While wilderness programs are recognized as a feasible intervention to promote psychological independence in adolescence, little is known about physiological changes. The present study focused on oxytocin, a key hormone for social cognition and behavior, and investigated changes in OT concentrations during a wilderness program among adolescents. Twenty-one 4th-7th graders were separated from parents and immersed with adventures and challenges in the woodlands of Motegi, Tochigi Prefecture, Japan for 31 days, and dataset of 20 boys aged 9-13 years-old were used for analysis. OT concentrations in early morning saliva samples on days 2, 5, 8, 13, 18, 20, 21, 22 and 30 were determined using ELIZA. We performed multi-level regression analyses to compare the OT concentrations before and after solo and team-based survival challenges, and across the nine observational points, adjusting for potential covariates. We found that adolescents increased OT level in a situation where they needed others' cooperation and support for survival (coefficient: 2.86, SE: 1.34, p = 0.033). Further, we found that adolescents gradually decreased their basal OT level during a long separation from parents (coefficient: -0.083, SE: 0.034, p = 0.016). A combination of these findings suggest the OT level may be a marker for psychological independence.
Keywords: Japan; adolescents; child; independence; nature; oxytocin.