Abstract: Overlapping neural circuits labeled as the "pain matrix" have been implicated in brain responses to both subjective pain perception and response to others' pain. However, evidence suggests brain structures with a spatial con?guration similar to that of the "pain matrix" are also activated by non-nociceptive stimuli, thus questioning the specificity of pain matrix activation to noxious stimulation. This research assessed the extent to behavioral responses to subjective pain perception and the detection of pain in others were congruent with each other compared to non-noxious alternatives. In Experiment 1, pain and heat stimuli previously primed with painful or non-painful pictures were applied to an undergraduate sample. Participants (15 men and 15 women) were instructed to respond to the pain or heat stimuli, judging as quickly and accurately as possible whether stimuli were painful or not painful, and rating pain intensities and unpleasantness of stimuli. Shorter reaction times as well as higher pain intensity and unpleasantness ratings were found in response to pain stimulation following painful priming pictures than non-painful pictures. However, responses to heat stimuli were not influenced by painful and non-painful primes. In Experiment 2, the same participants completed an identical task with the exception that either painful or heat stimulation was used to prime responses to painful and non-painful depictions. Once again, shorter reaction times were found in response to painful pictures following pain stimuli than heat stimuli yet responses to non-painful pictures were not influenced by pain and heat stimuli. Together, findings suggested that the processing of pain representations leads to congruent behavioral responses to subjectively experienced pain and pain in others.

Key words: pain, empathy for pain, congruency effect