For the hormone data, one participant had blood contamination in the saliva sample, one participant did not provide sufficient saliva sample, and four participants had hormone data differed by more than three standard deviations from the normalized means. At exactly 20 min after the finishing of the Tetris competition (t40), participants provided a second saliva sample and then completed the decision-making tasks. After completing the competition and revealing the winner and loser (t20), participants viewed a neutral video clip (a documentary about Ireland, serving as filler task) in their own test rooms while doors being closed again. Following the competition, participants completed the PANAS again, and the WTP, IAT and UG tasks described above. Testosterone, often dubbed the 'dominance hormone', has been linked to status-seeking behavior. A recent study suggests that testosterone plays a pivotal role in this universal social phenomenon. Moreover, individual differences in testosterone sensitivity could also influence the hormone's effect on empathy. While it might be surprising to some, testosterone levels have been found to significantly influence this trait. Let's explore a few scenarios where testosterone's influence on brain sensitivity to social cues can be observed. High testosterone levels can also disrupt social bonds by enhancing individuals' sensitivity to perceived threats to their social status, leading to increased aggression and conflict. For mammals living in multimale groups, aggression is hypothesized to link male social status (i.e. dominance rank) and testosterone levels, given that high status predicts mating success and is acquired partly through aggressive intragroup competition. We assert that aggression rates are insufficient to explain links between dominance rank and testosterone levels in male chimpanzees and that other social variables (e.g. male–male relationship quality) may regulate testosterone's links to aggression. In the present study, we test both aggression levels and lean muscle mass, as measured by urinary creatinine, as links between dominance rank and testosterone levels in a large sample of wild male chimpanzees. The study used a double-blind, placebo-controlled design, meaning neither the participants nor the researchers knew who received the real hormone. Men’s self-esteem, in particular, may be more sensitive to changes in social status or perceived rejection. The study also opens the door to potential new treatment strategies that combine hormonal and behavioral approaches to boost mental health. There were 4 trials for each of the offer levels (£1/£9, £2/£8, £3/£7, £4/£6, £5/£5 – in this notation, the number before the slash denotes the amount offered to the participant and the number after the slash denoted the amount allocated to the proposer). During each trial, participants viewed sequentially a photograph of the proposer (1,000 ms), and the amount of the offer (until response). Half of the participants did the seven blocks in the order presented previously; to control for the order effect, Blocks 2, 3, and 4 were swapped with Blocks 5, 6, and 7 for the other half of the participants. In the reversed target-stimuli discrimination task (Block 5, 20 trials), Block 2 was repeated with a switch of the categorization keys by pressing left key when a lower-status product appeared on the screen and a right key when a higher-status product appeared. In the attribute discrimination task (Block 1, 20 trials), participants were asked to press a left key when a positive word appeared on the screen and a right key for a negative word. The IAT followed the procedure designed by Greenwald et al.16, involving two target categories (higher-status vs. lower-status products) and two attribute categories (positive vs. negative). Note that we didn’t use British university souvenirs since our participants were from a prestigious British university, and thus potentially confounding their responses.
