Empathy,a basic social cognitive function,plays a vital role in everyones daily life.Two kinds of stimulus materials(painful facial expressions and body parts receiving painful stimulation)are widely used as representations of others pain in these research.However,what is always ignored by previous studies is that the two kinds of stimuli may result in different psychological processes of the observers,e.g.,one may imagine he himself in pain when viewing injured body parts while do not implicate himself when seeing painful faces.The present study focused on the differences between empathic responses elicited by painful expressions and needle-pricked body parts.Highly ecological validity video clips were prerecorded depicting people being injected(n=10,4 males).The videos were split and trimmed into two different clips,consisting of faces and injected arms respectively.The control video clips were recorded from additional 10 subjects showing neutral expressions with arms being wiped by a Q-tip.A total of 28 video clips are assigned to 3 blocks.Thirty-six graduate and undergraduate subjects(males 12,age 22.0±1.8)participated in this experiment.Facial electromyography(EMG)and pulse rate were recorded to assess the emotional responses elicited by visual stimuli.Subjective ratings of pain intensity and unpleasantness as well as IRI were measured after the termination of video stimuli.The results showed that,compared to the neutral videos,viewing pain videos elicited more corrugator activity,lower pulse rate,and higher pain ratings.Further more,stronger empathetic reactions(more corrugator activity,lower pulse rate,and higher pain ratings were also found when watching arm-pain videos than face-pain ones.These results suggest that observing injured body may lead to more self involvement relative to observing painful faces.Using the event-related potential approach,we examined the differences between brain responses elicited by visual images of painful faces versus needle-pricked arm.The time-course of empathic reactions to painful condition and nonpainful condition was investigated and compared.The preliminary data showed face-locked ERP components(N1,P2 and N2)recorded at electrode site Cz.The arm-locked ERPs displayed longer latency and lower amplitude as compared to the face-locked ERPs.Painful faces elicited N1 and P2 of greater amplitude than neutral faces.Further analysis of electrophysiological data is being done relating to the late,emotion-related components as well.