Pain isn't always a pain. Sometimes it can actually feel good.
People experience pleasure during a painful stimulus if the stimulus turns out to be less bad than they were expecting, new research suggests.
"It is not hard to understand that pain can be interpreted as less severe when an individual is aware that it could have been much more painful," said study co-author Siri Leknes, a psychologist at the University of Oslo in Norway, in a statement. "Less expected, however, is the discovery that pain may be experienced as pleasant if something worse has been avoided."
The findings were published in the March issue of the journal Pain.
To see how people perceived pain, Leknes and her colleagues hooked 16 participants up to a device that applied a variable level of painful heat to their arms. At the same time, the researchers measured their brain activity using magnetic resonance imaging (MRI) scans.
In the first setting, participants experienced a series of either a slightly painful stimulus — about as painful as grasping a slightly too hot cup of coffee — or no pain.
In a second setup, the participants experienced a series of either moderate or intense pain. On a screen, the participants could see what type of pain was coming up next in the series.
In the first scenario, the participants rated the moderate pain as unpleasant.
What a relief
But interestingly, participants rated the moderate pain as actually pleasurable in the second setup, when the alternative was the intense pain. During the moderate stimulus in the second setup, participants' brain activity also showed less activation in the pain region of the brain (the brain stem) and more activation in a region in the middle of the frontal lobes that's associated with pain relief and pleasure than during the same stimulus in the first setup. ...