Could our hormones influence whether we vote?

Past research has associated high levels of cortisol - known as the "stress hormone" - with increased risk of heart attack and memory loss. But now, a new study has found a surprising link with the hormone; it could influence our voting behavior.

The study team, including researchers from the University of Nebraska at Omaha (UNO), the University of Nebraska-Lincoln (UNL) and Rice University in Texas, recently published their findings in the journal Physiology & Behavior.

According to the investigators, there is growing evidence that biological predisposition may affect an individual's voting behavior. 

In 2012, researchers reported on a study suggesting that people are more likely to vote for political candidates with deeper voices.

In this study, the team set out to determine if cortisol levels affect whether a person will vote in general or national elections. Cortisol is a glucocorticoid hormone that is produced by adrenal glands at the top of each kidney in response to stress.

It's long been known that cortisol levels are associated with your willingness to interact socially - that's something fairly well established in the research literature. The big contribution here is that nobody really looked at politics and voting behaviors before.

High afternoon cortisol levels linked to lower voting participation

To reach their findings, the investigators collected saliva samples of 105 participants who described themselves as disinterested in politics, highly conservative or highly liberal.

Saliva was collected from the participants before and during afternoon activities that increased or reduced stress. The team then measured the levels of cortisol in the samples, before analyzing participants' self-reported voting behaviors over six national elections.

The team found that participants who had low afternoon cortisol levels were more likely to vote in national elections, while those with high afternoon cortisol levels were less likely to vote.

The team found that activities that induced high levels of stress increased cortisol production. 

But more notably, they found that participants who had low afternoon cortisol levels prior to taking part in the activities were more likely to vote in national elections, while those with high afternoon cortisol levels were less likely to vote.

Participation in another group-oriented activity, specifically religious participation, was not as strongly associated with cortisol levels.

Involvement in nonvoting political activities, such as volunteering for a campaign, financial political contributions, or correspondence with elected officials, was not predicted by levels of stress hormones.

The researchers say that participation in US national elections is low - at between 40-60% - and that their findings may explain why.

Politics and political participation is an inherently stressful activity. It would logically follow that those individuals with low thresholds for stress might avoid engaging in that activity, and our study confirmed that hypothesis.

The research team notes that past research has associated high afternoon cortisol levels with social withdrawal, major depressive disorder, separation anxiety and enhanced memory for fearful stimuli, which may explain the team's findings.

High afternoon cortisol is reflective of a variety of social, cognitive and emotional processes, and may also influence a trait as complex as voting behavior.

"The key takeaway from this research, I believe, is that while social scientists have spent decades trying to predict voting behavior based on demographic information, there is much to be learned from looking at biological differences as well.

Many factors influence the decision to participate in the most important political activity in our democracy, and our study demonstrates that stress physiology is an important biological factor in this decision. Our experiment helps to more fully explain why some people engage in electoral politics and others do not."

Researchers recently reported on a study suggesting stress can reduce sperm and semen quality, which may have implications for male fertility.