The Conundrum of the Laboratory: Challenges of Assessing Preschool-Age Children’s Salivary Cortisol Reactivity

Abstract

The laboratory assessment of young children’s cortisol reactivity is a major obstacle in psychoneuroendocrine research. The current study aimed to test the effectiveness of a developmentally-appropriate stressor paradigm in the laboratory with a sample of 152 preschool-age children. Salivary cortisol samples were obtained at 30 min after arrival to the laboratory and at 20, 30, 40, and 50 min post-stressor. Observations of children’s positive emotions (PE) and negative emotions (NE) were coded to assess children’s behavioral response to the paradigm. Children’s mean growth curve evidenced a significant linear decrease in cortisol values from baseline to 20 min post-stress and a leveling off by 40 min post-stress. However, when taking into account children’s individual differences in the timing of peak cortisol response, we observed a significant increase in cortisol from children’s baseline sample to their peak post-stressor sample. Moreover, children’s PE significantly decreased and NE significantly increased during the stressor, providing further support for the validity of the stress-inducing nature of the paradigm. Additionally, children’s PE and NE during the task were significantly associated with individual differences in their cortisol responses. Our findings highlight the challenges for neuroendocrine researchers with respect to obtaining mean increases in preschoolers’ cortisol reactivity in the laboratory and have important methodological implications, particularly regarding the importance of collecting multiple post-stressor samples.