Culture, Infancy, and the Milieu Intérieur

• In Event: 2-127 - New Directions in Research on Culture and Emotion Regulation

Integrative Statement

Developmental research is often concerned with the “environment,” usually referring to the external social or physical world of a child’s daily life, or to some specific configuration of stimuli, often experimentally imposed, which elicit a response. There has been little attention, however, to the milieu intérieur as described by the 19th-century physiologist Claude Bernard. Literally the “internal environment,” Bernard’s concept focuses on the body’s extra-cellular environment and homeostatic regulation, which enable an organism to function effectively in a variety of environments. Given the known importance of (external) environments for early development, and given the increasingly evident differences among cultural groups in daily environment, it seems appropriate to examine possible differences among groups in infants’ milieu intérieur.
Indexing the HPA axis – a key regulator of the internal environment -- with (salivary) cortisol, the present study reveals significant variation in mean basal cortisol level among infants from five different cultural groups. The data are derived from the International Baby Study, utilizing samples from middle-class families in Padua, Italy (n=42); Daejeon and Incheon, Korea (n=13); Bloemenheim, the Netherlands (n=26); Seville, Spain (n=27); and eastern Connecticut, U.S.A. (n=32). Infant saliva was obtained using an absorbent swab (Salimetrics, Carlsbad, CA) four times on each of two consecutive days, when the babies were 2 and 6 months of age. In addition, cortisol was measured for two days at about 2 weeks, and before and after their first bath (about the same time). Saliva samples were shipped frozen and assayed at the Institute for Interdisciplinary Salivary Bioscience Research at the University of California, Irvine, using a commercially available enzyme immunoassay (Salimetrics, Carlsbad, CA). The resulting values were subjected to a natural log transformation for statistical analysis.
Preliminary analysis of the bath data from two samples indicates that at 2 weeks of age the US babies experienced twice the level of cortisol, averaged across the day, as did the infants from Spain (Figure 1; MUS = 0.47 ug/dL; MES = 23 ug/dL; p = .03). At 2 months, this contrast was evident as well among the other cultural groups in the first morning sample (about 1 hour after waking; p<.05). The Italian, Spanish, and Dutch means are grouped closely together at about .28 ug/dL, and the Korean and U.S. results both lie near .50 ug/dL. Results at 6 months are similar (overall p <.01), but with a somewhat greater spread in the lower cluster. At both ages and in all samples, means declined over the course of the day, with the slope sharper in the US-Korean group than in the Italian-Spanish-Dutch one (p<.05).
Discussion will focus on differences in the infants’ developmental niche in the five cultural settings (Super & Harkness, 1986); on how these may influence HPA activity and “adaptive calibration” (Del Giudice, Hinnant, Ellis, & El-Sheikh, 2012); on implications for comparative studies of the stress response; and on possible influences on later health and development.

Authors

• Charles M. Super, University of Connecticut
  Presenting Author

• Douglas Granger, University of California, Irvine
  Non-Presenting Author

• Ughetta Moscardino, University of Padova
  Non-Presenting Author

• Blanca Huitron, National Autonomous University of Mexico
  Non-Presenting Author

• Marjolin J.M. Blom, Raad voor Volksgezondheid en Samenleving
  Non-Presenting Author

• Jong-Hay Rha, Hannam University
  Non-Presenting Author

• Sara Harkness, U. of Connecticut
  Non-Presenting Author