The neural mechanisms by which testosterone acts on interpersonal trust

Area of Science:

• Neuroscience
• Social Psychology
• Endocrinology

Background:

• Testosterone is known to reduce interpersonal trust in humans.
• The precise neural mechanisms underlying this effect remain largely unknown.
• Previous hypotheses suggest testosterone may increase social vigilance via amygdala-neuropeptide systems.

Purpose of the Study:

• To investigate the neural mechanisms by which testosterone affects trust.
• To examine the impact of testosterone on brain connectivity during social judgments.
• To explore the role of the amygdala and orbitofrontal cortex (OFC) in testosterone-modulated trust.

Main Methods:

• A placebo-controlled study administering testosterone to 16 young women.
• Utilizing functional magnetic resonance imaging (fMRI) to measure brain activity and connectivity.
• Assessing judgments of facial trustworthiness and associated neural responses.

Main Results:

• Testosterone administration decreased functional connectivity between the amygdala and OFC during evaluations of unfamiliar faces.
• Increased amygdala responses were observed specifically towards faces rated as untrustworthy.
• Connectivity between the amygdala and brain stem was not significantly affected by testosterone.

Conclusions:

• Testosterone may reduce trust by decoupling the OFC and amygdala, potentially via a prefrontal-dopaminergic mechanism.
• This decoupling could lead to heightened amygdala vigilance towards untrustworthy social cues.
• Findings offer neurobiological insights into how testosterone influences social decision-making and trust.