

Social, Psychological, and Physiological Reactions to Stress

•

•

•

•

9

Research to elaborate our understanding of the epigenetic basis of context sensitivity and the ways that they influence the responses of infants
and children to their social environments. This research is in its early
stages. We need to know not only the early developmental implications
of context sensitivity and insensitivity but also their potential contributions to efforts to “reprogram” the plastic brain through later school
programs or therapeutic interventions.
Reorienting research on health, social and cognitive ability, social
mobility, and schooling to recognize the entire life course—especially
including early childhood. We are beginning to recognize the importance of experiences over the entire life course (the “life course
development model” by Halfon and colleagues) in the emerging
era of “epigenetics” and brain plasticity and brain–body reciprocal
interactions. In the domain of health, this has led to what is now called
“integrative medicine” to prevent as well as treat disorders in an era
when health care costs are increasing and people are living longer (B).
Systematic evaluation research on interventions to reduce toxic stress or
to overcome its effects on brain and body. In order to arrange our society
in order to realize human potential, research is needed to assess interventions such as high quality child care, parent education, income supports on children’s development, and their subsequent trajectories. This
research ideally should involve scholars of many disciplines in order to
gauge the nature and implementation of the interventions, their impact
on brain and body development, and school behavior and performance,
among other variables.
Research to assess macro-level social interventions. Which macrolevel
interventions, if any (such as widely available publicly supported child
care, universal family leave, income supports) reduce childhood adversity and toxic stress and improve developmental outcomes? Comparative international research or studies comparing localities or states with
differing social policies can help answer these questions. At the societal
level, the most important top-down interventions are the policies of government and the private sector that not only improve education but also
allow people to make choices that improve their chances for a healthy
life. For example, the Acheson report of the British Government in 1998
recognized that no public policy of virtually any kind should be enacted
without considering the implications for the health of all citizens. In
addition, private sectors policies that encourage healthy lifestyle practices among their employees are likely to gain reduced health insurance
costs and possibly a more loyal workforce (E).

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FURTHER READING
A. Brain plasticity and role in memory, self regulation and mood
Bennett, E., Diamond, M., Krech, D., & Rosenzweig, M. (1964). Chemical and anatomical plasticity of brain. Science, 146, 610–619.
Gould, E. (2007). How widespread is adult neurogenesis in mammals? Nature
Reviews Neuroscience, 8, 481–488.
Gray, J. D., Rubin, T. G., Hunter, R. G., & McEwen, B. S. (2013). Hippocampal gene
expression changes underlying stress sensitization and recovery. Molecular Psychiatry, 19, 1171–1178.
Hebb, D. O. (1949). The organization of behavior; a neuropsychological theory. New York,
NY: Wiley.
Liston, C., Cichon, J. M., Jeanneteau, F., Jia, Z., Chao, M. V., & Gan, W. B. (2013). Circadian glucocorticoid oscillations promote learning-dependent synapse formation
and maintenance. Nature Neurosci, 16, 698–705.
McEwen, B. S. (1999). Stress and hippocampal plasticity. Annual Review of Neuroscience, 22, 105–122.
McEwen, B. S., & Morrison, J. H. (2013). The brain on stress: Vulnerability and plasticity of the prefrontal cortex over the life course. Neuron, 79, 16–29.
Roozendaal, B., McEwen, B. S., & Chattarji, S. (2009). Stress, memory and the amygdala. Nature Review of Neuroscience, 10, 423–433.
B. Epigenetics and individual differences
Boyce, W. T., & Ellis, B. J. (2005). Biological sensitivity to context: I. An evolutionarydevelopmental theory of the origins and functions of stress reactivity. Development
and Psychopathology, 17, 271–301.
Chen, E., Miller, G. E., Kobor, M. S., & Cole, S. W. (2011). Maternal warmth buffers
the effects of low early-life socioeconomic status on pro-inflammatory signaling
in adulthood. Molecular Psychiatry, 16, 729–737.
Fraga, M.F., E. Ballestar, M.F. Paz, S. Ropero, F. Setien, M.L. Ballestar … , M. Esteller.
2005. Epigenetic differences arise during the lifetime of monozygotic twins.
Proceedings of the National Academy of Sciences of the United States of America
102:10604–10609.
Halfon, N., Larson, K., Lu, M., Tullis, E., & Russ, S. (2014). Lifecourse health development: Past, present and future. Maternal and Child Health Journal, 18, 344–365.
Meaney, M. J. (2010). Epigenetics and the biological definition of gene × environment
interactions. Child Development, 81(1), 41–79.
Miller, G. E., & Chen, E. (2010). Harsh family climate in early life presages the emergence of a proinflammatory phenotype in adolescence. Psychological Science, 21,
848–856.
Obradovic, J., Bush, N. R., Stamperdahl, J., Adler, N. E., & Boyce, W. T. (2010). Biological sensitivity to context: The interactive effects of stress reactivity and family
adversity on socioemotional behavior and school readiness. Child Development, 81,
270–289.

Social, Psychological, and Physiological Reactions to Stress

11

Szyf, M., McGowan, P., & Meaney, M. J. (2008). The social environment and the
epigenome. Environmental and Molecular Mutagenesis, 49, 46–60.
C. Inequality in health, the brain and cognitive function
Acheson, S. D. (1998). Independent inquiry into inequalities in health report. London,
England: The Stationary Office.
Drewnowski, A., & Specter, S. E. (2004). Poverty and obesity: The role of energy density and energy costs. Am. J. Clin. Nutr., 79, 6–16.
Duncan, G. J., Magnuson, K., Kalil, A., & Ziol-Guest, K. (2012). The importance of
early childhood poverty. Social Indicators Research, 108(1), 87–98.
Duncan, G. J., Ziol-Guest, K. M., & Kalil, A. (2010). Early-childhood poverty and
adult attainment, behavior, and health. Child Development, 81(1), 306–325.
Evans, G. W., & Rosenbaum, J. (2008). Self-regulation and the income-achievement
gap. Early Childhood Research Quarterly, 23(4), 504–514. doi:10.1016/j.ecresq.2008.
07.002
Evans, G. W., & Schamberg, M. A. (2009). Childhood poverty, chronic stress, and
adult working memory. Proceedings of the National Academy of Sciences of the United
States of America, 106(16), 6545–6549.
Evans, G. W., & Wachs, T. D. (Eds.) (2010). Chaos and its influence on children’s development: An ecological perspective. Washington, DC: American Psychological Association.
Fernald, A., Marchman, V. A., & Weisleder, A. (2013). SES differences in language
processing skill and vocabulary are evident at 18 months. Developmental Science,
16(2), 234–248. doi:10.1111/desc.12019
Hart, B., & Risley, T. R. (1995). Meaningful differences in the everyday experience of young
American children. Baltimore, MD: Brookes Publishing Company.
Hackman, D. A., Farah, M. J., & Meaney, M. J. (2010). Socioeconomic status and the
brain: Mechanistic insights from human and animal research. Nature Reviews Neuroscience, 11, 651–659.
Kawachi, I., Kennedy, B. P., Lochner, K., & Prothrow-Stith, D. (1997). Social capital,
income inequality, and mortality. American Journal of Public Health, 87, 1491–1498.
Kim, P., Evans, G. W., Angstadt, M., Ho, S. S., Sripada, C. S., Swain, J. E., … , Phan, K.
L. (2013). Effects of childhood poverty and chronic stress on emotion regulatory
brain function in adulthood. Proceedings of the National Academy of Sciences of the
United States of America 110:18442–18447.
Sampson, R. J., Raudenbush, S. W., & Earls, F. (1997). Neighborhoods and violent
crime: A multilevel study of collective effects. Science, 277, 918–924.
D. Toxic Stress, Allostatic load and overload—impact on brain and body
Hawkley, L. C., & Cacioppo, J. T. (2010). Loneliness matters: A theoretical and empirical review of consequences and mechanisms. Annals of Behavioral Medicine, 40,
218–227.

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

Juster, R. P., McEwen, B. S., & Lupien, S. J. (2010). Allostatic load biomarkers
of chronic stress and impact on health and cognition. Neurosci & Biobehavioral
Reviews, 35, 2–16.
McEwen, B. S. (1998). Protective and damaging effects of stress mediators. The New
England Journal of Medicine, 338, 171–179.
McEwen, B. S. (2006). Protective and damaging effects of stress mediators: Central
role of the brain. Dialogues in Clinical Neuroscience: Stress, 8, 367–381.
McEwen, B. S., & Wingfield, J. C. (2003). The concept of allostasis in biology and
biomedicine. Hormones & Behavior, 43, 2–15.
Verstynen, T. D., Weinstein, A., Erickson, K. I., Sheu, L. K., Marsland, A. L., & Gianaros, P. J. (2013). Competing physiological pathways link individual differences
in weight and abdominal adiposity to white matter microstructure. Neuroimage,
79, 129–137.
Yau, P. L., Castro, M. G., Tagani, A., Tsui, W. H., & Convit, A. (2012). Obesity and
metabolic syndrome and functional and structural brain impairments in adolescence. Pediatrics, 130, e856–e864.
E. Social interventions
Aldana, S. G. (2001). Financial impact of health promotion programs: A comprehensive review of the literature. American Journal of Health Promotion, 15, 296–320.
Boyle, P. A., Buchman, A. S., Barnes, L. L., & Bennett, D. A. (2010). Effect of a purpose
in life on risk of incident Alzheimer disease and mild cognitive impairment in
community-dwelling older persons. Archives of General Psychiatry, 67, 304–310.
Campbell, F., Conti, G., Heckman, J. J., Moon, S. H., Pinto, R., Pungello, E., & Pan, Y.
(2014). Early childhood investments substantially boost adult health. Science, 343,
1478–1485.
Carlson, M. C., Erickson, K. I., Kramer, A. F., Voss, M. W., Bolea, N., … , Fried, L.
P. (2009). Evidence for neurocognitive plasticity in at-risk older adults: The experience corps program. The Journals of Gerontology Series A: Biological Sciences and
Medical Sciences 64: 1275–1282.
Duncan, G. J., & Sojourner, A. J. (2013). Can intensive early childhood intervention programs eliminate income-based cognitive and achievement gaps? Journal
of Human Resources, 48(4), 945–968.
Suskind, D., Leffel, K. R., Hernandez, M. W., Sapolich, S. G., Suskind, E., Kirkham,
E., & Meehan, P. (2013). An exploratory study of ‘quantitative linguistic feedback’:
Effect of LENA feedback on adult language production. Communication Disorders
Quarterly, 34(4), 199–209.
F. Physical activity and learning effects on brain
Draganski, B., Gaser, C., Kempermann, G., Kuhn, H. G., Winkler, J., Buchel, C., &
May, A. (2006). Temporal and spatial dynamics of brain structure changes during
extensive learning. Journal of Neuroscience, 26, 6314–6317.

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Erickson, K. I., Voss, M. W., Prakash, R. S., Basak, C., Szabo, A., Chaddock,
L., … , Kramer, A. F.. (2011). Exercise training increases size of hippocampus and
improves memory. Proceedings of the National Academy of Sciences of the United States
of America 108: 3017–3022.
G. Effects of early life adversity and lifecourse developmental perspective
Anda, R. F., Butchart, A., Felitti, V. J., & Brown, D. W. (2010). Building a framework for
global surveillance of the public health implications of adverse childhood experiences. American Journal of Preventive Medicine, 39, 93–98.
Evans, G. W., Li, D., & Whipple, S. S. (2013). Cumulative risk and child development.
Psychological Bulletin, 139(6), 1342–1396.
Felitti, V. J., Anda, R. F., Nordenberg, D., Williamson, D. F., Spitz, A. M., Edwards,
V., … , Marks, J. S. (1998). Relationship of childhood abuse and household dysfunction to many of the leading causes of death in adults. The adverse childhood
experiences (ACE) study. American Journal of Preventive Medicine. 14: 245–258.
Lupien, S. J., Parent, S., Evans, A. C., Tremblay, R. E., Zelazo, P. D., Corbo,
V., … , Seguin, J. R. (2011). Larger amygdala but no change in hippocampal volume
in 10-year-old children exposed to maternal depressive symptomatology since
birth. Proceedings of the National Academy of Sciences of the United States of America
108: 14324–14329.

BRUCE S. McEWEN SHORT BIOGRAPHY
Bruce S. McEwen obtained his PhD in Cell Biology in 1964 from the Rockefeller University. He is a member of the US National Academy of Sciences,
the Institute of Medicine, and the American Academy of Arts and Sciences.
He served as President of the Society for Neuroscience in 1997–1998. As a
neuroscientist and neuroendocrinologist, McEwen studies environmentally
regulated, variable gene expression in the brain, mediated by circulating
steroid hormones and endogenous neurotransmitters in relation to brain
sexual differentiation and the actions of sex and stress hormones on the
adult brain, in particular related to structural and functional plasticity via
epigenetic mechanisms. His laboratory discovered adrenal steroid receptors
in the hippocampus in 1968. His laboratory combines molecular, anatomical,
pharmacological, physiological, and behavioral methodologies and relates
their findings to human clinical information. His current research focuses on
stress effects on amygdala and prefrontal cortex, as well as the hippocampus,
and his laboratory also investigates sex hormone effects and sex differences
in these brain regions involved in cognitive function and mood regulation.
He served on the MacArthur Foundation Research Network on Socioeconomic Status and Health, in which he has helped to reformulate concepts
and measurements related to stress and stress hormones in the context of

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

human societies, which led to the concept of “allostatic load and overload”
that describes the wear and tear on the body and brain from chronic stress
and related life style behaviors that lead to dysregulation of physiological
stress pathways that are normally protective. He is also a member of the
National Council on the Developing Child, which focuses on biological
embedding of early life experiences and promoting healthy brain development. He is the coauthor of a book with science writer, Elizabeth Lasley, for
a lay audience called “The End of Stress as We Know It,” published in 2002,
and “The Hostage Brain” with science writer, the late Harold M. Schmeck,
Jr., published in 1994, both of which are now available as eBooks.
Web: http://www.rockefeller.edu/labheads/mcewen/mcewen-lab.php
CRAIG A. McEWEN SHORT BIOGRAPHY
Craig A. McEwen is Daniel B. Fayerweather Professor of Political Economy and Sociology Emeritus at Bowdoin College where he taught from
1975 to 2012. A 1967 graduate of Oberlin College, he earned his PhD in
sociology at Harvard University in 1975 after teaching 4 years at Morgan
State College (now University). Over the past decade he has become deeply
involved in community initiatives addressing poverty and early childhood
development with the United Way of Mid Coast Maine particularly. For
example, he chairs the implementation committee for a home visiting
initiative that will expand those resources in the region. At Bowdoin he
helped to found the Center for the Common Good and then served as
Senior Faculty Fellow there for 5 years supporting student involvement
in community service and community-based courses. He developed and
taught a course that involved students in doing research with and for local
agencies providing services to low income clients. His scholarly interests
have followed this teaching and community engagement and now focus
particularly on the impact of poverty on child development. His early
research and writing examined community corrections in comparison in a
book, Designing Correctional Organizations for Youths. Over the next 30 years
his research and commentary focused largely on the legal profession, courts
and mediation programs—small claims, community, corporate, family and
general civil—and has been published widely in law reviews, social science
journals and professional magazines. He is coauthor of the treatise Mediation:
Law, Policy, Practice (with Sarah Cole, Nancy Rogers, James Coben, and Peter
N. Thompson). He also coauthored with Lynn Mather and Richard Maiman
an empirical study of Divorce Lawyers at Work: Varieties of Professionalism in
Practice, and with Nancy Rogers, Robert Bordone and Frank Sander wrote
Designing Systems and Processes for Managing Disputes. At Bowdoin he served
as Dean for Academic Affairs from 1999 to 2006.

Social, Psychological, and Physiological Reactions to Stress

15

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Social, Psychological, and
Physiological Reactions to Stress
BRUCE S. McEWEN and CRAIG A. McEWEN

Abstract
Emerging research examines biological processes not as primary causes of social outcomes but rather as mechanisms that themselves depend on social environments.
In particular, environments that produce toxic stress help shape brain development
and brain and body function throughout the lifespan. Early life stress, in particular, has serious consequences for life-long health and affects cognitive performance,
emotional intelligence, and self-regulation. Because the brain is plastic, social as well
as individual behavioral interventions can alter some of these developmental paths,
modifying brain function and individual life trajectories—but with increasing difficulty as children become adolescents and adults. Now reflecting the new era of “epigenetics” and a life course perspective, this new view of stress, the brain, and social
environments highlights the importance of the social, psychological, and biological sciences working together to elucidate underlying mechanisms both to expand
knowledge and help promote a better society.

INTRODUCTION
Emerging trends in our multidisciplinary understanding of the effects of
stress on health, behavior, and individual life trajectories have developed
in the context of long traditions of foundational research in sociology,
anthropology, and psychology and changing understandings of biology and
the brain. Biology has progressed through the DNA revolution, which early
on suggested to many in the social sciences and in the public that biologists
viewed genetic endowment as “destiny.” Moreover, the brain was long
regarded as separate from the rest of the body and stable in its architecture
laid down before birth. The connections between biology and the social
sciences were limited at best.
Yet the pioneering work of Hebb focused on the changing connections
among nerve cells in the brain in the formation of memories, and later
research by Bennett, Krech, Diamond, and Rosenzweig described the
Emerging Trends in the Social and Behavioral Sciences. Edited by Robert Scott and Stephen Kosslyn.
© 2015 John Wiley & Sons, Inc. ISBN 978-1-118-90077-2.

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

growth of the cerebral cortex induced in animals by an enriched environment. Such research began to raise awareness of the dynamic nature
of the adult as well as the developing brain in response to experiences.
Now biology has entered the era of “epigenetics” (“above the genome,”
referring to the new science of the seamless interaction between genes
and the environment and the underlying mechanisms that link them),
which is unraveling the complexities of the regulation of genetic traits
by the environment and has pointed to the enormous range of possible
outcomes of environmental/experiential influences on the brain. This work
has opened new possibilities for understanding how stress-producing
social environments and behaviors and biological mechanisms responding
to those environments interact to shape brain and body function and life
trajectories. Now is the time when the social and biological sciences can
build on one another’s insights to deepen our understanding of patterned
human behavior as well as individual variations (A and B. After most
paragraphs, one or more letters will refer the reader to bibliographic sections
organized broadly by topic at the end of the article).
CUTTING-EDGE RESEARCH, CONCEPTS, AND THEORY
A central challenge at present is to connect social science research to emerging findings in biology and neuroscience in order to understand how socially
produced adversities get “under the skin” and what social factors buffer and
protect against adverse biological effects. Social structures and relationships
influence biology in at least four different ways, especially in the early
years of life. First, social environments can create adversities—extreme
poverty, physical abuse, and unsafe and chaotic neighborhoods—that
lead to toxic stress and allostatic overload (the negative physiological
cost to the body when the active adaptation to stressors—“allostasis”—is
overused or dysregulated). These in turn shape brain structure and
function and promote a variety of diseases (http://onlinelibrary.
wiley.com/doi/10.1111/nyas.2010.1186.issue-1/issuetoc). Second, secure
and warm relationships with caregivers can protect against some of the biological consequences of adversity. Third, social interventions—well-designed
preschooling, home visiting, and classroom programming—can take advantage of the brain’s plasticity either by preventing adverse changes or, when
such changes have taken place, can promote reprogramming of those parts
of the brain that have been disrupted by adversity and toxic stress. Fourth,
social relationships as well as social conditions have epigenetic effects
related to stress responsiveness that we are just coming to understand. A
new synthesis of biology, behavior, and the social environment is made
possible by emerging concepts of toxic stress, allostasis/allostatic overload,

Social, Psychological, and Physiological Reactions to Stress

3

and plasticity of the brain as the central organ of stress and adaptation, all
in the context of epigenetics (C, D, E—see references, which are grouped by
topic).
TOXIC STRESS AND ALLOSTATIC LOAD/OVERLOAD
We now understand that the brain and body are connected in a network of
reciprocal interactions via the autonomic, neuroendocrine, metabolic, and
immune systems that regulate each other. What happens in the brain alters
the activity of these systems and affects multiple body systems concurrently.
These systems, in turn, send signals—both neural and biochemical—back
to the brain. Normal stress responses exemplify the operation of these
interacting systems and the allostatic responses that maintain balance
among them. Normally, response to an acute stressor involves a rapid
turning on of adrenalin secretion followed by cortisol secretion, leading to
altered immune response, improved memory, and energy replenishment as
well as more efficient cardiovascular function. When the stressor is over, the
adrenalin and cortisol responses are efficiently shut off. However, when the
stress–response system remains turned on in response to chronic stressors in
the environment, this network of body systems becomes dysregulated. Toxic
stress refers to this condition and the underlying biology can be understood
in terms of allostasis and allostatic load/overload (D).
Allostasis refers to the active process of responding to challenges by activating the autonomic, neuroendocrine, metabolic, and immune systems via the
brain, the organ that perceives and responds to potential threats. Normally,
allostatic responses lead to adaptation when they are turned on and off efficiently in response to stressful events and their conclusion. However, toxic
stress leads to “allostatic load and overload” when the hormonal mediators
of the stress response continue to act on the body in ways that create “wear
and tear” (D).
Allostatic overload leads to pathophysiology (physiological imbalance,
such as hyperglycemia or chronic inflammation leading to disease) and
accelerating progression of diseases such as cardiovascular disease, diabetes,
arthritis, and depression. It also affects cognitive function negatively, in part
through its compromising effect on self-regulation and executive function.
Self-regulation involves in part the capacity to restrain impulses, anger, and
inappropriate behavior. Executive function is an aspect of self-regulation
involving mobilization of short-term memory, capacity to sequence and shift
tasks, and focus attention—all important to planning, thinking and solving
problems. These compromised capacities in turn affect social behavior and
school as well as later occupational success. Thus, the toll taken by allostatic
overload is considerable (C, D).

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

Stressful life experiences produce toxic stress and allostatic load
(http://developingchild.harvard.edu/index.php/activities/council/).
Early life experiences are biologically embedded, in the sense that they can
have long-lasting effects on brain function and on brain–body interactions
that strongly influence life course trajectories. The Adverse Childhood
Experiences (ACE) study led by Drs Vincent Fellitti and Robert Anda
revealed the long-lasting consequences for physical and mental health of
events early in a child’s life. An ACE score derives from counts of adversities
in childhood—including parental divorce, family member incarcerated,
alcohol or drug abuse or depression in family, harsh language, and physical
or sexual abuse. It is important to note that both mental health problems
such as depression; substance abuse and antisocial behavior; and physical
health disorders such as cardiovascular disease, chronic obstructive pulmonary disorder (COPD), and diabetes show a dose-dependent effect of
the ACE score (G). For the brain, a child growing up over a 10-year period
with a depressed mother will have an enlarged amygdala, a brain region
that mediates anxiety and fear. And, in addition to ACE, which occur at all
socioeconomic levels, long-term poverty adds a powerful additional stamp,
impairing the development of the prefrontal cortex and of self-regulatory
behavior through toxic stress, produced in part by chaotic and crowded
homes and dangerous neighborhoods. Alienation and social isolation
can also have devastating effects upon well-being, and both hostility and
loneliness are themselves severe stressors and contribute to allostatic load
(C, D G).
Importantly, supportive social relationships—especially from caregivers
in early childhood—help protect against allostatic overload in the face of
sustained environmental stressors (http://developingchild.harvard.edu/
resources/reports_and_working_papers/foundations-of-lifelong-health/).
Throughout the lifespan and particularly later in life, eudaimonic well-being
(feeling connected to a deeper purpose) is associated with lower allostatic
load and higher cognitive and physical function, as well as lower incidence
of dementia in the elderly when compared with hedonic well-being, (feeling
gratification from immediately pleasurable experiences) (E).
THE BRAIN’S PLASTICITY
Over the past several decades, we have become increasingly aware that the
structure and function of the brain are malleable as a result of experiences
in the physical and social environment, including the nature of social interactions, during development and in adult life. Building upon the work of
Hebb and Bennett, Krech, Diamond, and Rosenzweig, we now understand
the continuous turnover of at least some of the synaptic connections in the

Social, Psychological, and Physiological Reactions to Stress

5

brain modulated by experience and mediated, in part, by the daily fluctuations of cortisol, otherwise known as a “stress” hormone but having many
other important functions. Moreover, limited development of new neurons
takes place in several parts of the brain, continues throughout adult life, and
can be altered both by experiences and by hormones (A).
Stressful experiences impair this plasticity, however, and cause reversible
changes in the neural architecture of healthy brains that promote vigilance
in the face of danger along with changes in gene expression reflective of
cumulative experiences. When these changes persist after danger passes, the
altered brain architecture can lead to anxiety and other mood disorders. Yet,
regular physical activity enhances plasticity and stimulates neuron development in and increases in the volume of the hippocampus while improving
memory and executive function; intense learning also changes brain architecture. In contrast, diabetes, which has increased in incidence in part as a
result of poverty and early life adversity, leads to impaired brain architecture even in teenagers, along with impaired cognitive function and increased
risk for Alzheimer’s disease later in life. Furthermore, perceptions of inequality in adults as a result of socioeconomic differences predict health status and
have correlates in aspects of brain structure and function, including impaired
white matter (the “insulation” of the brain) (A, D).
As we have seen, plasticity means that early childhood experiences affect
brain development. For example, language processing capacity and ability as
well as emotional intelligence grow in early “serve and return” interactions
between infants and caregivers (http://developingchild.harvard.edu/index.
php/activities/council/). When parents coo or gesture in response to their
infants or talk with their children, they are engaging in serve and return
interactions that play a key role in building brain architecture. One
example of serve and return involves linguistic interactions between
parents and caregivers. The pioneering research of Hart and Risley
and subsequent studies have shown that children from poor families
are likely to hear far fewer words than their counterparts in professional families with consequences for both their vocabularies and the
linguistic capacities of their brains. Ongoing research with recorders
that gauge volume of linguistic interaction between parents and children suggests that helpful monitoring and feedback increases verbal
interaction significantly. Serve and return interactions not only promote
language and cognitive development but are a key to strong attachments
with caregivers and increased capacity for self-regulation and empathy
(http://developingchild.harvard.edu/index.php/activities/council/) (C).
The implications of plasticity are two-sided. On the one hand, as we have
seen, adversities and toxic stress can impair brain architecture, especially

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

early in life. On the other hand, brain growth in response to positive interactions with caregivers builds strong brain architecture. Programs such as
the Nurse Family Partnership (http://www.nursefamilypartnership.org/)
intervene early on to build the positive and reduce the negative experiences
of early childhood. Evidence indicates home visiting has beneficial effects
by reducing childhood adversities and increasing protective relationships
through support and education of parents starting even before the birth of
the child. Later social interventions can also “reprogram” the brain in ways
that help to overcome the effects of early adversities. Longitudinal studies of
high-quality preschool programs in Michigan, North Carolina, and Illinois
provide evidence that early interventions with at-risk children can have
powerful long-lasting effects. For example, long-term follow-up of the
Highscope Perry School’s two-year preschool program for an experimental
group of 3- to 4-year-olds project has shown multiple benefits, including
higher rates of school completion, higher income for adults, and reduced
arrests (http://www.highscope.org/Content.asp?ContentId=219). Moreover, such high-quality early childhood programs as the Abecedarian Project
in North Carolina have been shown not only to have substantial benefits in
reducing crime, raising earnings, and promoting education but also significantly lower prevalence of risk factors for cardiovascular and metabolic diseases in the mid-30s, especially among males. The website of the National Scientific Council on the Developing Child is a rich source of information on this
topic (http://developingchild.harvard.edu/index.php/activities/council/)
(E).
GENETIC VARIANTS MATTER—ORCHID AND DANDELION CHILDREN
Recent research on children as well as studies using animal models also
makes us increasingly aware that commonly occurring genetic variants (alleles) make individuals differentially responsive to their environments. The
so-called “context-sensitive alleles” increase sensitivity to both positive and
negative experiences. As a result, children with such alleles do better than
average in functioning in positive school environments, while, in chaotic,
more stressful and less nurturing environments, such context-sensitive
children (“orchid children”) will do worse than the so-called “dandelion
children” who are far less responsive to context. It is not clear yet whether
“orchid” individuals might actually do better later in life in responding to
therapeutic interventions because of their context sensitivity and, possibly,
their greater capacity for plasticity via epigenetic mechanisms, compared to
“dandelion” individuals (B).

Social, Psychological, and Physiological Reactions to Stress

7

EPIGENETICS
Emerging knowledge of epigenetics further reveals the power of social
environments, experiences, and behavior to shape and reshape biology. “Epigenetics” refers to the seamless and continuous interaction between environmental and experiential factors and the genetic constitution of an individual.
Epigenetic mechanisms operate via folding and unfolding of the DNA double helix to repress or expose genes and involving modifications of DNA by
methylation of the cytosine base as well as through the operation of so-called
“non-coding” RNAs that modify how the primary RNA messages are processed and encoded into proteins. These mechanisms operate throughout the
life course and offer opportunities to change brain and body function at any
age, although making such changes becomes harder after the critical or sensitive developmental periods have past. Epigenetics emphasizes plasticity and
malleability, which can be observed at many different levels and not only at
the level of gene regulation. For example, environmentally regulated changes
can occur in neural architecture, involving limited neurogenesis and also the
turnover of synaptic connections and shrinkage and expansion of neuronal
dendritic trees. Yet, ultimately everything that happens to the cells of our
body influences the expression of our genetic code, and the modern science
of “epigenetics” has started to uncover multiple mechanisms that provide
many permutations and combinations with many possible outcomes.
Particularly noteworthy is the fact that genetically identical individuals can
become different owing to epigenetic effects of nonshared experiences (B).
Recent research by Meaney demonstrates the powerful effects that social
relationships can have on gene expression related to the experience of stress.
This research shows that the extent to which rat mothers lick and groom
their nursing pups affects whether or not at least the expression of one of
the pup’s genes is modified. When this epigenetic change takes place as a
result of intense licking and grooming, the pups will be better able to limit
their reactions to high-stress situations. This epigenetic change (with no
alteration in the DNA) then is later passed on by the pup to its offspring.
Emerging evidence from Chen, Miller, and colleagues about parallel epigenetic changes in human infants resulting from adversities suggests that
they affect genes that react to stress in ways affecting blood pressure and
heart rate. Over the life course, the result is a body with greater sensitivity
to stress and inflammation (B).
SUMMARY
Recent research and theorizing focus on biological stress processes in the
brain and body, in continuous interaction with social as well as physical environments and their effects on the health and life chances of individuals and

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

throughout the life course. As a result, biological stress mechanisms can reinforce broad social patterns of inequality—for example, increasing the chances
that poor children will be poor as adults and the likelihood that illnesses such
as depression, obesity, diabetes, and cardiovascular disease will occur more
frequently among the poor and working class. On the other hand, the plasticity of the brain and responsiveness of the body to the environment open up
opportunities through evidence-based interventions such as home visiting,
high-quality preschool education, and changes in social supports for parents to prevent or overcome early disadvantages and build the foundations
for productive and satisfying lives. The research also implies that reducing
the sources of toxic stress by interventions such as lowering poverty, supporting neighborhood development, and providing affordable, high-quality
child care can affect developing brains and provide long-term dividends in
health and well-being.
KEY ISSUES FOR FUTURE RESEARCH
This emerging view of closely interlinked biology, behavior, and social structures and relationships has many implications for both research and interventions. As a result, it is vital that there be both research collaborations across
disciplines and organized attention to communicating research results to policy makers. The research issues include the following:

•

•

•

Research to find ways to open “windows of plasticity” so that behavioral and social interventions can promote beneficial change even after
early adversity has occurred. We know that regular physical activity is
one way to do this, but research could open other ways to open those
windows (F).
Research to refine our understanding of which social and environmental conditions produce toxic stress and under what conditions. Current
research examines a wide array of adversities—environmental, interpersonal, social structural—but without either an organizing theory or
systematic evidence using consistent variables to indicate which adversities created by poverty matter most for toxic stress.
Enhance understanding of protective factors and the social structures
and resources that support them. We know that warm, supportive relationships and strong parent–child bonding protect against toxic stressors. But we know far less well how and why the availability of such
relationships varies across families and groups and what social interventions might be most effective in building those relationships and at
what ages they can be effective.

Social, Psychological, and Physiological Reactions to Stress

•

•

•

•

9

Research to elaborate our understanding of the epigenetic basis of context sensitivity and the ways that they influence the responses of infants
and children to their social environments. This research is in its early
stages. We need to know not only the early developmental implications
of context sensitivity and insensitivity but also their potential contributions to efforts to “reprogram” the plastic brain through later school
programs or therapeutic interventions.
Reorienting research on health, social and cognitive ability, social
mobility, and schooling to recognize the entire life course—especially
including early childhood. We are beginning to recognize the importance of experiences over the entire life course (the “life course
development model” by Halfon and colleagues) in the emerging
era of “epigenetics” and brain plasticity and brain–body reciprocal
interactions. In the domain of health, this has led to what is now called
“integrative medicine” to prevent as well as treat disorders in an era
when health care costs are increasing and people are living longer (B).
Systematic evaluation research on interventions to reduce toxic stress or
to overcome its effects on brain and body. In order to arrange our society
in order to realize human potential, research is needed to assess interventions such as high quality child care, parent education, income supports on children’s development, and their subsequent trajectories. This
research ideally should involve scholars of many disciplines in order to
gauge the nature and implementation of the interventions, their impact
on brain and body development, and school behavior and performance,
among other variables.
Research to assess macro-level social interventions. Which macrolevel
interventions, if any (such as widely available publicly supported child
care, universal family leave, income supports) reduce childhood adversity and toxic stress and improve developmental outcomes? Comparative international research or studies comparing localities or states with
differing social policies can help answer these questions. At the societal
level, the most important top-down interventions are the policies of government and the private sector that not only improve education but also
allow people to make choices that improve their chances for a healthy
life. For example, the Acheson report of the British Government in 1998
recognized that no public policy of virtually any kind should be enacted
without considering the implications for the health of all citizens. In
addition, private sectors policies that encourage healthy lifestyle practices among their employees are likely to gain reduced health insurance
costs and possibly a more loyal workforce (E).

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

FURTHER READING
A. Brain plasticity and role in memory, self regulation and mood
Bennett, E., Diamond, M., Krech, D., & Rosenzweig, M. (1964). Chemical and anatomical plasticity of brain. Science, 146, 610–619.
Gould, E. (2007). How widespread is adult neurogenesis in mammals? Nature
Reviews Neuroscience, 8, 481–488.
Gray, J. D., Rubin, T. G., Hunter, R. G., & McEwen, B. S. (2013). Hippocampal gene
expression changes underlying stress sensitization and recovery. Molecular Psychiatry, 19, 1171–1178.
Hebb, D. O. (1949). The organization of behavior; a neuropsychological theory. New York,
NY: Wiley.
Liston, C., Cichon, J. M., Jeanneteau, F., Jia, Z., Chao, M. V., & Gan, W. B. (2013). Circadian glucocorticoid oscillations promote learning-dependent synapse formation
and maintenance. Nature Neurosci, 16, 698–705.
McEwen, B. S. (1999). Stress and hippocampal plasticity. Annual Review of Neuroscience, 22, 105–122.
McEwen, B. S., & Morrison, J. H. (2013). The brain on stress: Vulnerability and plasticity of the prefrontal cortex over the life course. Neuron, 79, 16–29.
Roozendaal, B., McEwen, B. S., & Chattarji, S. (2009). Stress, memory and the amygdala. Nature Review of Neuroscience, 10, 423–433.
B. Epigenetics and individual differences
Boyce, W. T., & Ellis, B. J. (2005). Biological sensitivity to context: I. An evolutionarydevelopmental theory of the origins and functions of stress reactivity. Development
and Psychopathology, 17, 271–301.
Chen, E., Miller, G. E., Kobor, M. S., & Cole, S. W. (2011). Maternal warmth buffers
the effects of low early-life socioeconomic status on pro-inflammatory signaling
in adulthood. Molecular Psychiatry, 16, 729–737.
Fraga, M.F., E. Ballestar, M.F. Paz, S. Ropero, F. Setien, M.L. Ballestar … , M. Esteller.
2005. Epigenetic differences arise during the lifetime of monozygotic twins.
Proceedings of the National Academy of Sciences of the United States of America
102:10604–10609.
Halfon, N., Larson, K., Lu, M., Tullis, E., & Russ, S. (2014). Lifecourse health development: Past, present and future. Maternal and Child Health Journal, 18, 344–365.
Meaney, M. J. (2010). Epigenetics and the biological definition of gene × environment
interactions. Child Development, 81(1), 41–79.
Miller, G. E., & Chen, E. (2010). Harsh family climate in early life presages the emergence of a proinflammatory phenotype in adolescence. Psychological Science, 21,
848–856.
Obradovic, J., Bush, N. R., Stamperdahl, J., Adler, N. E., & Boyce, W. T. (2010). Biological sensitivity to context: The interactive effects of stress reactivity and family
adversity on socioemotional behavior and school readiness. Child Development, 81,
270–289.

Social, Psychological, and Physiological Reactions to Stress

11

Szyf, M., McGowan, P., & Meaney, M. J. (2008). The social environment and the
epigenome. Environmental and Molecular Mutagenesis, 49, 46–60.
C. Inequality in health, the brain and cognitive function
Acheson, S. D. (1998). Independent inquiry into inequalities in health report. London,
England: The Stationary Office.
Drewnowski, A., & Specter, S. E. (2004). Poverty and obesity: The role of energy density and energy costs. Am. J. Clin. Nutr., 79, 6–16.
Duncan, G. J., Magnuson, K., Kalil, A., & Ziol-Guest, K. (2012). The importance of
early childhood poverty. Social Indicators Research, 108(1), 87–98.
Duncan, G. J., Ziol-Guest, K. M., & Kalil, A. (2010). Early-childhood poverty and
adult attainment, behavior, and health. Child Development, 81(1), 306–325.
Evans, G. W., & Rosenbaum, J. (2008). Self-regulation and the income-achievement
gap. Early Childhood Research Quarterly, 23(4), 504–514. doi:10.1016/j.ecresq.2008.
07.002
Evans, G. W., & Schamberg, M. A. (2009). Childhood poverty, chronic stress, and
adult working memory. Proceedings of the National Academy of Sciences of the United
States of America, 106(16), 6545–6549.
Evans, G. W., & Wachs, T. D. (Eds.) (2010). Chaos and its influence on children’s development: An ecological perspective. Washington, DC: American Psychological Association.
Fernald, A., Marchman, V. A., & Weisleder, A. (2013). SES differences in language
processing skill and vocabulary are evident at 18 months. Developmental Science,
16(2), 234–248. doi:10.1111/desc.12019
Hart, B., & Risley, T. R. (1995). Meaningful differences in the everyday experience of young
American children. Baltimore, MD: Brookes Publishing Company.
Hackman, D. A., Farah, M. J., & Meaney, M. J. (2010). Socioeconomic status and the
brain: Mechanistic insights from human and animal research. Nature Reviews Neuroscience, 11, 651–659.
Kawachi, I., Kennedy, B. P., Lochner, K., & Prothrow-Stith, D. (1997). Social capital,
income inequality, and mortality. American Journal of Public Health, 87, 1491–1498.
Kim, P., Evans, G. W., Angstadt, M., Ho, S. S., Sripada, C. S., Swain, J. E., … , Phan, K.
L. (2013). Effects of childhood poverty and chronic stress on emotion regulatory
brain function in adulthood. Proceedings of the National Academy of Sciences of the
United States of America 110:18442–18447.
Sampson, R. J., Raudenbush, S. W., & Earls, F. (1997). Neighborhoods and violent
crime: A multilevel study of collective effects. Science, 277, 918–924.
D. Toxic Stress, Allostatic load and overload—impact on brain and body
Hawkley, L. C., & Cacioppo, J. T. (2010). Loneliness matters: A theoretical and empirical review of consequences and mechanisms. Annals of Behavioral Medicine, 40,
218–227.

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

Juster, R. P., McEwen, B. S., & Lupien, S. J. (2010). Allostatic load biomarkers
of chronic stress and impact on health and cognition. Neurosci & Biobehavioral
Reviews, 35, 2–16.
McEwen, B. S. (1998). Protective and damaging effects of stress mediators. The New
England Journal of Medicine, 338, 171–179.
McEwen, B. S. (2006). Protective and damaging effects of stress mediators: Central
role of the brain. Dialogues in Clinical Neuroscience: Stress, 8, 367–381.
McEwen, B. S., & Wingfield, J. C. (2003). The concept of allostasis in biology and
biomedicine. Hormones & Behavior, 43, 2–15.
Verstynen, T. D., Weinstein, A., Erickson, K. I., Sheu, L. K., Marsland, A. L., & Gianaros, P. J. (2013). Competing physiological pathways link individual differences
in weight and abdominal adiposity to white matter microstructure. Neuroimage,
79, 129–137.
Yau, P. L., Castro, M. G., Tagani, A., Tsui, W. H., & Convit, A. (2012). Obesity and
metabolic syndrome and functional and structural brain impairments in adolescence. Pediatrics, 130, e856–e864.
E. Social interventions
Aldana, S. G. (2001). Financial impact of health promotion programs: A comprehensive review of the literature. American Journal of Health Promotion, 15, 296–320.
Boyle, P. A., Buchman, A. S., Barnes, L. L., & Bennett, D. A. (2010). Effect of a purpose
in life on risk of incident Alzheimer disease and mild cognitive impairment in
community-dwelling older persons. Archives of General Psychiatry, 67, 304–310.
Campbell, F., Conti, G., Heckman, J. J., Moon, S. H., Pinto, R., Pungello, E., & Pan, Y.
(2014). Early childhood investments substantially boost adult health. Science, 343,
1478–1485.
Carlson, M. C., Erickson, K. I., Kramer, A. F., Voss, M. W., Bolea, N., … , Fried, L.
P. (2009). Evidence for neurocognitive plasticity in at-risk older adults: The experience corps program. The Journals of Gerontology Series A: Biological Sciences and
Medical Sciences 64: 1275–1282.
Duncan, G. J., & Sojourner, A. J. (2013). Can intensive early childhood intervention programs eliminate income-based cognitive and achievement gaps? Journal
of Human Resources, 48(4), 945–968.
Suskind, D., Leffel, K. R., Hernandez, M. W., Sapolich, S. G., Suskind, E., Kirkham,
E., & Meehan, P. (2013). An exploratory study of ‘quantitative linguistic feedback’:
Effect of LENA feedback on adult language production. Communication Disorders
Quarterly, 34(4), 199–209.
F. Physical activity and learning effects on brain
Draganski, B., Gaser, C., Kempermann, G., Kuhn, H. G., Winkler, J., Buchel, C., &
May, A. (2006). Temporal and spatial dynamics of brain structure changes during
extensive learning. Journal of Neuroscience, 26, 6314–6317.

Social, Psychological, and Physiological Reactions to Stress

13

Erickson, K. I., Voss, M. W., Prakash, R. S., Basak, C., Szabo, A., Chaddock,
L., … , Kramer, A. F.. (2011). Exercise training increases size of hippocampus and
improves memory. Proceedings of the National Academy of Sciences of the United States
of America 108: 3017–3022.
G. Effects of early life adversity and lifecourse developmental perspective
Anda, R. F., Butchart, A., Felitti, V. J., & Brown, D. W. (2010). Building a framework for
global surveillance of the public health implications of adverse childhood experiences. American Journal of Preventive Medicine, 39, 93–98.
Evans, G. W., Li, D., & Whipple, S. S. (2013). Cumulative risk and child development.
Psychological Bulletin, 139(6), 1342–1396.
Felitti, V. J., Anda, R. F., Nordenberg, D., Williamson, D. F., Spitz, A. M., Edwards,
V., … , Marks, J. S. (1998). Relationship of childhood abuse and household dysfunction to many of the leading causes of death in adults. The adverse childhood
experiences (ACE) study. American Journal of Preventive Medicine. 14: 245–258.
Lupien, S. J., Parent, S., Evans, A. C., Tremblay, R. E., Zelazo, P. D., Corbo,
V., … , Seguin, J. R. (2011). Larger amygdala but no change in hippocampal volume
in 10-year-old children exposed to maternal depressive symptomatology since
birth. Proceedings of the National Academy of Sciences of the United States of America
108: 14324–14329.

BRUCE S. McEWEN SHORT BIOGRAPHY
Bruce S. McEwen obtained his PhD in Cell Biology in 1964 from the Rockefeller University. He is a member of the US National Academy of Sciences,
the Institute of Medicine, and the American Academy of Arts and Sciences.
He served as President of the Society for Neuroscience in 1997–1998. As a
neuroscientist and neuroendocrinologist, McEwen studies environmentally
regulated, variable gene expression in the brain, mediated by circulating
steroid hormones and endogenous neurotransmitters in relation to brain
sexual differentiation and the actions of sex and stress hormones on the
adult brain, in particular related to structural and functional plasticity via
epigenetic mechanisms. His laboratory discovered adrenal steroid receptors
in the hippocampus in 1968. His laboratory combines molecular, anatomical,
pharmacological, physiological, and behavioral methodologies and relates
their findings to human clinical information. His current research focuses on
stress effects on amygdala and prefrontal cortex, as well as the hippocampus,
and his laboratory also investigates sex hormone effects and sex differences
in these brain regions involved in cognitive function and mood regulation.
He served on the MacArthur Foundation Research Network on Socioeconomic Status and Health, in which he has helped to reformulate concepts
and measurements related to stress and stress hormones in the context of

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human societies, which led to the concept of “allostatic load and overload”
that describes the wear and tear on the body and brain from chronic stress
and related life style behaviors that lead to dysregulation of physiological
stress pathways that are normally protective. He is also a member of the
National Council on the Developing Child, which focuses on biological
embedding of early life experiences and promoting healthy brain development. He is the coauthor of a book with science writer, Elizabeth Lasley, for
a lay audience called “The End of Stress as We Know It,” published in 2002,
and “The Hostage Brain” with science writer, the late Harold M. Schmeck,
Jr., published in 1994, both of which are now available as eBooks.
Web: http://www.rockefeller.edu/labheads/mcewen/mcewen-lab.php
CRAIG A. McEWEN SHORT BIOGRAPHY
Craig A. McEwen is Daniel B. Fayerweather Professor of Political Economy and Sociology Emeritus at Bowdoin College where he taught from
1975 to 2012. A 1967 graduate of Oberlin College, he earned his PhD in
sociology at Harvard University in 1975 after teaching 4 years at Morgan
State College (now University). Over the past decade he has become deeply
involved in community initiatives addressing poverty and early childhood
development with the United Way of Mid Coast Maine particularly. For
example, he chairs the implementation committee for a home visiting
initiative that will expand those resources in the region. At Bowdoin he
helped to found the Center for the Common Good and then served as
Senior Faculty Fellow there for 5 years supporting student involvement
in community service and community-based courses. He developed and
taught a course that involved students in doing research with and for local
agencies providing services to low income clients. His scholarly interests
have followed this teaching and community engagement and now focus
particularly on the impact of poverty on child development. His early
research and writing examined community corrections in comparison in a
book, Designing Correctional Organizations for Youths. Over the next 30 years
his research and commentary focused largely on the legal profession, courts
and mediation programs—small claims, community, corporate, family and
general civil—and has been published widely in law reviews, social science
journals and professional magazines. He is coauthor of the treatise Mediation:
Law, Policy, Practice (with Sarah Cole, Nancy Rogers, James Coben, and Peter
N. Thompson). He also coauthored with Lynn Mather and Richard Maiman
an empirical study of Divorce Lawyers at Work: Varieties of Professionalism in
Practice, and with Nancy Rogers, Robert Bordone and Frank Sander wrote
Designing Systems and Processes for Managing Disputes. At Bowdoin he served
as Dean for Academic Affairs from 1999 to 2006.

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Social, Psychological, and
Physiological Reactions to Stress
BRUCE S. McEWEN and CRAIG A. McEWEN

Abstract
Emerging research examines biological processes not as primary causes of social outcomes but rather as mechanisms that themselves depend on social environments.
In particular, environments that produce toxic stress help shape brain development
and brain and body function throughout the lifespan. Early life stress, in particular, has serious consequences for life-long health and affects cognitive performance,
emotional intelligence, and self-regulation. Because the brain is plastic, social as well
as individual behavioral interventions can alter some of these developmental paths,
modifying brain function and individual life trajectories—but with increasing difficulty as children become adolescents and adults. Now reflecting the new era of “epigenetics” and a life course perspective, this new view of stress, the brain, and social
environments highlights the importance of the social, psychological, and biological sciences working together to elucidate underlying mechanisms both to expand
knowledge and help promote a better society.

INTRODUCTION
Emerging trends in our multidisciplinary understanding of the effects of
stress on health, behavior, and individual life trajectories have developed
in the context of long traditions of foundational research in sociology,
anthropology, and psychology and changing understandings of biology and
the brain. Biology has progressed through the DNA revolution, which early
on suggested to many in the social sciences and in the public that biologists
viewed genetic endowment as “destiny.” Moreover, the brain was long
regarded as separate from the rest of the body and stable in its architecture
laid down before birth. The connections between biology and the social
sciences were limited at best.
Yet the pioneering work of Hebb focused on the changing connections
among nerve cells in the brain in the formation of memories, and later
research by Bennett, Krech, Diamond, and Rosenzweig described the
Emerging Trends in the Social and Behavioral Sciences. Edited by Robert Scott and Stephen Kosslyn.
© 2015 John Wiley & Sons, Inc. ISBN 978-1-118-90077-2.

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growth of the cerebral cortex induced in animals by an enriched environment. Such research began to raise awareness of the dynamic nature
of the adult as well as the developing brain in response to experiences.
Now biology has entered the era of “epigenetics” (“above the genome,”
referring to the new science of the seamless interaction between genes
and the environment and the underlying mechanisms that link them),
which is unraveling the complexities of the regulation of genetic traits
by the environment and has pointed to the enormous range of possible
outcomes of environmental/experiential influences on the brain. This work
has opened new possibilities for understanding how stress-producing
social environments and behaviors and biological mechanisms responding
to those environments interact to shape brain and body function and life
trajectories. Now is the time when the social and biological sciences can
build on one another’s insights to deepen our understanding of patterned
human behavior as well as individual variations (A and B. After most
paragraphs, one or more letters will refer the reader to bibliographic sections
organized broadly by topic at the end of the article).
CUTTING-EDGE RESEARCH, CONCEPTS, AND THEORY
A central challenge at present is to connect social science research to emerging findings in biology and neuroscience in order to understand how socially
produced adversities get “under the skin” and what social factors buffer and
protect against adverse biological effects. Social structures and relationships
influence biology in at least four different ways, especially in the early
years of life. First, social environments can create adversities—extreme
poverty, physical abuse, and unsafe and chaotic neighborhoods—that
lead to toxic stress and allostatic overload (the negative physiological
cost to the body when the active adaptation to stressors—“allostasis”—is
overused or dysregulated). These in turn shape brain structure and
function and promote a variety of diseases (http://onlinelibrary.
wiley.com/doi/10.1111/nyas.2010.1186.issue-1/issuetoc). Second, secure
and warm relationships with caregivers can protect against some of the biological consequences of adversity. Third, social interventions—well-designed
preschooling, home visiting, and classroom programming—can take advantage of the brain’s plasticity either by preventing adverse changes or, when
such changes have taken place, can promote reprogramming of those parts
of the brain that have been disrupted by adversity and toxic stress. Fourth,
social relationships as well as social conditions have epigenetic effects
related to stress responsiveness that we are just coming to understand. A
new synthesis of biology, behavior, and the social environment is made
possible by emerging concepts of toxic stress, allostasis/allostatic overload,

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and plasticity of the brain as the central organ of stress and adaptation, all
in the context of epigenetics (C, D, E—see references, which are grouped by
topic).
TOXIC STRESS AND ALLOSTATIC LOAD/OVERLOAD
We now understand that the brain and body are connected in a network of
reciprocal interactions via the autonomic, neuroendocrine, metabolic, and
immune systems that regulate each other. What happens in the brain alters
the activity of these systems and affects multiple body systems concurrently.
These systems, in turn, send signals—both neural and biochemical—back
to the brain. Normal stress responses exemplify the operation of these
interacting systems and the allostatic responses that maintain balance
among them. Normally, response to an acute stressor involves a rapid
turning on of adrenalin secretion followed by cortisol secretion, leading to
altered immune response, improved memory, and energy replenishment as
well as more efficient cardiovascular function. When the stressor is over, the
adrenalin and cortisol responses are efficiently shut off. However, when the
stress–response system remains turned on in response to chronic stressors in
the environment, this network of body systems becomes dysregulated. Toxic
stress refers to this condition and the underlying biology can be understood
in terms of allostasis and allostatic load/overload (D).
Allostasis refers to the active process of responding to challenges by activating the autonomic, neuroendocrine, metabolic, and immune systems via the
brain, the organ that perceives and responds to potential threats. Normally,
allostatic responses lead to adaptation when they are turned on and off efficiently in response to stressful events and their conclusion. However, toxic
stress leads to “allostatic load and overload” when the hormonal mediators
of the stress response continue to act on the body in ways that create “wear
and tear” (D).
Allostatic overload leads to pathophysiology (physiological imbalance,
such as hyperglycemia or chronic inflammation leading to disease) and
accelerating progression of diseases such as cardiovascular disease, diabetes,
arthritis, and depression. It also affects cognitive function negatively, in part
through its compromising effect on self-regulation and executive function.
Self-regulation involves in part the capacity to restrain impulses, anger, and
inappropriate behavior. Executive function is an aspect of self-regulation
involving mobilization of short-term memory, capacity to sequence and shift
tasks, and focus attention—all important to planning, thinking and solving
problems. These compromised capacities in turn affect social behavior and
school as well as later occupational success. Thus, the toll taken by allostatic
overload is considerable (C, D).

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

Stressful life experiences produce toxic stress and allostatic load
(http://developingchild.harvard.edu/index.php/activities/council/).
Early life experiences are biologically embedded, in the sense that they can
have long-lasting effects on brain function and on brain–body interactions
that strongly influence life course trajectories. The Adverse Childhood
Experiences (ACE) study led by Drs Vincent Fellitti and Robert Anda
revealed the long-lasting consequences for physical and mental health of
events early in a child’s life. An ACE score derives from counts of adversities
in childhood—including parental divorce, family member incarcerated,
alcohol or drug abuse or depression in family, harsh language, and physical
or sexual abuse. It is important to note that both mental health problems
such as depression; substance abuse and antisocial behavior; and physical
health disorders such as cardiovascular disease, chronic obstructive pulmonary disorder (COPD), and diabetes show a dose-dependent effect of
the ACE score (G). For the brain, a child growing up over a 10-year period
with a depressed mother will have an enlarged amygdala, a brain region
that mediates anxiety and fear. And, in addition to ACE, which occur at all
socioeconomic levels, long-term poverty adds a powerful additional stamp,
impairing the development of the prefrontal cortex and of self-regulatory
behavior through toxic stress, produced in part by chaotic and crowded
homes and dangerous neighborhoods. Alienation and social isolation
can also have devastating effects upon well-being, and both hostility and
loneliness are themselves severe stressors and contribute to allostatic load
(C, D G).
Importantly, supportive social relationships—especially from caregivers
in early childhood—help protect against allostatic overload in the face of
sustained environmental stressors (http://developingchild.harvard.edu/
resources/reports_and_working_papers/foundations-of-lifelong-health/).
Throughout the lifespan and particularly later in life, eudaimonic well-being
(feeling connected to a deeper purpose) is associated with lower allostatic
load and higher cognitive and physical function, as well as lower incidence
of dementia in the elderly when compared with hedonic well-being, (feeling
gratification from immediately pleasurable experiences) (E).
THE BRAIN’S PLASTICITY
Over the past several decades, we have become increasingly aware that the
structure and function of the brain are malleable as a result of experiences
in the physical and social environment, including the nature of social interactions, during development and in adult life. Building upon the work of
Hebb and Bennett, Krech, Diamond, and Rosenzweig, we now understand
the continuous turnover of at least some of the synaptic connections in the

Social, Psychological, and Physiological Reactions to Stress

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brain modulated by experience and mediated, in part, by the daily fluctuations of cortisol, otherwise known as a “stress” hormone but having many
other important functions. Moreover, limited development of new neurons
takes place in several parts of the brain, continues throughout adult life, and
can be altered both by experiences and by hormones (A).
Stressful experiences impair this plasticity, however, and cause reversible
changes in the neural architecture of healthy brains that promote vigilance
in the face of danger along with changes in gene expression reflective of
cumulative experiences. When these changes persist after danger passes, the
altered brain architecture can lead to anxiety and other mood disorders. Yet,
regular physical activity enhances plasticity and stimulates neuron development in and increases in the volume of the hippocampus while improving
memory and executive function; intense learning also changes brain architecture. In contrast, diabetes, which has increased in incidence in part as a
result of poverty and early life adversity, leads to impaired brain architecture even in teenagers, along with impaired cognitive function and increased
risk for Alzheimer’s disease later in life. Furthermore, perceptions of inequality in adults as a result of socioeconomic differences predict health status and
have correlates in aspects of brain structure and function, including impaired
white matter (the “insulation” of the brain) (A, D).
As we have seen, plasticity means that early childhood experiences affect
brain development. For example, language processing capacity and ability as
well as emotional intelligence grow in early “serve and return” interactions
between infants and caregivers (http://developingchild.harvard.edu/index.
php/activities/council/). When parents coo or gesture in response to their
infants or talk with their children, they are engaging in serve and return
interactions that play a key role in building brain architecture. One
example of serve and return involves linguistic interactions between
parents and caregivers. The pioneering research of Hart and Risley
and subsequent studies have shown that children from poor families
are likely to hear far fewer words than their counterparts in professional families with consequences for both their vocabularies and the
linguistic capacities of their brains. Ongoing research with recorders
that gauge volume of linguistic interaction between parents and children suggests that helpful monitoring and feedback increases verbal
interaction significantly. Serve and return interactions not only promote
language and cognitive development but are a key to strong attachments
with caregivers and increased capacity for self-regulation and empathy
(http://developingchild.harvard.edu/index.php/activities/council/) (C).
The implications of plasticity are two-sided. On the one hand, as we have
seen, adversities and toxic stress can impair brain architecture, especially

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

early in life. On the other hand, brain growth in response to positive interactions with caregivers builds strong brain architecture. Programs such as
the Nurse Family Partnership (http://www.nursefamilypartnership.org/)
intervene early on to build the positive and reduce the negative experiences
of early childhood. Evidence indicates home visiting has beneficial effects
by reducing childhood adversities and increasing protective relationships
through support and education of parents starting even before the birth of
the child. Later social interventions can also “reprogram” the brain in ways
that help to overcome the effects of early adversities. Longitudinal studies of
high-quality preschool programs in Michigan, North Carolina, and Illinois
provide evidence that early interventions with at-risk children can have
powerful long-lasting effects. For example, long-term follow-up of the
Highscope Perry School’s two-year preschool program for an experimental
group of 3- to 4-year-olds project has shown multiple benefits, including
higher rates of school completion, higher income for adults, and reduced
arrests (http://www.highscope.org/Content.asp?ContentId=219). Moreover, such high-quality early childhood programs as the Abecedarian Project
in North Carolina have been shown not only to have substantial benefits in
reducing crime, raising earnings, and promoting education but also significantly lower prevalence of risk factors for cardiovascular and metabolic diseases in the mid-30s, especially among males. The website of the National Scientific Council on the Developing Child is a rich source of information on this
topic (http://developingchild.harvard.edu/index.php/activities/council/)
(E).
GENETIC VARIANTS MATTER—ORCHID AND DANDELION CHILDREN
Recent research on children as well as studies using animal models also
makes us increasingly aware that commonly occurring genetic variants (alleles) make individuals differentially responsive to their environments. The
so-called “context-sensitive alleles” increase sensitivity to both positive and
negative experiences. As a result, children with such alleles do better than
average in functioning in positive school environments, while, in chaotic,
more stressful and less nurturing environments, such context-sensitive
children (“orchid children”) will do worse than the so-called “dandelion
children” who are far less responsive to context. It is not clear yet whether
“orchid” individuals might actually do better later in life in responding to
therapeutic interventions because of their context sensitivity and, possibly,
their greater capacity for plasticity via epigenetic mechanisms, compared to
“dandelion” individuals (B).

Social, Psychological, and Physiological Reactions to Stress

7

EPIGENETICS
Emerging knowledge of epigenetics further reveals the power of social
environments, experiences, and behavior to shape and reshape biology. “Epigenetics” refers to the seamless and continuous interaction between environmental and experiential factors and the genetic constitution of an individual.
Epigenetic mechanisms operate via folding and unfolding of the DNA double helix to repress or expose genes and involving modifications of DNA by
methylation of the cytosine base as well as through the operation of so-called
“non-coding” RNAs that modify how the primary RNA messages are processed and encoded into proteins. These mechanisms operate throughout the
life course and offer opportunities to change brain and body function at any
age, although making such changes becomes harder after the critical or sensitive developmental periods have past. Epigenetics emphasizes plasticity and
malleability, which can be observed at many different levels and not only at
the level of gene regulation. For example, environmentally regulated changes
can occur in neural architecture, involving limited neurogenesis and also the
turnover of synaptic connections and shrinkage and expansion of neuronal
dendritic trees. Yet, ultimately everything that happens to the cells of our
body influences the expression of our genetic code, and the modern science
of “epigenetics” has started to uncover multiple mechanisms that provide
many permutations and combinations with many possible outcomes.
Particularly noteworthy is the fact that genetically identical individuals can
become different owing to epigenetic effects of nonshared experiences (B).
Recent research by Meaney demonstrates the powerful effects that social
relationships can have on gene expression related to the experience of stress.
This research shows that the extent to which rat mothers lick and groom
their nursing pups affects whether or not at least the expression of one of
the pup’s genes is modified. When this epigenetic change takes place as a
result of intense licking and grooming, the pups will be better able to limit
their reactions to high-stress situations. This epigenetic change (with no
alteration in the DNA) then is later passed on by the pup to its offspring.
Emerging evidence from Chen, Miller, and colleagues about parallel epigenetic changes in human infants resulting from adversities suggests that
they affect genes that react to stress in ways affecting blood pressure and
heart rate. Over the life course, the result is a body with greater sensitivity
to stress and inflammation (B).
SUMMARY
Recent research and theorizing focus on biological stress processes in the
brain and body, in continuous interaction with social as well as physical environments and their effects on the health and life chances of individuals and

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

throughout the life course. As a result, biological stress mechanisms can reinforce broad social patterns of inequality—for example, increasing the chances
that poor children will be poor as adults and the likelihood that illnesses such
as depression, obesity, diabetes, and cardiovascular disease will occur more
frequently among the poor and working class. On the other hand, the plasticity of the brain and responsiveness of the body to the environment open up
opportunities through evidence-based interventions such as home visiting,
high-quality preschool education, and changes in social supports for parents to prevent or overcome early disadvantages and build the foundations
for productive and satisfying lives. The research also implies that reducing
the sources of toxic stress by interventions such as lowering poverty, supporting neighborhood development, and providing affordable, high-quality
child care can affect developing brains and provide long-term dividends in
health and well-being.
KEY ISSUES FOR FUTURE RESEARCH
This emerging view of closely interlinked biology, behavior, and social structures and relationships has many implications for both research and interventions. As a result, it is vital that there be both research collaborations across
disciplines and organized attention to communicating research results to policy makers. The research issues include the following:

•

•

•

Research to find ways to open “windows of plasticity” so that behavioral and social interventions can promote beneficial change even after
early adversity has occurred. We know that regular physical activity is
one way to do this, but research could open other ways to open those
windows (F).
Research to refine our understanding of which social and environmental conditions produce toxic stress and under what conditions. Current
research examines a wide array of adversities—environmental, interpersonal, social structural—but without either an organizing theory or
systematic evidence using consistent variables to indicate which adversities created by poverty matter most for toxic stress.
Enhance understanding of protective factors and the social structures
and resources that support them. We know that warm, supportive relationships and strong parent–child bonding protect against toxic stressors. But we know far less well how and why the availability of such
relationships varies across families and groups and what social interventions might be most effective in building those relationships and at
what ages they can be effective.

Social, Psychological, and Physiological Reactions to Stress

•

•

•

•

9

Research to elaborate our understanding of the epigenetic basis of context sensitivity and the ways that they influence the responses of infants
and children to their social environments. This research is in its early
stages. We need to know not only the early developmental implications
of context sensitivity and insensitivity but also their potential contributions to efforts to “reprogram” the plastic brain through later school
programs or therapeutic interventions.
Reorienting research on health, social and cognitive ability, social
mobility, and schooling to recognize the entire life course—especially
including early childhood. We are beginning to recognize the importance of experiences over the entire life course (the “life course
development model” by Halfon and colleagues) in the emerging
era of “epigenetics” and brain plasticity and brain–body reciprocal
interactions. In the domain of health, this has led to what is now called
“integrative medicine” to prevent as well as treat disorders in an era
when health care costs are increasing and people are living longer (B).
Systematic evaluation research on interventions to reduce toxic stress or
to overcome its effects on brain and body. In order to arrange our society
in order to realize human potential, research is needed to assess interventions such as high quality child care, parent education, income supports on children’s development, and their subsequent trajectories. This
research ideally should involve scholars of many disciplines in order to
gauge the nature and implementation of the interventions, their impact
on brain and body development, and school behavior and performance,
among other variables.
Research to assess macro-level social interventions. Which macrolevel
interventions, if any (such as widely available publicly supported child
care, universal family leave, income supports) reduce childhood adversity and toxic stress and improve developmental outcomes? Comparative international research or studies comparing localities or states with
differing social policies can help answer these questions. At the societal
level, the most important top-down interventions are the policies of government and the private sector that not only improve education but also
allow people to make choices that improve their chances for a healthy
life. For example, the Acheson report of the British Government in 1998
recognized that no public policy of virtually any kind should be enacted
without considering the implications for the health of all citizens. In
addition, private sectors policies that encourage healthy lifestyle practices among their employees are likely to gain reduced health insurance
costs and possibly a more loyal workforce (E).

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

FURTHER READING
A. Brain plasticity and role in memory, self regulation and mood
Bennett, E., Diamond, M., Krech, D., & Rosenzweig, M. (1964). Chemical and anatomical plasticity of brain. Science, 146, 610–619.
Gould, E. (2007). How widespread is adult neurogenesis in mammals? Nature
Reviews Neuroscience, 8, 481–488.
Gray, J. D., Rubin, T. G., Hunter, R. G., & McEwen, B. S. (2013). Hippocampal gene
expression changes underlying stress sensitization and recovery. Molecular Psychiatry, 19, 1171–1178.
Hebb, D. O. (1949). The organization of behavior; a neuropsychological theory. New York,
NY: Wiley.
Liston, C., Cichon, J. M., Jeanneteau, F., Jia, Z., Chao, M. V., & Gan, W. B. (2013). Circadian glucocorticoid oscillations promote learning-dependent synapse formation
and maintenance. Nature Neurosci, 16, 698–705.
McEwen, B. S. (1999). Stress and hippocampal plasticity. Annual Review of Neuroscience, 22, 105–122.
McEwen, B. S., & Morrison, J. H. (2013). The brain on stress: Vulnerability and plasticity of the prefrontal cortex over the life course. Neuron, 79, 16–29.
Roozendaal, B., McEwen, B. S., & Chattarji, S. (2009). Stress, memory and the amygdala. Nature Review of Neuroscience, 10, 423–433.
B. Epigenetics and individual differences
Boyce, W. T., & Ellis, B. J. (2005). Biological sensitivity to context: I. An evolutionarydevelopmental theory of the origins and functions of stress reactivity. Development
and Psychopathology, 17, 271–301.
Chen, E., Miller, G. E., Kobor, M. S., & Cole, S. W. (2011). Maternal warmth buffers
the effects of low early-life socioeconomic status on pro-inflammatory signaling
in adulthood. Molecular Psychiatry, 16, 729–737.
Fraga, M.F., E. Ballestar, M.F. Paz, S. Ropero, F. Setien, M.L. Ballestar … , M. Esteller.
2005. Epigenetic differences arise during the lifetime of monozygotic twins.
Proceedings of the National Academy of Sciences of the United States of America
102:10604–10609.
Halfon, N., Larson, K., Lu, M., Tullis, E., & Russ, S. (2014). Lifecourse health development: Past, present and future. Maternal and Child Health Journal, 18, 344–365.
Meaney, M. J. (2010). Epigenetics and the biological definition of gene × environment
interactions. Child Development, 81(1), 41–79.
Miller, G. E., & Chen, E. (2010). Harsh family climate in early life presages the emergence of a proinflammatory phenotype in adolescence. Psychological Science, 21,
848–856.
Obradovic, J., Bush, N. R., Stamperdahl, J., Adler, N. E., & Boyce, W. T. (2010). Biological sensitivity to context: The interactive effects of stress reactivity and family
adversity on socioemotional behavior and school readiness. Child Development, 81,
270–289.

Social, Psychological, and Physiological Reactions to Stress

11

Szyf, M., McGowan, P., & Meaney, M. J. (2008). The social environment and the
epigenome. Environmental and Molecular Mutagenesis, 49, 46–60.
C. Inequality in health, the brain and cognitive function
Acheson, S. D. (1998). Independent inquiry into inequalities in health report. London,
England: The Stationary Office.
Drewnowski, A., & Specter, S. E. (2004). Poverty and obesity: The role of energy density and energy costs. Am. J. Clin. Nutr., 79, 6–16.
Duncan, G. J., Magnuson, K., Kalil, A., & Ziol-Guest, K. (2012). The importance of
early childhood poverty. Social Indicators Research, 108(1), 87–98.
Duncan, G. J., Ziol-Guest, K. M., & Kalil, A. (2010). Early-childhood poverty and
adult attainment, behavior, and health. Child Development, 81(1), 306–325.
Evans, G. W., & Rosenbaum, J. (2008). Self-regulation and the income-achievement
gap. Early Childhood Research Quarterly, 23(4), 504–514. doi:10.1016/j.ecresq.2008.
07.002
Evans, G. W., & Schamberg, M. A. (2009). Childhood poverty, chronic stress, and
adult working memory. Proceedings of the National Academy of Sciences of the United
States of America, 106(16), 6545–6549.
Evans, G. W., & Wachs, T. D. (Eds.) (2010). Chaos and its influence on children’s development: An ecological perspective. Washington, DC: American Psychological Association.
Fernald, A., Marchman, V. A., & Weisleder, A. (2013). SES differences in language
processing skill and vocabulary are evident at 18 months. Developmental Science,
16(2), 234–248. doi:10.1111/desc.12019
Hart, B., & Risley, T. R. (1995). Meaningful differences in the everyday experience of young
American children. Baltimore, MD: Brookes Publishing Company.
Hackman, D. A., Farah, M. J., & Meaney, M. J. (2010). Socioeconomic status and the
brain: Mechanistic insights from human and animal research. Nature Reviews Neuroscience, 11, 651–659.
Kawachi, I., Kennedy, B. P., Lochner, K., & Prothrow-Stith, D. (1997). Social capital,
income inequality, and mortality. American Journal of Public Health, 87, 1491–1498.
Kim, P., Evans, G. W., Angstadt, M., Ho, S. S., Sripada, C. S., Swain, J. E., … , Phan, K.
L. (2013). Effects of childhood poverty and chronic stress on emotion regulatory
brain function in adulthood. Proceedings of the National Academy of Sciences of the
United States of America 110:18442–18447.
Sampson, R. J., Raudenbush, S. W., & Earls, F. (1997). Neighborhoods and violent
crime: A multilevel study of collective effects. Science, 277, 918–924.
D. Toxic Stress, Allostatic load and overload—impact on brain and body
Hawkley, L. C., & Cacioppo, J. T. (2010). Loneliness matters: A theoretical and empirical review of consequences and mechanisms. Annals of Behavioral Medicine, 40,
218–227.

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

Juster, R. P., McEwen, B. S., & Lupien, S. J. (2010). Allostatic load biomarkers
of chronic stress and impact on health and cognition. Neurosci & Biobehavioral
Reviews, 35, 2–16.
McEwen, B. S. (1998). Protective and damaging effects of stress mediators. The New
England Journal of Medicine, 338, 171–179.
McEwen, B. S. (2006). Protective and damaging effects of stress mediators: Central
role of the brain. Dialogues in Clinical Neuroscience: Stress, 8, 367–381.
McEwen, B. S., & Wingfield, J. C. (2003). The concept of allostasis in biology and
biomedicine. Hormones & Behavior, 43, 2–15.
Verstynen, T. D., Weinstein, A., Erickson, K. I., Sheu, L. K., Marsland, A. L., & Gianaros, P. J. (2013). Competing physiological pathways link individual differences
in weight and abdominal adiposity to white matter microstructure. Neuroimage,
79, 129–137.
Yau, P. L., Castro, M. G., Tagani, A., Tsui, W. H., & Convit, A. (2012). Obesity and
metabolic syndrome and functional and structural brain impairments in adolescence. Pediatrics, 130, e856–e864.
E. Social interventions
Aldana, S. G. (2001). Financial impact of health promotion programs: A comprehensive review of the literature. American Journal of Health Promotion, 15, 296–320.
Boyle, P. A., Buchman, A. S., Barnes, L. L., & Bennett, D. A. (2010). Effect of a purpose
in life on risk of incident Alzheimer disease and mild cognitive impairment in
community-dwelling older persons. Archives of General Psychiatry, 67, 304–310.
Campbell, F., Conti, G., Heckman, J. J., Moon, S. H., Pinto, R., Pungello, E., & Pan, Y.
(2014). Early childhood investments substantially boost adult health. Science, 343,
1478–1485.
Carlson, M. C., Erickson, K. I., Kramer, A. F., Voss, M. W., Bolea, N., … , Fried, L.
P. (2009). Evidence for neurocognitive plasticity in at-risk older adults: The experience corps program. The Journals of Gerontology Series A: Biological Sciences and
Medical Sciences 64: 1275–1282.
Duncan, G. J., & Sojourner, A. J. (2013). Can intensive early childhood intervention programs eliminate income-based cognitive and achievement gaps? Journal
of Human Resources, 48(4), 945–968.
Suskind, D., Leffel, K. R., Hernandez, M. W., Sapolich, S. G., Suskind, E., Kirkham,
E., & Meehan, P. (2013). An exploratory study of ‘quantitative linguistic feedback’:
Effect of LENA feedback on adult language production. Communication Disorders
Quarterly, 34(4), 199–209.
F. Physical activity and learning effects on brain
Draganski, B., Gaser, C., Kempermann, G., Kuhn, H. G., Winkler, J., Buchel, C., &
May, A. (2006). Temporal and spatial dynamics of brain structure changes during
extensive learning. Journal of Neuroscience, 26, 6314–6317.

Social, Psychological, and Physiological Reactions to Stress

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Erickson, K. I., Voss, M. W., Prakash, R. S., Basak, C., Szabo, A., Chaddock,
L., … , Kramer, A. F.. (2011). Exercise training increases size of hippocampus and
improves memory. Proceedings of the National Academy of Sciences of the United States
of America 108: 3017–3022.
G. Effects of early life adversity and lifecourse developmental perspective
Anda, R. F., Butchart, A., Felitti, V. J., & Brown, D. W. (2010). Building a framework for
global surveillance of the public health implications of adverse childhood experiences. American Journal of Preventive Medicine, 39, 93–98.
Evans, G. W., Li, D., & Whipple, S. S. (2013). Cumulative risk and child development.
Psychological Bulletin, 139(6), 1342–1396.
Felitti, V. J., Anda, R. F., Nordenberg, D., Williamson, D. F., Spitz, A. M., Edwards,
V., … , Marks, J. S. (1998). Relationship of childhood abuse and household dysfunction to many of the leading causes of death in adults. The adverse childhood
experiences (ACE) study. American Journal of Preventive Medicine. 14: 245–258.
Lupien, S. J., Parent, S., Evans, A. C., Tremblay, R. E., Zelazo, P. D., Corbo,
V., … , Seguin, J. R. (2011). Larger amygdala but no change in hippocampal volume
in 10-year-old children exposed to maternal depressive symptomatology since
birth. Proceedings of the National Academy of Sciences of the United States of America
108: 14324–14329.

BRUCE S. McEWEN SHORT BIOGRAPHY
Bruce S. McEwen obtained his PhD in Cell Biology in 1964 from the Rockefeller University. He is a member of the US National Academy of Sciences,
the Institute of Medicine, and the American Academy of Arts and Sciences.
He served as President of the Society for Neuroscience in 1997–1998. As a
neuroscientist and neuroendocrinologist, McEwen studies environmentally
regulated, variable gene expression in the brain, mediated by circulating
steroid hormones and endogenous neurotransmitters in relation to brain
sexual differentiation and the actions of sex and stress hormones on the
adult brain, in particular related to structural and functional plasticity via
epigenetic mechanisms. His laboratory discovered adrenal steroid receptors
in the hippocampus in 1968. His laboratory combines molecular, anatomical,
pharmacological, physiological, and behavioral methodologies and relates
their findings to human clinical information. His current research focuses on
stress effects on amygdala and prefrontal cortex, as well as the hippocampus,
and his laboratory also investigates sex hormone effects and sex differences
in these brain regions involved in cognitive function and mood regulation.
He served on the MacArthur Foundation Research Network on Socioeconomic Status and Health, in which he has helped to reformulate concepts
and measurements related to stress and stress hormones in the context of

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human societies, which led to the concept of “allostatic load and overload”
that describes the wear and tear on the body and brain from chronic stress
and related life style behaviors that lead to dysregulation of physiological
stress pathways that are normally protective. He is also a member of the
National Council on the Developing Child, which focuses on biological
embedding of early life experiences and promoting healthy brain development. He is the coauthor of a book with science writer, Elizabeth Lasley, for
a lay audience called “The End of Stress as We Know It,” published in 2002,
and “The Hostage Brain” with science writer, the late Harold M. Schmeck,
Jr., published in 1994, both of which are now available as eBooks.
Web: http://www.rockefeller.edu/labheads/mcewen/mcewen-lab.php
CRAIG A. McEWEN SHORT BIOGRAPHY
Craig A. McEwen is Daniel B. Fayerweather Professor of Political Economy and Sociology Emeritus at Bowdoin College where he taught from
1975 to 2012. A 1967 graduate of Oberlin College, he earned his PhD in
sociology at Harvard University in 1975 after teaching 4 years at Morgan
State College (now University). Over the past decade he has become deeply
involved in community initiatives addressing poverty and early childhood
development with the United Way of Mid Coast Maine particularly. For
example, he chairs the implementation committee for a home visiting
initiative that will expand those resources in the region. At Bowdoin he
helped to found the Center for the Common Good and then served as
Senior Faculty Fellow there for 5 years supporting student involvement
in community service and community-based courses. He developed and
taught a course that involved students in doing research with and for local
agencies providing services to low income clients. His scholarly interests
have followed this teaching and community engagement and now focus
particularly on the impact of poverty on child development. His early
research and writing examined community corrections in comparison in a
book, Designing Correctional Organizations for Youths. Over the next 30 years
his research and commentary focused largely on the legal profession, courts
and mediation programs—small claims, community, corporate, family and
general civil—and has been published widely in law reviews, social science
journals and professional magazines. He is coauthor of the treatise Mediation:
Law, Policy, Practice (with Sarah Cole, Nancy Rogers, James Coben, and Peter
N. Thompson). He also coauthored with Lynn Mather and Richard Maiman
an empirical study of Divorce Lawyers at Work: Varieties of Professionalism in
Practice, and with Nancy Rogers, Robert Bordone and Frank Sander wrote
Designing Systems and Processes for Managing Disputes. At Bowdoin he served
as Dean for Academic Affairs from 1999 to 2006.

Social, Psychological, and Physiological Reactions to Stress

15

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