Testing the influence of testosterone administration on men's honesty in a large laboratory experiment

Revisiting the Relation Between Steroid Hormones and Unethicality in an Exploratory, Longitudinal Study With Female Participants

Research on the relation between hormones and unethical behaviors and tendencies has provided mixed results, hindering the understanding of the potential biological regulation of unethical behaviors and tendencies. We conducted an exploratory, longitudinal study (N = 257 women) allowing to estimate relations between, on the one hand, steroid hormones (testosterone, cortisol, estradiol, and progesterone) and conception probability and, on the other hand, a broad variety of measures related to unethicality (self-reported personality variables, cheating in committed relationships, self-serving economic dishonesty in a behavioral task, namely, the mind game). Contrary to theoretical assumptions of and results from some previous studies, we find no consistent relation between hormones and unethical behavior or tendencies in the majority of analyses. Yet, some small, exploratory associations emerged that call for (preregistered) replications, before more firm conclusions can be made.

Testosterone eliminates strategic prosocial behavior through impacting choice consistency in healthy males

Humans are strategically more prosocial when their actions are being watched by others than when they act alone. Using a psychopharmacogenetic approach, we investigated the endocrinological and computational mechanisms of such audience-driven prosociality. One hundred and ninety-two male participants received either a single dose of testosterone (150 mg) or a placebo and performed a prosocial and self-benefitting reinforcement learning task. Crucially, the task was performed either in private or when being watched. Rival theories suggest that the hormone might either diminish or strengthen audience-dependent prosociality. We show that exogenous testosterone fully eliminated strategic, i.e., feigned, prosociality and thus decreased submission to audience expectations. We next performed reinforcement-learning drift-diffusion computational modeling to elucidate which latent aspects of decision-making testosterone acted on. The modeling revealed that testosterone compared to placebo did not deteriorate reinforcement learning per se. Rather, when being watched, the hormone altered the degree to which the learned information on choice value translated to action selection. Taken together, our study provides novel evidence of testosterone's effects on implicit reward processing, through which it counteracts conformity and deceptive reputation strategies.

The association between testosterone and unethical behaviours, and the moderating role of intrasexual competition

Researchers have called for a greater use of neuroscientific methods to advance theories in ethical behaviour. Our research takes a neuroscientific approach to investigating unethical behaviour by examining the roles of testosterone and intrasexual competition. We propose that unethical behavioural intentions will be greater for high-testosterone individuals in response to highly intrasexually competitive situations as a means of enhancing status. In an experiment, we measure baseline testosterone and assign participants to an intrasexually competitive or control condition. We demonstrate that in men, but not in women, testosterone is positively associated with unethical behavioural intentions in response to an intrasexual competition prime. Furthermore, using textual analysis, we find that testosterone is positively associated with the usage of anger-related words in response to an intrasexual competition prime among men. In turn, anger-related words are positively associated with unethical behaviour, suggesting that anger may play a role in motivating high-testosterone men to behave unethically. Overall, our findings contribute to the literature by suggesting that testosterone and competition lead to greater unethical behaviour in men, and that anger plays a role in promoting unethical behaviour.

The effect of testosterone on economic risk-taking: A multi-study, multi-method investigation

Testosterone has been suggested to influence individuals' economic decision making, yet the effects of testosterone on economic behavior are not well-understood and existing research is equivocal. In response, in three studies, we examined the extent to which testosterone affected or was associated with several different facets of economic decision making. Study 1 was a double-blind, placebo-controlled, within-subjects study examining loss aversion and risk-taking (N = 26), whereas Study 2 was a larger double-blind, placebo-controlled, between-subjects study examining loss aversion and risk-taking behavior (N = 117). As a methodological compliment, Study 3 was a larger correlational design (N = 213) with a highly accurate measure of endogenous testosterone examining a wider range of economic behaviors and trait-like preferences. Broadly, the results of all three studies suggest no consistent relationship between testosterone and financial behavior or preferences. Although there were significant effects in specific cases, these findings did not replicate in other studies or would not remain significant when controlling for family-wise error rate. We consider potential contextual moderators that may determine under what circumstances testosterone affects economic decision making.

The pivotal role of heme Oxygenase-1 in reversing the pathophysiology and systemic complications of NAFLD

The pathogenesis and molecular pathways involved in non-alcoholic fatty liver disease (NAFLD) are reviewed, as well as what is known about mitochondrial dysfunction that leads to heart disease and the progression to steatohepatitis and hepatic fibrosis. We focused our discussion on the role of the antioxidant gene heme oxygenase-1 (HO-1) and its nuclear coactivator, peroxisome proliferator-activated receptor-gamma coactivator (PGC1-α) in the regulation of mitochondrial biogenesis and function and potential therapeutic benefit for cardiac disease, NAFLD as well as the pharmacological effect they have on the chronic inflammatory state of obesity. The result is increased mitochondrial function and the conversion of white adipocyte tissue to beige adipose tissue ("browning of white adipose tissue") that leads to an improvement in signaling pathways and overall liver function. Improved mitochondrial biogenesis and function is essential to preventing the progression of hepatic steatosis to NASH and cirrhosis as well as preventing cardiovascular complications.

Testosterone administration in human social neuroendocrinology: Past, present, and future

Over the past 20 years, social neuroendocrinology researchers have developed pharmacological challenge paradigms to assess the extent to which testosterone plays a causal role in human psychological and behavioural processes. The current paper provides a brief summary of this research and offers recommendations for future research examining the neuroendocrine mechanisms underlying human behaviour.

The role of oxytocin on self-serving lying

INTRODUCTION

The effects of intranasal administration of the neuropeptide oxytocin on social cognition and behavior are highly specific. Potentially situational and personal variables influence these effects. The aim of the present study was to investigate effects of oxytocin administration on self-serving lying, including situational effects.

METHODS

A total of 161 adult males participated in a randomized double-blind placebo-controlled between-subject intranasal oxytocin administration (24 international units) study. Self-serving lying was assessed using three subsequent rounds of the die-in-a-cup paradigm, in which different degrees of lying can be implemented by the participants that can be determined on group level.

RESULTS

Oxytocin administration seemed to promote self-serving lying, particularly in the third (last) round and only to a certain degree (not to the maximum possible).

CONCLUSIONS

Our findings demonstrate that oxytocin administration can promote self-serving lying when given repeated opportunities to lie. Moreover, exploratory results presented in the Supplementary Material indicate that the sensitivity to the effects of intranasal oxytocin in this domain might be moderated by individual differences in the oxytocin receptor gene.

Testosterone administration increases social discounting in healthy males

Although testosterone is thought to induce antisocial and aggressive behavior, research on social economic interactions has associated it with prosocial and affiliative behavior. Here, we investigated the effects of testosterone on social distance-dependent generosity in an economic discounting task where participants chose between selfish and generous alternatives. We administered testosterone gel or placebo to men in a double-blind, randomized design and measured how willing they were to share rewards with close and distant others. Across two studies (total n = 174), testosterone administration consistently increased social discounting, that is participants became more selfish, particularly with regard to distant others (vs. close others). This effect was not explained by testosterone-induced increases in social distance perception. Our findings provide causal evidence that-testosterone reduces generosity in human economic decision-making. Moreover, they suggest that the valuation and the perception of social distance are independently affected by testosterone.

Does testosterone impair men's cognitive empathy? Evidence from two large-scale randomized controlled trials

The capacity to infer others' mental states (known as 'mind reading' and 'cognitive empathy') is essential for social interactions across species, and its impairment characterizes psychopathological conditions such as autism spectrum disorder and schizophrenia. Previous studies reported that testosterone administration impaired cognitive empathy in healthy humans, and that a putative biomarker of prenatal testosterone exposure (finger digit ratios) moderated the effect. However, empirical support for the relationship has relied on small sample studies with mixed evidence. We investigate the reliability and generalizability of the relationship in two large-scale double-blind placebo-controlled experiments in young men (n = 243 and n = 400), using two different testosterone administration protocols. We find no evidence that cognitive empathy is impaired by testosterone administration or associated with digit ratios. With an unprecedented combined sample size, these results counter current theories and previous high-profile reports, and demonstrate that previous investigations of this topic have been statistically underpowered.

Testosterone reduces the threat premium in competitive resource division

Like other animals, humans are sensitive to facial cues of threat. Recent evidence suggests that we use this information to dynamically calibrate competitive decision-making over resources, ceding more to high-threat individuals (who appear more willing/able to retaliate) and keeping more from low-threat individuals. Little is known, however, about the biological factors that support such threat assessment and decision-making systems. In a pre-registered, double-blind, placebo-controlled, cross-over testosterone administration study ( n = 118 men), we show for the first time that testosterone reduces the effects of threat on decision-making: participants ceded more resources to high-threat (versus low-threat) individuals (replicating the 'threat premium'), but this effect was blunted by testosterone, which selectively reduced the amount of resources ceded to those highest in threat. Thus, our findings suggest that testosterone influences competitive decision-making by recalibrating the integration of threat into the decision-making process.