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Proof From Neuroscience That Trusting People Makes Them More Trustworthy

02/05/2012 17:00


Speaking to a business owner recently who had been suffering significant losses as a result of theft by employees, I was quite surprised when at one point he out rightly declared “I don’t trust any of these people working for me. Never have and never will.”

Of course anyone in his position could be forgiven for having trust issues, but to reach the point where you do not trust anyone in the organization – that’s a terrible place to be. But perhaps even worse is that there’s a very strong possibility that the business owner himself could be the cause of this breakdown in trust. The fact that his business is suffering from high employee turnover, low job satisfaction, a general lack of motivation and is losing revenue to boot could be the direct result of this employer’s attitude of never having trusted any of his employees to start off with. Let me explain.

The Trust Hormone

Oxytocin is a neurohormone produced in the brain of all mammals and is known to play a role in various social interactions such as the maternal attachment a mother has with her baby, social recognition, pair bonding between couples, sexual arousal and social bonding. However research headed by Paul J. Zak, neuroeconomist at Claremont Graduate University in Southern California, has shown that oxytocin also plays a significant role in the formation of trust between people.

Wondering how the human brain determines when to trust someone and when not to trust someone, Zak and his colleagues conducted several experiments using students from the University of California as participants. Among others, the participants took part in the Trust Game – an experiment devised to study individuals' propensity to be trusting and to be trustworthy. Participants’ oxytocin levels were then monitored throughout the process.

Response to Being Trusted

The researchers found that when participants felt that they were trusted, their brains responded by producing oxytocin. When the level of trust they were given was increased, their brains produced even more oxytocin. Most significantly however, was that the rise in oxytocin levels then caused these subjects to behave more trustworthy. In other words, people who feel trusted become more trustworthy as a result of increased oxytocin levels in their brains!

To make sure that they were right about oxytocin’s “on-switch” role, Zak collaborated with a research team from the University of Zurich headed by economist Ernst Fehr. They conducted experiments where 200 investors inhaled a dose of oxytocin formulated as a nasal spray to artificially increase their oxytocin levels while playing the Trust Game. Again the results were overwhelming – the “dosed” subjects showed a significant increase in trustworthy behaviour.

Response to Distrust

And what about the opposite – how do people respond when they feel distrusted? Zak and his team discovered that when male participants are distrusted it causes a rise in the levels of a hormone called dihydrotestosterone (DHT). Increased levels of DHT increase the desire for physical confrontation in challenging social circumstances. In other words, men have an aggressive reaction to being distrusted! And if you’re wondering about female’s reaction to distrust – let Zak speak for himself on this one: “We think of women as “cooler” responders, although we do not yet fully know the physiological underpinnings for this difference”.  

 Leadership Implications

You probably don’t need me to say this, but just so we have it on record: Leaders who want to increase trust in the workplace can start off by being trustworthy and by trusting their people more. Of course this doesn’t mean acting oblivious to individuals who clearly cannot be trusted. But it does mean at least giving people the opportunity to prove themselves trustworthy by showing that you trust them. While this may work on a conscious level where people just want to honor your trust, this research shows that it definitely also works on a deeper, neurological level in the human brain. In a team or organization this has the potential to trigger a snowball trust-building effect. Showing people that you trust them rises the oxytocin levels in their brains and that makes them potentially more trustworthy. They then also show more trust in you and that in return rises your oxytocin levels, causing you to be more trustworthy and to show more trust in them. Get the idea?

On the other hand leaders and managers who show constant distrust can trigger a whole sequence of negative responses. At best people will do what they have to and behave in a trustworthy manner simply because they are guided by firm values and moral principles. At worst they could respond with aggression which could manifest in any number of ways, such as sabotaging the organization, spreading discontent or stealing your profit.

  • In my next post I plan to take a closer look at why trust is such a critical determinant of success in the 21st Century workplace. Meanwhile I would appreciate any comments and insights on this article or on trust-related issues in general!


Zak, P. J. (2008). The Neurobiology of Trust 2008. Scientific American, June, 99-95.

Zak, P. J., Kurzban, R., & Matzner, W.T. (2005). Oxytocin is associated with human trustworthiness. Hormones and Behavior 48, 522–527.

Kosfeld, M et al, (2005). Oxytocin Increases Trust in Humans. Nature, 435, 673–676.

Leave a Comment:

Trust and difference

Peggy 19/01/2013
I'm wondering if you've made connections with your work on brain and managing diversity in the workplace (US and global). Seems to explain a lot about why people who are different (culture, gender, generation) have a more difficult time progressing - majority members may have a "foe" reaction to them, not understand social cues, etc. Also, explains why the seemingly insignificant banter or socializing that happens naturally with those who have sameness is so powerful (all that oxytocin). This bonding would need to be actively nurtured with those who are different, or trust won't develop. This suggests that diverse teams/pairs will underperform unless they actively overcome the instinct to distrust those who are different.
I'm also interested in whether you have connected cultural miscues with brain function and performance.
Appreciate your work and insights!

oxytocin and trust

miles penfold 02/05/2012
fascinating, I can say from 1st hand experience that trusting my hospital staff of 40 to do their best and supporting them in that capacity resulted in a myriad of positive spin offs, including increased productivity and zero theft. Obviously there are multiple other factors that could contribute to this but establishing trust with my staff was the single most important factor I can identify in turning the morale around in that place. Obviously I trust them to get on with the job at hand they trust me to represent them at higher levels etc etc.

Re: oxytocin and trust

Manie 03/05/2012
Thanks for sharing that, Miles, it is a great and inspiring real-life example of how trust builds trust! Clonidine Toprol XL Topamax