Reach for the hand of a loved one in pain and not only will your breathing and heart rate synchronize with theirs, your brain wave patterns will couple up too, according to a new study. The study, by researchers with CU Boulder and University of Haifa, in collaboration with the Institut Pasteur published in the journal Proceedings of the National Academy of Sciences (PNAS) this week, also found that the more empathy a comforting partner feels for a partner in pain, the more their brainwaves fall into sync.