The costs of lying extend beyond burning pants. According to new research led by Anita Kelly, a psychologist at the University of Notre Dame who studies secrecy, self-disclosure, and self-presentation, telling lies—both little "white lies" and major deceptions—takes a psychological and physiological toll.
Kelly and her collaborators spent 10 weeks with 110 subjects of various ages and backgrounds. Half of the subjects were told to stop telling lies, both big and small, for the duration of the study. The other half was given no special instructions. Every week, both groups would come in for tests that assessed how frequently they had lied in the past week and measured their well-being.
The result? Those who lied less reported not only better mental health (feeling less tense, for example), but also fewer physical ailments like headaches. From Notre Dame:
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.
Interestingly, the benefits of lying less were greater for people in the group who were asked not to lie at the outset. That's probably because their lying less was the product of a deliberate effort, rather than just random variation.
So why does lying less have these benefits? Kelly says that, in trying to lie less, participants "realized they could simply tell the truth about their daily accomplishments rather than exaggerate... [or stop] making false excuses for being late or failing to complete tasks." My guess is that in trying not to lie to others, these people also got more honest with themselves. And that's just a prerequisite for clear-eyed living.