Ever felt panic at the thought of losing your phone? A new study suggests that smartphone separation affects performance. “We experience a lessening of self and a damaging physiological state,” says the study’s lead author, Russell Clayton. He had 40 study participants solve a puzzle — once while holding their iPhones and once without them. The phone-less suffered increased blood pressure, heart rate and anxiety. So do we need to wean ourselves from our phones? Nah, it might do more harm than good.