If your brain feels like it's being pulled in a million directions, it's time to go outside — so says journalist Florence Williams, the author of a recent piece for National Geographic called "This Is Your Brain On Nature."

"A little bit of nature really helps improve our mood, might make us have less negative thoughts and might sort of perk us up," said Williams.

Modern life can be stressful and fast-paced, and according to University of Utah cognitive psychologist David Strayer — one of the subjects in Williams' piece — it can take a toll on our brains.

"We're constantly switching attention from one thing to another," he said. "The cellphone is kind of a medium that basically just pulls attention left, right and center. And that's, in the long run, not overly healthy for us. It tends to degrade the quality of our thinking. It tends to stress us out."

That's where going outside comes in — and the longer the trip, the better. Williams said she's observed a "dose effect" when it comes to time spent outside: "The more time we spend in nature, more profound things seem to happen."

Strayer said he's observed the dose effect too, and that science backs up that idea.

"People say that after two or three days, they start to really think differently," he said. "They tend to notice things, sounds, smells, different things. You're more connected with the physical environment."

Williams said that during these longer trips, it's not uncommon for people to start pondering the larger questions they often don't think about during the daily grind — their hopes and dreams, and the challenges they're facing.

There are additional benefits as well, said Strayer, including one unexpected perk: research has shown that a few days in nature can spark a "burst in creativity."

While Strayer encourages people to get out and spend days in nature, he knows it's a luxury that not everyone can take advantage of. That said, he said that even a short walk in a natural setting, like a park or an arboretum, can reap benefits.

"The studies have shown that 20 to 30 minutes in that kind of environment, when you leave your phone aside, will really lead to kind of a lot of improvements in thinking," he said.

And leaving the phone aside is something Strayer can't stress enough: "Our research shows that if you are in that same environment, but you're holding a phone and talking, that you negate most of the benefits," he said.

And even though it's winter, which here in Wisconsin means snow and blustery temperatures, Strayer said it's still restorative to go outside. For those who want to take Strayer up on the recommendation, here's a map of state parks to check out.