Hormones affect human physical functions, behaviour and mental well-being, with testosterone, a primary androgen hormone, playing a vital role in shaping male social cognition and behaviour. A research team of The Hong Kong Polytechnic University (PolyU) has conducted interdisciplinary research to uncover the neurocognitive correlates of testosterone in the brain function of young men, and their impact on social behaviour. The findings provide valuable insights into potential applications of testosterone therapy in clinical and mental healthcare.
The research team is led by Prof. Yin WU, Associate Professor of the PolyU Department of Applied Social Sciences. By administering a single dose of testosterone or placebo gel to healthy young men who participated in the experiments and comparing their performance in assigned tasks, the team investigated the correlation between testosterone levels and various behavioural traits such as generosity, state self-esteem, sensitivity to angry facial expressions, aversion to inequality, prosocial learning and aggression.
High testosterone may lead to increased selfishness
Their first study focused on the impact of testosterone on socio-economic behaviour. The researchers combined pharmacological manipulation and functional magnetic resonance imaging (fMRI) to discover how testosterone influences generosity and the underlying neural mechanisms. They evaluated the experimental subjects' performance in a social discounting task, in which participants chose between benefiting only themselves and providing also some benefit to another person at a particular social distance, while also observing their brain activity through fMRI during the decision-making process.
Findings revealed that exogenous testosterone administration reduced generosity, particularly when interacting with more distant others. Additionally, the fMRI results showed that higher testosterone levels are linked to reduced neural activity in the temporoparietal junction (TPJ), an upper brain region associated with social cognition. The team suggested that testosterone may reduce concern for others' welfare at the neural level by dampening activity in the TPJ, highlighting a correlation between increased testosterone levels, and selfishness and reduced empathy in economic decision-making.
Prof. Wu said, "The role of hormones in human cognition is a growing research focus in psychology and neuroscience. Leveraging cutting-edge neuroimaging facilities, we have been able to make new discoveries in this area. However, key questions remain, such as how testosterone affects economic decision-making or how the stress hormone cortisol shapes social preferences like altruist behaviour. Our team is investigating these complex dynamics to drive impactful outcomes."
The research, conducted in collaboration with scholars from Peking University, Shenzhen University, South China Normal University and University of Zurich, was published in Proceedings of the National Academy of Sciences (PNAS). In recognition of his excellent work in this ground-breaking research, Prof. Wu has been honoured with the Second-class Award under the 9th Higher Education Outstanding Scientific Research Output Awards (Humanities and Social Sciences) by the Ministry of Education of China.
Increased testosterone levels help boost state self-esteem updating
In another related study, the team explored the link between state self-esteem (SSE), a momentary sense of self-worth and perceived social status, and testosterone levels. Experimental subjects were asked to complete a social evaluation task in which they adjusted their predictions of potential evaluation by others, while dynamically reporting their SSE based on the social feedback they received. The researchers then applied a computational modelling approach to investigate the dynamic changes in their SSE throughout the process.
Persistent low SSE may induce aberrant behaviours and increase the risk of psychiatric conditions such as anxiety, depression and eating disorders. From a clinical perspective, low SSE in individuals with schizophrenia has also been associated with heightened self-aggression. The team found, however, that testosterone administration can boost SSE updating and alleviate these behaviours.
Pharmacological studies have demonstrated that testosterone replacement therapy can significantly improve such aberrant behaviours, but chronic use may carry side effects. This research has provided valuable clinical insights in this regard, indicating that a single dose of testosterone can positively influence SSE, particularly in positive social environments. It is suggested that future clinical practice consider combining exogenous testosterone with behavioural interventions that foster supportive environments and social feedback to enhance SSE as a potential pre-clinical treatment for relevant aberrant behaviours and clinical symptoms.
Prof. Wu remarked, "By combining computational modelling with behavioural pharmacology, we have uncovered the psychological mechanisms through which testosterone affects complex social processes. We envision that these findings could inform public organisations in developing public health policies and strategies that foster positive community environments and promote mental health and well-being."
Prof. Wu's team collaborated with scholars from East China Normal University, University of California San Diego and University of Zurich in the research. The findings were published in the international journal Biological Psychiatry: Cognitive Neuroscience and Neuroimaging.
Looking ahead, Prof. Wu and his team will continue to advance research into the implications of testosterone on social cognition and brain activity in young men, laying the foundation for future studies in this field, and further promoting the translation of the research outcomes into practical application. He is presently partnering with the PolyU Department of Aeronautical and Aviation Engineering to investigate the influence of hormones on pilot flying performance and the underlying brain mechanisms, thereby supporting airlines in developing effective strategies for recruiting and training cadet pilots.
