Do Testosterone and Cortisol Jointly Relate to Adolescent Dominance? A Pre-registered Multi-method Interrogation of the Dual-Hormone Hypothesis

Objective: The goal of the present study was to extend the findings of the dual-hormone hypothesis (DHH) literature by assessing whether the interaction between testosterone (T) and cortisol (C) is associated with dominance in an adolescent sample via multiple methods of measuring T, C, and dominance, and with pre-registration of hypotheses and analyses. Methods: In a sample of 337 adolescents (M_age = 14.98, SD = 1.51; 191 girls) and their caregivers, hormonal assays were obtained from hair and saliva, and dominance behavior was assessed across four operationalizations (behavioral ratings in a leadership task, self- and caregiver reported dominance motivations, and self-reported social potency). Results: T and C main effects were generally null across hormone and dominance operationalizations, except that observer-rated dominance was negatively associated with salivary T, and social potency was positively associated with salivary T and negatively associated with salivary C. Support for the DHH was weak. Point estimates reflected a small negative T × C interaction for behavioral ratings of dominance, consistent with the DHH, whereas interaction effects for report-based dominance measures were close to zero or positive. Conclusions: The results contribute to a growing evidence base suggesting T × C interaction effects are variable across measures and methods used to assess hormones and dominance and highlight the need for comprehensive, multi-method examinations employing best practices in scientific openness and transparency to reduce uncertainty in estimates. Measurement of hormones and dominance outcomes vary across labs and studies, and the largely null results should be considered in that context.