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Biology of Stress●Function of the limbic system and basal ganglia
●(SAM) – Sympathetic-adrenal-medullary– Epinephrine and norepinephrine
●(HPA) – Hypothalamus-pituitary-adrenal– Glucocorticoids
● Cortisol
Effects of Stress●Cortisol modulates
– Energy– Immune activity– Mental alertness– Learning– Memory encoding
● Why do we care about cortisol and family environment?– Psychosocial stress and uncertainty
Costs of Stress●Chronic stress can lead to:
– Immunity deficiencies– Stunted growth– Hippocampal damage– Cognitive impairment
● Permanent alteration of HPA functioning– Prenatal drug exposure– Abuse victims
Challenges●Factors influencing cortisol levels:
– Circadian rhythm
– Food consumption
– Physical activity
● Emotional distress?– Time course of endocrine functions
– Individual variation● Temperament
A Useful Approach●How do we account for all of these factors?
– Longitudinal Anthropological study
● Both behavior and cortisol assay– Short-term as well as long-term events
● Provides cultural context– Cultural significance of events– Individuation of subjects
● Personality● Past experiences
•247 Children 2 months-18 years from 82 homes-nearly complete sample•Bwa Mawego, rural village in Dominica
•+/- 780 residents•Divided into 5 neighborhoods, 4 of which were involved in this study
•Mixed African, Carib, and European descents
Population
About Bwa Mawego Small houses, most have kitchen and toilet as
outbuildings Children typically sleep together Wealthier houses have sitting rooms ~60% of homes and electricity
• Part time residence common
• Large farming and fishing community
• No running water-obtained from springs, catchments and run-off from roofs
Methods and Field Techniques• Interviews, behavioral scans, participant
observation, and questionnaire instruments Household environment, caretaking attention,
temperament, and health
• Radioimmunoassay of saliva samples Physiological stress response
Primary focus of this report in on relations between stress (dependent variable) and family environment (independent variable)
Saliva collectionRoutine 1:
Twice daily collection16,652 of 18,376 collections this way
Routine 2:“focal follow”Child/infant was observed from dawn until
early afternoon with hourly saliva samples
Data was NOT adjusted for…Eating and caffeine intake
Few samples were taken during mealtime Small effect
Intensive physical exertion Only small amount of samples taken during
physical exertion Difficult to determine degree of exertions
Circadian Rhythm24-hour cycle in biochemical, physiological,
or behavioral processesIncludes release of cortisol!
From these results, the conclusion is that childhood stress is associated with household compositionChildren in difficult caretaking environments
may experience… chronic stress more acute stressors More frequent stressful events May have inadequate coping abilities, perhaps
developed from difficult experiences in early childhood
Chronic StressChronic stress…
May deplete cellular energy and immune reserves that require subsequent conservation to rebuild normal cortisol
Along with high average cortisol levels are associated with frequency of illness
“Sensitive Periods”Longitudinal analysis of caretaking histories
suggest that children have “sensitive periods” for development of stress responseChildren with severe caretaking problems
during INFANCY frequently exhibit one of two cortisol profiles Unusually low with occasional high spikes Chronically high cortisol levels
Step children are more likely to have unusual cortisol profiles and inhibited temperaments
Low-basal-with-high spikes cortisol profile children all have low sociability and high aggressiveness.
All children with the chronically high cortisol profile have shyness and social anxiety.
High StressHigh stress does not mean the events that
triggered were traumatic or “negative” Eating meals Hard physical work Routine competitive play Return of a family member who was temporarily
absent
SummaryStress coping mechanisms
Beneficial in the short termConsume extensive resources
Leave the body vulnerable after prolonged use
Children are especially sensitive to stressMight be due to extreme exposure
Its hard to escape parentsChildren have sensitive periods, this allows
them to learn better during certain times.
DiscussionLimitations
Only used sample of people in a rural villageDid stress levels of parents interact with that
of children. If parents did not act stress did their cortisol levels
effect those of their childrenNot experimental or controlled
Future studiesTake place in the cityDoes children’s stress effect parentsExplicit effects on personalityDoes animal parental stress effect children or
is this uniquely humanMediation of effects?
Implications•Parents need to be extra attentive to stress levels.
•A bad start can lead to repeated stress
•Small amounts of stress may lead to development of coping mechanisms
•Engaging children in activities that activate stress could be beneficial. I.E. Sports.
•Children need strong support systems
Relationship to EPStress in the environment is relatively
short livedZebra gets attack, zebra runs, stress
is over.In modern times stressful situations
last much longer Imagine being attacked by a lion 8 hours
a day.Supported by finding that stress levels
in people decrease after short time.Could be adaptive to respond to
parents feelings quickly. E.X. Mom scared of lion, good to scare
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