Mindfulness meditation is incredibly popular right now.

According to the National Institute of Health, 18 million people in the US have meditated, or 8% of the population.

Studies suggests that the practice lessens stresses, increases memory, and may even help prevent genetic damage related to cancer.

While there is an ever-increasing amount of academic research around the practice and its effects, scientists are still figuring out what precisely is happening when people meditate, and what effects that behavior has on the brain.

Harvard neuroscientist Sara Lazar, a leading researcher in the field, is one of the first to show that meditation practice produces structural changes in the brain.

In 2005, her team was the first to show how long-term meditation practice correlates with cortical thickening in brain areas associated with attention, sensory processing, and interoception (the awareness someone has about the physiological state of their body).

In a 2011 paper, she found that people who learned meditation for the first time in an eight-week course had increases in gray matter concentration in areas of the brain associated with "learning and memory processes, emotion regulation, self-referential processing, and perspective taking."

The research suggests that "changes in brain structure may underlie some of these reported improvements and that people are not just feeling better because they are spending time relaxing," Lazar says.

Those changes to brain structure come with big changes in mental activity.

Lazar revealed a few of them to Tech Insider:

• Understanding yourself (and other people too). Meditation increases your awareness of "minimally conscious thoughts and emotions," or quieter emotions that otherwise go unnoticed. "You have probably experienced many emotions that you're not even aware of," Lazar says. "If you understand them in yourself, you'll understand them better in other people."

• Emotional strength. When you have a higher resolution image of your emotional landscape, then you're less to be swayed by each individual feeling. "If you have a better handle of all the different emotions, you realize, 'Ok, this emotion isn't useful,'" Lazar says. "It gives you more information, and information is power."

• Getting less freaked out by stress. "You're less likely to make a rash decision," Lazar says. "You're less stressed, you're less caught up in the hullabaloo around you. I think that's important regardless of what you do. it plays into quality of life. I still get stressed, but it takes more to make me stressed out."

Lazar is careful to note that your brain changes when you learn anything, be it a second language or juggling. Same with meditation: though it can be an intimidatingly abstract activity when you first encounter it, mindfulness meditation is an exercise that you can learn to get better at, just like swinging at a baseball.

It works like this.

"You pick one object," Lazar says. "For many people, it's breathing sensations. It doesn't have to be that, but it's the most common thing to start with. You notice that, and your mind is going to get bored, and it's going to start wandering, and then you realize, oh, my mind is starting to wander, and bring it back to breath."

Instead of manipulating a bat to hit a ball, Lazar says that you're using two of the mind's go-to instruments: attention and metacognition, or your awareness of your own thoughts.

"Attention helps you stay focused, and metacognition helps you to see all the minimally conscious content," Lazar says. "You think, this is boring, but what else is happening? You start to notice little thoughts and feeling happening in the back. They're happening all the time, and we miss them 80% or 90% of the time. You notice there's a lot more going on that you never saw before."

Lazar has had a personal practice for nearly two decades, but she fell into meditation unexpectedly. When she and a friend over-trained for the Boston Marathon and ended up hurting themselves, Lazar started going to yoga to help recover.

Then she got into mindfulness meditation. "It was really clear that something in my brain had changed," she tells Tech Insider. "I was noticing things I hadn't noticed before, and I was less reactive to things that would piss me off."

Lazar is careful to note that meditation is not a cure-all, in the same way that while exercise is a terrifically excellent thing to do for yourself, it's not the only thing you should be doing for your overall well-being.

"It's not you start meditation and you become a Buddhist monk," Lazar says. "It will help promote attention and metacognition. The benefits are real and beneficial, but it's not like you become a super person because of this."

Watch Lazar's 2011 TedX talk on meditation's effects on the brain below.