Fig. 2

Hormone changes after masturbation with visual stimulus, only visual stimulus and passive setting. Figure 2A-F show the raw data (bullets), individual fits (dotted lines) and the population fits (solid lines) for each measure and grouped by activity (A: Total Testosterone concentration; B: Free Testosterone concentration; C: Cortisol concentration; D: Ratio of Testosterone/Cortisol; E: Ratio of Free Testosterone/Testosterone; F: Ratio of Free Testosterone/Cortisol). With all concentrations, both trigonometric terms are consistently required in the corresponding linear mixed effect models (\(\text{p}<0.01\) respectively, \(\text{F}\) statistics). The polynomial term in the models of the ratios likewise is indispensible (\(\text{p}<0.001\) respectively, \(\text{F}\) statistics). All significant differences were marked with #. Abbreviations: Active = masturbation with visual stimulus; C= Cortisol; FT = free testosterone; ln = logarithm; min: minutes; ng/ml = nanogram/millilitre; P = participant (P1 =participant 1 etc.); Passive: no masturbation and no visual stimulus; TT = total testosterone; Visual: visual stimulus without masturbation