“Pants on fire” isn’t the only problem liars face. New research from the University of Notre Dame shows that when people managed to reduce their lies in given weeks across a 10-week study, they reported significantly improved physical and mental health in those same weeks.

Funded by a grant from the John Templeton Foundation, the “Science of Honesty” study was presented recently at the American Psychological Association’s 120th annual convention.

“We found that the participants could purposefully and dramatically reduce their everyday lies, and that in turn was associated with significantly improved health,” says lead author Anita Kelly, a Notre Dame psychology professor whose research includes the study of secrets and self-disclosure.

Kelly and co-author Lijuan Wang, also of Notre Dame, conducted the honesty experiment over 10 weeks with a sample of 110 people, 35 percent of whom were adults and 65 percent of whom were college students. They ranged in age from 18 to 71 years, with an average age of 31.

Anita Kelly

Approximately half the participants were instructed to stop telling both major and minor lies for the duration of the 10-week study. The other half served as a control group that received no special instructions about lying. Both groups came to the laboratory weekly to complete health and relationship measures and to take a polygraph test assessing the number of major and white lies they had told during that week. According to Kelly, Americans average about 11 lies per week.

Over the course of 10 weeks, the link between less lying and better health was significantly stronger for participants in the no-lie group, the study found. For example, when participants in the no-lie group told three fewer white lies than they did in other weeks, they experienced on average about four fewer mental-health complaints, such as feeling tense or melancholy, and about three fewer physical complaints, such as sore throats and headaches, the researchers found.

In contrast, when control group members told three fewer white lies, they experienced two fewer mental-health complaints and about one less physical complaint. The pattern was similar for major lies, Kelly said.

Compared to the control group, participants in the more truthful group told significantly fewer lies across the 10-week study, and by the fifth week, they saw themselves as more honest, Kelly said. When participants across both groups lied less in a given week, they reported their physical health and mental health to be significantly better that week.

The study also revealed positive results in participants’ personal relationships, with those in the no-lie group reporting improved relationship and social interactions overall going more smoothly when they told no lies.

“Statistical analyses showed that this improvement in relationships significantly accounted for the improvement in health that was associated with less lying,” said Wang, who is a statistician.

Is it difficult to keep from lying in day-to-day interaction?

Participants said they realized they could simply tell the truth about their daily accomplishments rather than exaggerate, while others said they stopped making false excuses for being late or failing to complete tasks, Kelly said. Others said they learned to avoid lying by responding to a troubling question with another question to distract the person, she said.

Contact: Anita Kelly, akelly@nd.edu