There are plenty of contradictory and uncertain findings in psychology. The benefits of nature are not among them. Study after study after study agrees that spending time in nature makes us happier, less stressed, physically healthier, and even slows down the aging of the brain

Yet even as the case for time in nature grows stronger, academic anxiety, social trends, and changes to how we build our neighborhoods are conspiring to keep kids indoors more and more. That's not good for their happiness (or the future health of the planet) new research suggests. 

Outdoor kids are happier kids. 

Just a few decades ago, kids would get pushed out the door by their parents after school and told not to come home until hours later. These days, in many places, someone would probably call the police on a parent who did that. How are all those additional hours staring at screens and participating in indoor activities affecting our children? A team of Mexican researchers decided to find out. 

To assess the impact of time in nature on kids' psychology they surveyed nearly 300 children aged nine to twelve from a Mexican city about how much time they spent outside, their pro-environmental actions, and their levels of happiness. The relationship between outdoor play, action to take care of the planet, and personal well-being was clear. 

"The researchers found that in children, feeling connected to nature had positive associations for sustainability practices and behaviors, and also led to children reporting higher levels of perceived happiness," reports Neuroscience News

That's not just because 'nature deficit disorder' is bad for the mental health of humans no matter their age. The researchers believe spending time in the great outdoors has subtler benefits for kids as well. 

"Connectedness to nature is not just appreciating nature's beauty, but also being aware of the interrelation and dependence between ourselves and nature, appreciating all of the nuances of nature, and feeling a part of it," said Laura Berrera-Hernández, one of the researchers behind the study. 

Time in nature isn't just about exercise, mental health, and fostering a sense of responsibility for the planet, though those are all benefits. It's also about showing kids the grandeur and interdependence of life on earth. That should lead to more recycling, sure, but also more awe and a joyful sense of belonging. 

In short, spending time in nature is good for children's spirits. So why not hit the park or local hiking trail this weekend?