The whole point of carrying around a powerful computer in your pocket is that it helps you connect with other people. Forgot to include an important detail in that work report? Just open your email. Running late? Text your spouse a heads up. Need to let your local Chinese place know you're starving? There's an app for that.

That's the theory anyway. But as anyone who has been frustrated by a gathering where everyone is constantly on their phones can tell you, the reality is often far different. We've all experienced how screens can alienate us from each other. A new study explains exactly how they push us toward loneliness -- and it makes for some pretty grim reading.

Your phone is a smile-eating machine.

The new research out of the University of Virginia is hardly the first study to delve into the effects of phone use on our social lives. Plenty of previous work has found your phone is terrible for your relationships too. One study showed romantic partners are jealous of the attention their other half's phone time, worsening the quality of the relationship. Another showed that simply having a phone visible nudged people away from real conversation and toward less satisfying small talk.

These results sound bad, but the latest findings are perhaps even more depressing -- it turns out your phone is quite literally stealing your smiles.

To reach this conclusion scientists videotaped and carefully analyzed pairs of volunteers who believed they were waiting for a researcher who was running late. Some were allowed to bring their phones into the waiting room. Other were instructed to leave them outside. You probably won't be shocked to hear those with phones interacted less with the other human being sharing a small room with them. But more surprisingly, they also smiled less -- a lot less.

"People with phones exhibited fewer smiles overall (and fewer genuine smiles), and spent 30 percent less of the time smiling than people who didn't have their phones with them, signaling less interest in connecting with others," writes Jill Suttie in her writeup of the research for UC Berkeley's Greater Good Science Center.

Fewer smiles means less human connection.

A lack of smiling isn't just a decent sign that scrolling through envy-inducing social-media feeds and reading the latest crop of miserable headlines doesn't do much for our happiness. It's also catastrophic for social connection, Suttie explains, because the smile is the oil that lubricates most human interaction.

"Besides indicating happiness, a smile also communicates to others that you're interested in them and trustworthy. So if phones make us smile less when we're out and about in public, it could thwart our ability to form 'weak ties'--connections with neighbors, colleagues, and other non-intimates in our community--that have been shown to have a profound effect on our health and happiness," she writes.

So not only is your grim phone face an indication of its true effect on your mood, it's also warning off others who might actually want to interact with you and bring joy into your day.

The lesson here isn't hard to divine. Phones have their uses, but if you're constantly staring at yours in public, you're probably robbing yourself of both smiles and human interaction. It might seems scary, dull, or downright old fashioned, but next time you're in a waiting room, why not skip reaching for your phone and actually talk to someone instead?