We've all told the occasional white lie: We fake sick to get out of a pity date; pass takeout as our culinary creation; or lie on our resume to get the job. Although some fibs are smaller than others, constantly lying can take a toll on our brain health, and even make us more susceptible to pathological lying. A recent study in Nature Neuroscience found habitual lying can desensitize our brains from “feeling bad,” and may even encourage us to tell bigger lies in the future.

"When we lie for personal gain, our amygdala produces a negative feeling that limits the extent to which we are prepared to lie," said Dr. Tali Sharot, senior author of the study, director of the Affective Brain Lab at the University College of London and a faculty member of the department of Experimental Psychology, in a statement.

However, as we continue to lie, this response fades, which may lead to a “slippery slope” where small acts of dishonesty can evolve into more significant lies. In other words, lies breed lies as the brain gets desensitized to dishonesty.

This is particularly troubling since the average American tells one to two lies a day. Those who tend to be insecure or have an anxious or avoidant attachment style are more likely to be dishonest to avoid being criticized, rejected, or left with less than someone else has, according to a 2010 study. Also, those who believe lying will give them monetary or social recognition are more likely to continue being dishonest.

Sharot and her team of researchers know when we deceive someone, the amygdala, the part of the brain that regulates emotion, is activated, and we tend to feel shame or guilt. This part of the brain also reacts when we see cute pictures of puppies or very sad photos. The amygdala becomes more desensitized when it’s continually exposed to these same photos. The researchers wanted to know if the same could apply to lying.

The team recruited participants and paired them to work with another person they didn't know. The participants were put into a brain-imaging scanner where they were shown images of a glass jar with pennies and asked to tell their partners — who had a blurry image, and were helping the researchers — about the amount of money in the jar. At the end, both participants would get paid, but sometime the participants would get more money if they lied. For example, they could lie to help themselves, help their partners, help both etc.

The brain scans would help researchers see which brain regions used more oxygen — an indicator of brain activity. A following pattern emerged: as the participants continued to lie, the amygdala reacted less. The participants became more dishonest more quickly when it would benefit just them and not their partner. The participants kept lying to help themselves even if lying didn’t lead to more money every single time.

This suggests people kept lying not because it seemed sensible, but because they've become desensitized to it.

"It is likely the brain's blunted response to repeated acts of dishonesty reflects a reduced emotional response to these acts," said Dr, Neil Garrett, lead author of the study.

This behavior could breed a pathological liar, which is someone who lies out of habit without any reason.

The findings warrant further investigation since it was conducted in a lab, and not a real-world setting. The researchers didn’t give the participants consequences for lying. They also controlled who the participants were paired up with and how the structure of the game worked. This isn’t the case when lying in our daily lives.

Bottom line: The occasional white lie here and there is OK, as long as you don't make a habit of it.

Source: Garrett N, Lazzaro SC, Ariely D et al. The brain adapts to dishonesty. Nature Neuroscience. 2016.