Negative Emotions Make It Harder To Trust Others, A New Study Says

Alexey Kuzma/Stocksy

Trust, you're most likely aware, can be difficult to establish, no matter how reliable the parties involved. While you might expect that past experiences or trauma can affect your ability or willingness to trust, a new study suggests that negative emotions make it harder to trust others — even if they're completely unrelated to the person or situation at hand. According to scientists at the University of Zurich and the University of Amsterdam, these "incidental emotions" can "significantly suppress" our ability to trust another person.

The team behind the study, published in the journal Science Advances, looked into whether "incidental aversive affect can influence trust behaviour and the brain networks relevant for supporting social cognition" — essentially, whether an unrelated negative emotion can compromise our capacity for trust. That unrelated emotion could be as simple as frustration over a parking fine, the researchers suggested.

To do so, they asked 41 participants to play a trust game, asking them to decide how much money to invest in a stranger who might either repay them, or keep the money for themselves. The participants were told they might receive an "unpleasant electrical shock" as they were playing, resulting in a state of "anticipatory anxiety."

Chelsea Victoria/Stocksy

When the participants feared they might receive a shock, they were significantly less likely to demonstrate trust by investing while playing the game — even though the threat of the shock was completely unrelated to their actions in the game. What's more, MRI scans of their brains revealed that a region of the brain essential to "understanding others' beliefs," the temporoparietal junction, was suppressed when they played the game while feeling anxious, as was the connection between the temporoparietal junction and the amygdala, an area of the brain central to processing emotions.

Anxiety also affected other areas of the brain, the researchers found. They explained in a press release that "under safe conditions, the strength of the connectivity between the TPJ and other important social cognition regions, such as the posterior superior temporal sulcus and the dorsomedial prefrontal cortex, predicted how much participants trusted others."

When the participants felt anxious, however, the link between brain activity and trusting behaviour was severed. In less scientific terms? Negative emotions like anxiety alter the activity of our brains, and make it harder for us to understand other people.

GIC/Stocksy

Study authors Jan Engelmann and Christian Ruff said in a press release, "These results show that negative emotions can significantly impact our social interactions, and specifically how much we trust others." They added that the findings "reveal the underlying effects of negative affect on brain circuitry: Negative affect suppresses the social cognitive neural machinery important for understanding and predicting others' behaviour."

Engelmann also posited that the findings could have major social implications. "Negative emotions, even if they are incidental, may distort how we make important social decisions, including voting," he said. Figuring out who and when to trust was never a simple matter, but if the findings of this latest study hold true, it might be an awful lot more complicated than first thought.