Developmental Ecology and Human Biology Lab

Numerous biomarkers of immune or endocrine function are measurable in saliva or dried blood spots. Biomarkers allow us to examine proximal physiological processes that bridge the gap between daily experience and health. Representative assays currently in use in the lab include:

• Salivary cortisol. Cortisol is the major peripheral end product of the hypothalamic-pituitary-adrenal axis and has a long history of use in biocultural or biosocial research as a "stress hormone" given the robust cortisol response to psychological distress. Beyond stress, cortisol is involved in arousal regulation quite broadly, and has widespread peripheral and central regulatory functions.
• Salivary α-amylase. An enzyme found in human saliva, α-amylase has received recent attention as a marker of acute psychosocial stress. However, additional validation work is required before it can be fully accepted as a useful marker for field-based research. The lab has been investigating its utility in field settings of the type routinely encountered by anthropologists. 
• C-reactive protein. CRP, an acute phase protein that can be detected in dried blood spots, serves as a marker of inflammation and infectious disease load. Chronically high CRP levels may be associated with elevated cardiovascular risk.
• Antibodies against the Epstein-Barr Virus. EBV is a ubiquitous herpesvirus. Antibodies against the EBV viral capsid antigen can be detected in dried blood spots, and serve as a marker of chronic stress and allostatic load.

1. DeCaro JA, Worthman CM. 2011. Changing family routines at kindergarten entry predict biomarkers of parental stress. International Journal of Behavioral Development 35(5):441-448. View the abstract. Full text pdf available upon request.
2. DeCaro JA, DeCaro E, Worthman CM. 2010. Sex differences in child nutritional and immunological status 5-9 years post contact in fringe highland Papua New Guinea. American Journal of Human Biology 22(5):657-666. View the abstract. Full text pdf available upon request.
3. DeCaro JA. 2009. Novel non-invasive alternatives for the measurement of autonomic stress responses in children and adults [abstract]. American Journal of Physical Anthropology 138(S48):116-117.
4. DeCaro JA. 2008. Methodological considerations in the use of salivary α-amylase as a stress marker in field research. American Journal of Human Biology 20(5):617-619. View the abstract. Full text pdf available upon request.
5. DeCaro JA, Worthman CM. 2008. Return to school accompanied by changing associations between family ecology and cortisol. Developmental Psychobiology 50(2):183-195. View the abstract. Full text pdf available upon request.

The lab also includes the expertise to employ EKG, skin conductance and impedance cardiography for the non-invasive measurement of peripheral autonomic nervous system activity. Individual differences in ANS activity can be used to evaluate the differential impact of experience.

• Respiratory Sinus Arrhythmia. RSA (also known as high-frequency heart period variation) is a marker of vagal (parasympathetic) control over cardiac activity, and is a valuable measure in models linking physiological, social, and emotion regulation. RSA is assessed through spectral analysis of EKG.
• Pre-ejection Period. PEP, measured using impedance cardiography, is a marker of sympathetic control over cardiac activity. PEP and RSA often are measured together to evaluate simultaneously how the two branches of the autonomic nervous system respond to some stimulus. 
• Galvanic skin response. GSR (skin conductance) is an alternative, non-cardiac marker of sympathetic activity. 

Selected journal articles, abstracts, and online resources:

1. DeCaro JA. 2009. Novel non-invasive alternatives for the measurement of autonomic stress responses in children and adults [abstract]. American Journal of Physical Anthropology 138(S48):116-117.
2. DeCaro JA, Worthman CM. 2008. Culture and the socialization of child cardiovascular regulation at school entry in the US. American Journal of Human Biology 20(5):572-583. View the abstract. Full text pdf available upon request.
3. DeCaro JA, Worthman CM. 2004. State regulation across the generations: children's autonomic arousal and their parents' daily schedules [abstract]. American Journal of Physical Anthropology 123(S38):83.
4. Brown RA, DeCaro JA. 2002. AcqKnowledge application notes: impedance cardiography and pre-ejection period. View the document.

The lab relies on detailed tracking of daily social experience for the social and cultural contextualization of physiology. We also track physical activity patterns throughout the day to determine how daily activity patterns translate into energy expenditure.

•  Daily Life Architecture and PROUST. Using the DLA method, we are able to guide participants through the creation of detailed 24-hour diaries regarding daily activities, behaviors, and experience. DLA diaries are designed not only to record individual events and their frequency, but also to capture the sequencies and contingencies that link events. Equally important, DLA is an ethnographic tool used to identify cultural models as they are enacted in daily life. PROUST is the computer program for Personal Digital Assistants (PDAs) we and collaborators have created to implement the DLA experience tracking approach. 
• Actigraphy. The lab uses small, non-invasive accellerometers worn around the waist to monitor the intesity of physical activity throughout the day. When combined with behavior/experience tracking through the DLA approach, and outcome measures such as body composition, actigraphy provides a powerful means to examine how culture and daily experience combine to influence human energetics.

1. DeCaro JA, DeCaro E, Ashley DH. 2012. Investigating the social ecology of daily experience using computerized structured diaries: Physical activity among Mexican-American young adults. Field Methods 24(3):328-347. View the abstract. Full text pdf available upon request.
2. DeCaro JA, Ashley DH. 2009. Culture, daily routines, and patterns of physical activity among Mexican American residents of West Alabama [abstract]. American Journal of Human Biology 21:250.
3. DeCaro JA, Worthman CM. 2008. Culture and the socialization of child cardiovascular regulation at school entry in the US. American Journal of Human Biology 20(5):572-583. View the abstract. Full text pdf available upon request.
4. DeCaro JA, Worthman CM. 2008. Return to school accompanied by changing associations between family ecology and cortisol. Developmental Psychobiology 50(2):183-195. View the abstract. Full text pdf available upon request.
5. DeCaro JA, Worthman CM. 2007. Cultural models, parent behavior, and young child experience in working American families. Parenting: Science and Practice 7(2):177-203. View the abstract. Full text pdf available upon request.