I read a study once, where it was determined that physical pain can be lessened simply by the presence of another person, even if the subject is not interacting with the person.  In the study, the subject sat alone in a room with his feet in ice water.  He would signal the researchers when the pain became too much to bear and he was ready to stop.   The amount of time the subject was able to go without unbearable pain more than doubled with the introduction of another person at the far end of the same room.  They did not speak nor make eye contact.  Simply the presence of the other person was enough to make it possible for the subject to bear their pain for almost twice as long.