We all have a friend or family member who never seems to be able to put their smartphone down. Not to be a curmudgeon, but it’s annoying, and sometimes downright rude—you go out to a restaurant with friends, and as soon as you sit down, they’re checking in, posting updates, and taking pictures of their food. They’re ignoring the people who are there for those who aren’t, so before long, you introduce the phone stack policy for social gatherings.

Now comes evidence, though, that this connection with our phones is more than just a joke. Researchers from the University of Missouri conducted a study “to examine the degree to which perceived level of self, cognition, emotion, and physiology are affected when a participant is separated from their iPhone while it is ringing.”

Keep Your Friends Close and Your Phones Closer
The experiment tested iPhone users’ blood pressure, heart rate, and cognitive performance during a controlled test, and then again when moving the subjects’ phones across the room and calling them. While the study specifically mentions iPhones, and the vast majority of subjects had them, some did have other types of smartphones. Cognitive performance was measured by having the subjects perform word puzzles.

Results from the experiment showed that phone separation caused negative physical, mental, and psychological effects. Subjects’ heart rates and blood pressure went up, and cognitive performance went down when users were unable to answer their ringing phones. These subjects also reported unpleasantness and anxiety during those times. Researchers concluded “iPhone users indeed felt greater extension of self when in possession of their iPhone as opposed to during separation.”

Our Phones Become Part of Our Identity
When we can’t access our smartphones, we feel as if there’s a part of us missing. Forget Snickers and hunger: you’re not you when you can’t answer your phone. So when we create those phone stacks thinking we’re helping, temporarily freeing us from the stress of being connected to our phones, we’re actually doing the opposite.

Study Limitations
The researchers behind the study admit that its sample size of 136 subjects is small, and recommends additional study of this topic. Also, while the experiment didn’t test for response to text or email notifications, we’re willing to bet they would have produced the same reaction, if not a more severe one, than a call. But science is about actually confirming hypotheses, not just making a good guess.

Are We Really Addicted to Our Phones?
Another study indicates that what we’re addicted to isn’t the phone itself, but the habit of checking it for updates. The average user checks his phone 35 times a day and, according to the director of the Center for Internet and Technology Addiction, Dr. David Greenfield, 90 percent of Americans overuse, misuse, or abuse their mobile devices.

“The analogy that I use is right before they go to bed, the last thing they do before they pass out is check their phone and the minute they open their eyes, they check their phone,” he said. “Doesn’t that sound like a smoker?”

What to do About It?
Maybe trying to force our friends and family to take a break from their phones isn’t the way to improve social interactions. Instead of trying to enforce behavior, perhaps all of us should try to lead by example, leaving our phones alone when we’re among company.

How connected are you to your phone? Try timing yourself and see how long you can go without checking it. Do you constantly check it even in company? Or do you feel ignored or get upset when others do?