Assessing dominance is important for effective social interactions, and prior research suggests that testosterone is associated with men's dominance perceptions. The present study tested for a causal effect of exogenous testosterone on men's sensitivity to vocal cues of other men's dominance, an important parameter in male-male competition across species. One hundred and thirty-nine Chinese men received a single dose (150 mg) of testosterone or placebo gel in a double-blind, placebo-controlled, between-participant design. Participants reported their own dominance and judged other men's dominance from voices. Men's dominance sensitivity was significantly weaker in the testosterone group compared to those in the placebo group.Moreover, men's dominance sensitivity was negatively associated with their self-reported dominance in our Chinese sample, consistent with findings from Western populations. These results indicate that exogenous testosterone has a causal effect in decreasing men's dominance sensitivity, consistent with the Challenge Hypothesis, suggesting that the fluctuation of testosterone concentration mediates individuals' behaviors. Additionally, the present study could motivate further work on vocal assessment in the context of competition in humans and other species.

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Objective: The aim of this study was to acquire the SUVs for each segment of the vertebral body to explore the rationale for the large variability of the SUVs in normal vertebrae.Methods: This retrospective study was performed using the images and data from 39 cancer patients who underwent bone SPECT/CT scans with Tc-99m MDP. The SUVmax and SUVmean of the anterior, middle, posterior; left, middle, right; top, middle, and lower of the lumbar vertebrae 1~5, were calculated. The continuous variables were represented by the median values (Q1,Q3), and the differences among various segments were analyzed by Friedman's nonparametric test. The pairwise comparison between groups was corrected by the Bonferroni method. The P<0.05 was considered statistically signifi cant.Results: In this study, 39 patients (31 women and 8 men; mean age, 54.79±9.12 years; age range, 39-71 years) were elucidated. The SUVmax of the L1 and L3 vertebral bodies' parts were signifi cantly different from those of the other portions of the same lumbar vertebra. The SUVmax of the lower posterior portion of the L1 vertebral body was signifi cantly different from that of the upper posterior portion. There were signifi cant differences in the SUVmax between the upper and lower portions, middle and lower portions in the middle of the L3 vertebral body. The SUVmean of the lower posterior portion of L1 and L2 vertebral were signifi cantly different from those of the upper posterior portion. There were signifi cant differences in the SUVmean between the upper and lower portions of the middle of the L3 vertebral body. There were signifi cant differences among the SUVmax and SUVmean of the right, and middle of the vertebral body except for the L2 vertebral body. There were signifi cant differences among the SUVmax and SUVmean of the anterior, middle segments of the lumbar vertebrae body, and the SUVmax of the anterior and posterior parts of the L2 vertebral body, and the SUVmean of the middle and posterior parts of the L1 vertebra. The SUVmax of the middle and posterior portions of the L3～L5 vertebral body, and the SUVmean of the L1 ～L3, and L5 lumbar vertebrae had signifi cant differences. Conclusion:The difference in the bone metabolism of the lumbar vertebral body is caused by the variation in the horizontal direction of the vertebral body. The bone metabolism in the vertical direction of the lumbar vertebrae has more uniformity. As a quantitative imaging measure, the SUVs might require standardization with adequate reference data to minimize the variability in the participants.

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