Basically, your brain gets used to it. Yikes.

It's easy to spot a habitual liar once you get to know them, and everyone's encountered that person who lies about absolutely everything, even things that don't make any sense. It's totally infuriating! Maybe they embellish on their past achievements, say they went somewhere when you know they didn't, or just tell a few too many really impressive stories. Well, recent research may explain why people have a hard time getting out of the habit of lying once they start. (BTW, here's how the stress of lying affects your health.)

A new study published in Nature Neuroscience showed that the more you lie, the more your brain gets used to it. Basically, the researchers found a way to scientifically prove what many already believe to be true: lying gets easier with practice. In order to measure this, the scientists enlisted 80 volunteers and had them tell lies while taking functional MRI scans of their brains. People were shown an image of a jar of pennies and asked to guess how many pennies were in the jar. They then had to advise their "partner," who was actually part of the research team, on their estimate, and their partner would then make the final guess as to how many pennies the jar contained. This task was completed in several different scenarios where it benefited the participant to lie about their estimation for their own self-interest as well as their partner's interest. What the researchers observed was pretty much what they expected, but still a bit unsettling. In the beginning, telling lies for reasons based in self-interest increased activity the amygdala, the brain's main emotional center. As people continued to tell lies, though, that activity decreased.

"When we lie for personal gain, our amygdala produces a negative feeling that limits the extent to which we are prepared to lie," as Tali Sharot, Ph.D., senior study author, explained in a press release. Which is why lying does not feel good if you're not accustomed to it. "However, this response fades as we continue to lie, and the more it falls the bigger our lies become," says Sharot. "This may lead to a 'slippery slope' where small acts of dishonesty escalate into more significant lies." The researchers further theorized that this decrease in brain activity was due to a lessened emotional response to the act of lying, but more studies need to be done in order to confirm this idea.

So what can we glean from this study as is? Well, it's clear that practiced liars are better, and the more you lie, the better your brain gets at compensating for it internally. Based on what we know now, it might be a good idea to remind yourself the next time you're considering telling a white lie that the practice can be habit-forming.