An invisible glue

A sprained ankle, a bump on the back of the head or a bruised wrist: If she’s to emerge unscathed, Tanja Ulrich, a doctoral student trained in biomedicine, needs to have a lot of trust in her dance partner. Especially since much of the routine seems to involve her being hoisted by the hips, swung over her partner’s back and balancing on their shoulders.

“Dancing can be a risky business!” she says with a laugh. Ulrich works with Emily Cross, ETH Professor of Cognitive and Social Neuroscience and a specialist in a field of study known as embodiment. Like many of her colleagues in the group, Ulrich also dances as a pastime. When she talks about risk, however, she means much more than just throwing a few breakneck moves. “You have to give a lot of yourself,” she explains. “If I place my trust in another person and count on them to accept me, and to engage with me, I automatically make myself vulnerable.”

For Gudela Grote, Professor of Work and Organizational Psychology at ETH Zurich, this unguarded state is a key element of trust: “It puts us in a place of vulnerability.” A whole range of disciplines have attempted to fathom this sphere – philosophy, psych­ology, neuroscience, sociology, cultural the­ory. In essence, all are seeking to grasp the remarkably slippery phenomenon of interpersonal trust. Love is perhaps the best analogue here: we all know intuitively what it is, and we use it to explain certain feelings or situations. But when it comes to understanding and defining it in all its manifold complexity – things suddenly become a little more difficult.

Trust as a concept crops up in a whole range of disciplines, says Grote: “It is often described as the glue that holds relationships together.” That said, it’s not so easy to prove this empirically – essentially because of an inability to measure trust in any meaningful way. Denis Burdakov, Professor of Neuroscience at ETH, agrees: “I think we don't yet have a good way to measure trust concurrently with neural activity.”

Money on trust

Just over 20 years ago, the US neuroeconomist Paul Zak published the results of a clinical trial called “The neurobiology of trust”. Participants were required to transfer money to an unknown partner via computer. They did so in the knowledge that the amount they transferred would then be tripled – to the benefit of the recipient – but that their original transfer might never be repaid. The trial showed that the greater the amount of money received, the higher the level of oxytocin (a neurotransmitter also known as the “love hormone”) that was measured in the recipient’s blood. By the same token, the higher the level of oxytocin in the recipient’s blood, the greater the probability that the money would be returned. In a follow-up experi­ment conducted with students in Zurich, Zak was able to show that participants who had previously received three shots of oxytocin in the nasal cavity demonstrated greater trust when making their cash transfer.

Surely these findings are fairly conclusive? Organisational psychologist Grote smiles and cautions that some researchers are unhappy with Zak’s methodology, and many find it reductionist. “When I drink alcohol, I’m also more inclined to trust other people,” Grote says. “Context is critical for whether I trust people or not. Do they make it easy for me to trust them, in that they are honest and dependable? Or if I’m already feeling stressed, am I perhaps reluctant to make myself even more vulnerable by trusting others?”

Here, Grote draws on the economist’s transactional understanding of trust. In this case, trust is primarily a question of assessing the likelihood of a favour or service being returned. For Ulrich, what we see here is an “emotional quid pro quo”: acceptance and engagement in exchange for attention; vulnerability in exchange for openness and transparency. In other words, trust is more than just a social glue. It’s also a means of collaboration.

Evidently, too, there’s more to trust than a digi­tal transfer of cash in a lab setting. When it comes to building trustful relationships with a business partner or your boss, there’s no fast-acting hormone spray to hand. Even oxytocin enthusiast Paul Zak now acknowledges that physical cues such as looks and behaviour play an equally important role. That’s why people from the same cultural sphere find it easier to trust one another, says Grote. From this perspective, the function of stereotypes is to scale up trust to the level of society as a whole.