oxytocin specifically increases trusting, rather than general risk-taking. As with lovers and mothers, the hormone enables animals to take the risk of approaching other members of the species – it ‘links the overcoming of social avoidance with the activation of brain circuits implicated in reward’. It does this partly by suppressing the activity of the amygdala, the organ that expresses fear. If human economic progress has included a crucial moment when human beings learned to treat strangers as trading partners, rather than enemies, then oxytocin undoubtedly played a vital role.