Pain Hurts More If [you think that the] Person Hurting You Means It

"Researchers at Harvard University have discovered that our experience of pain depends on whether we think someone caused the pain intentionally. In their study, participants who believed they were getting an electrical shock from another person on purpose, rather than accidentally, rated the very same shock as more painful. Participants seemed to get used to shocks that were delivered unintentionally, but those given on purpose had a fresh sting every time."


http://www.sciencedaily.com/releases/2008/12/081215111307.htm