This post is also available in Dutch.
For some people, trust is easily given, while for others, it’s locked in a box and hidden away. What parts of our brains are important for trust?
One of my favorite team-building activities is the ‘trust fall.’ Blindly falling into the arms of a bunch of people is fun! Worst-case scenario: You hit the floor. However, actually placing your trust, confidence, and certainty in someone else—whether they be a stranger or a romantic partner—is an entirely different story and requires greater prudence. The ease with which one person begins to trust another is influenced by personal experience. Our own stories profoundly shape the way we perceive the world, the people around us, and their actions. Though subjective and intangible, interpersonal trust is a concept that neuroscientists have been working to disentangle for over a decade.
Oxytocin is a hormone often linked with feelings of love and trust. Researchers recently tested how it affects willingness to trust by giving a dose of either the hormone or a placebo to their subjects. In a game where participants invest virtual money to measure their trust, subjects with the hormone were less able to learn. In the hormone group, oxytocin promoted unjustified trust as well as distrust. MRI scans showed that subjects who were given oxytocin had less activity in brain areas associated with reward and learning. Thus, oxytocin may affect trust by lessening the brain’s ability to predict actions and change pre-existing beliefs (i.e., reinforcement learning), thus impacting both trust and distrust.
Neuroscientists have also observed that trust seems to work differently in men and women. A study on sex differences in the neural development of trust compared men to women (16-27 years old) in a game that featured cooperation with a partner who was either fair or unfair. The results show mostly stable patterns of trust and social reciprocity from mid-adolescence to early adulthood. Men showed more basic trust than women at the beginning of the game. However, sex differences in trust increased with age. Males reacted more strongly to unfair treatment in the game than did females and this effect became more pronounced with age. Older male participants were more quick to distrust than older female participants.
Trust is not only important in society and interpersonal relationships, but also in psychiatric disorders. Healthy adults usually reciprocate trust if trust is given; they will trust in response to trust from their partners and decrease their trust if their partner’s trust also decreases. In mental illnesses, like schizophrenia or borderline personality disorder, the ability to develop and maintain trust is often impaired. Individuals with damage to a brain area called the insula, important for recognizing social norms and evaluating risk in decision-making, display abnormal amounts of trust. Neuroimaging studies have found that many areas of the brain—and communication between those areas—can be predictive of a person’s trust behavior.
From genetics to our personal life experiences, there are numerous factors that explain how easily someone may trust or distrust another person, as well as how we mentally build, maintain, and/or repair trust in someone else. Indeed, interpersonal trust is quite complex—certainly more enigmatic than the trust fall.