Introduction
anxiety
Across many vertebrate species, testosterone regulates energy distribution and promotes investment into mating efforts in a variety of ways [Roney and colleagues [Lopez et al. [All social evaluative interactions involve stressful components, and courtship in particular may cause significant apprehension during courtship interactions [Cortisol is a glucocorticoid hormone released by the hypothalamic-pituitary-adrenal (HPA) axis in response to stress as part of its broader role as a physiological regulator of blood pressure, metabolism, and energy mobilization [There is already some indirect evidence for the role of the HPA axis in human courtship, as displayed by cortisol increases that could reflect anxiety or apprehension before or during opportunities for courtship [It remains unclear overall how stress during courtship and subsequent increases in cortisol may interfere with or trigger other physiological and psychological responses to courtship [see It is currently uncertain whether cortisol responses are generally associated with specific courtship behavior patterns, or whether the association is an effect that is strictly mediated by motivation, cognition, or individual differences in personality or relationship status. Further, anxiety itself may drive the physiological responses of testosterone, in addition to its effects on cortisol. The effects of stress on testosterone may depend specifically on the type of social stress induced and may mediate the relationship between individual differences and behavior. For example, Crowley et al. [The goal of the present study was to investigate testosterone and cortisol responses to social interactions with opposite-sex individuals in both men and women, with or without a prior exposure to psychosocial stress. Primary a priori hypotheses involved the effects of social interactions with opposite-sex individuals on testosterone in men and women, and we explored these hypotheses using two different psychosocial tasks. The first was a non-stressful social interaction task with an opposite-sex individual, which all participants experienced. The second was a psychosocial stress task that half of the participants experienced prior to their non-stressful social interaction with an opposite-sex individual. First, we predicted that we would replicate findings of increases in testosterone for both male and female participants during brief interactions with opposite-sex individuals. This increase would be expected specifically for individuals who have 