How White Lies Snowball Into Full-On Deception

Using brain scans, researchers find evidence that bad feelings associated with lying lessen over time

Why do some people seem able to lie without feeling bad? caracterdesign / iStock

You walk into a room and are overwhelmed by the stench of sour milk, stinky feet, or whatever it is that makes your nose scrunch. But force yourself to stay in that room long enough, and that bad smell—along with those negative feelings associated with it—diminish or sometimes even disappear. It’s the same phenomenon that explains how you survived freshman year with that roommate who never showered: You acclimated.

Now, new research suggests that the concept of how we adapt to unpleasant physical sensations extends to our psyches as well. In a somewhat unnerving finding, it seems that repeatedly telling lies can similarly dull our senses, diminishing negative feelings associated with lying and making it emotionally easier to tell larger, subsequent lies. The study, published this week in the journal Nature Neuroscience, offers a fascinating look at how a person can come to tell whopping lies with little emotional discomfort.

“Anecdotally it has been suggested that there is this slippery slope and dishonesty grows and grows,” says study author Tali Sharot, an experimental psychologist at the University College London. “But there wasn’t any empirical research showing why that may happen and the biological processes that may be supporting it.”

To study how lying may become less emotionally taxing over time, the researchers created a game that incentivized participants to lie in return for a cash prize. More than 80 participants were challenged to estimate the amount of coins they saw in a picture of a jar full of coins, and were then told to help another participant—called the estimator—estimate how many coins were in the jar. The advisors didn’t know that the estimators were actually just actors involved in the study.

The researchers posed about 60 different scenarios per group that would either incentivize the participants to overestimate, underestimate, or properly estimate the coins in the jar. Sometimes lying helped the estimator win the cash prize; sometimes it helped the advisor win.

Researchers focused on the amygdala, the almond-shaped region of the brain that is associated with fear, anxiety and other emotions, and is known to show increased activity when someone's emotions are triggered. When researchers studied the brain activity of a portion of the participants using an MRI machine, they found that the amygdala became less aroused with each subsequent lie that an advisor told for their own benefit, suggesting that the negative feelings that go along with telling lies dulled over time.

How White Lies Snowball Into Full-On Deception
Brain scans showing reduction in sensitivity to dishonesty over time. The lighter colors show emotional response to dishonesty. Neil Garrett, Stephanie Lazzao, Dan Ariely, Tali Sharot, Nature Neuroscience

Previous studies have demonstrated that dishonesty escalates when a reward for lying grows or somehow changes in a person’s mind, such as when they think they might be about to miss out on a good opportunity. But this was the first time researchers have shown dishonesty escalating with no changing motivator, says lead author Neil Garrett, a postdoctoral researcher in neuroscience at Princeton University.

“It’s the first time in a laboratory setting people have shown dishonesty escalation when you don’t change anything else,” says Garrett.

The team suggests that policy makers could draw on their findings to reduce dishonesty and deceit in society, though Garrett says it’s unclear exactly how this would work. One possibility Sharot suggests is that arousing a person’s emotional state during the time of lying—even if the arousal has nothing to do with the content of the lie—may help counteract the dulling effect. In other words, make people more emotional at the same time that they have an opportunity to be dishonest—the same idea behind “No Shoplifting” signs in fitting rooms.

For example, it’s possible that placing an image or sign that elicits negative feelings in a classroom during a test could decrease the likelihood of cheating, Sharot says. “Perhaps the arousal will be misattributed and students will think that they are aroused because they are about to cheat, and that will make them less likely to cheat,” says Sharot, adding that this is just speculation and has not been tested.

It's still uncertain whether the phenomenon the researchers found is truly due to decreased negative feelings or whether it is actually due to a mix of dulling both positive and negative emotions, Garrett says. Previous research has suggested that lying elicits bad feelings, but looking at the MRI from their study alone does not offer this conclusive information, he adds.

Other researchers in the field agree that this new study is compelling, but say more work will be needed to better understand the emotional complexity of lying and how it appears in the brain. “While it’s important to realize that brain regions are highly interconnected networks, it’s very interesting to see this evidence that amygdala activity tracks self-serving dishonesty,” says Bryan Denny, a psychology professor at Rice University who has studied the effect of emotions on the amygdala and was not involved in this study.

Luke Chang, a psychology researcher at Dartmouth College who studies how emotions are represented in the brain, also finds the study provocative but says more work is needed to tease out the emotional response in the amygdala. “If it’s true that they feel less bad each time, that’s interesting,” he says. “But I would want to see converging evidence that that’s the case." Such additional evidence could include measurements of skin conductance or heart rate during lying, which are also indicative of emotional states, Chang adds.

Still, finding links between behavior and brain scans is generally a challenging task. The study's authors roffer a compelling case for how people make decisions and how our emotional reactions to dishonesty change over time—which could ultimately help us understand the motivations behind malicious acts, says Chang.

Or, help us become better liars.

Get the latest Science stories in your inbox.