In a first of its kind study, scientists from the Swiss Federal Institute of Technology at Lausanne University have found a link between stress and social inequality.

Previous studies have associated the effects of stress with the release of the hormone cortisol. But based on the present study’s participant behavior, stress impacts our level of confidence. And confidence, according to researchers, is what drives social competition; without it, we don’t make decisions that give us an edge over components, thus influencing the way individuals interact with one another. So if we’re more stressed than confident, are we fueling inequality?

Scientists recruited over 200 people to find out. Each participant took two online tests designed to assess IQ and measure trait anxiety. Trait anxiety refers to general anxiety, the type of anxiety in a person’s personality, not a result of fear or certain situation. Participants were invited back a week later to undergo a psychological procedure designed to cause acute stress, such as mock interviews and mental math tests.

Only half of the participants underwent the procedure, and the remainder participants were not subjected to stress in order to serve as a control. Then all participants came back together to answer a scenario in which they could win money: The first option was to take their chances and play a lottery, while the second was to use their IQ score to compete with another participant for the prize in which the participant with the higher IQ would win.

The results showed nearly 60 percent of non-stressed participants chose the IQ score over the lottery, regardless of their trait anxiety. The stressed participants, however, varied depending on their trait anxiety scores. Acute stress increased competitive confidence if participants had low level anxiety, whereas confidence dropped in participants who were highly anxious. This suggests stress can raise or suppress competition depending on their predisposition to anxiety.

And similar to studies before it, researchers found the effects of stress are mediated by cortisol. Participants with low and high anxiety scores showed a higher response to cortisol, “which connects the behavioral effects of stress to a biological mechanism.”

"People often interpret self-confidence as competence," Carmen Sandi, study author, said in a press release. "So if the stress of, say, a job interview, makes a person over-confident, they will be more likely to be hired — even though they might not be more competent than other candidates. This would be the case for people with low anxiety."

Given this evidence stress can ultimately impact social equality, it can then serve as an obstacle toward overcoming socioeconomic inequality by trapping the more anxious people “in a self-perpetuating loop of low competitive confidence.”

Sandi and her team said they’d like to expand upon this research and use brain imaging to see if we can change the way we look at social dynamics as a whole.

Source: Goette L, Bendahan S, Thoresen J, Hollis F, Sandi C. Stress pulls us apart: Anxiety leads to differences in competitive confidence under stress. Psychoneuroendocrinology. 2015.