| Empathy and understanding of action intention are believed to share common neural bases,mirror neuron system(MNS)and theory of mind(TOM).However,few empirical studies explored the relationship between them.Previous studies showed that the two components of empathy,affective empathy and cognitive empathy involve MNS and TOM,respectively.Both intention type(e.g.,private and communicative intentions)and intention level(i.e.,‘how’ and ‘why’)of action understanding involve MNS and TOM.Therefore,this paper investigated the difference between different intention types and levels in brain activity under the induced states of affective and cognitive empathy via event related potential in order to explore the relationship between empathy and understanding of action intention.In experiment 1,negative and positive video clips were presented to induce affective empathy state and then several empathy state words were utilized to assess empathy state.EEG was recorded when pictures depicting diverse action intentions were presented.Under the induced state of affective empathy,three ERP components including N1,P3 and late positive component(LPC)during the understanding of action intention are mainly observed.The intention of communicative action elicited significantly larger amplitudes than the intention of private action in N1 and LPC,but smaller amplitude in P3.The results indicate that the intention of communicative action requires more processes than private action intention in early and late stages and less process in middle stage.It demonstrates a transition in the neural mechanism from MNS to TOM during the understanding of action intention.Additionally,the interaction between intention type and intention level is significant in N1 and P3.Specially,low intention level(i.e.,‘how’)requires more process for both the action intentions.It implies that the aroused affective empathy state consumes the resources of action information process which the understanding of low intention level needs.Consequently,the understanding of low intention level requires more cognitive energy.In experiment 2,visual spatial perspective taking task was presented to induce cognitive empathy state and other procedures were same as those in experiment 1.Under the induced state of cognitive empathy,only a LPC is observed.The intention of communicative action elicited significantly larger amplitudes than the intention of private action,indicating that it requires more process.The intention level ‘why’elicited significantly larger amplitudes than ‘how’.The interaction between intention type and intention level is significant.Specially,‘why’ elicited significantly larger amplitudes than ‘how’ in the intention of communicative action.These results indicate that TOM is dominant in processing the understanding of action intention under cognitive empathy state,which might be due to the depletion of ego cognitive resources.The study draws the following conclusions:(1)Under affective empathy state,there is a transition from MNS to TOM during action intention understanding.Specifically,communicative action intention requires more process than private action intention in N1 and LPC,which is opposite to P3.In terms of the action intention level,low level intention requires more process than high level regardless of the action type,for emotion arouse consumes general action information process.(2)Under cognitive empathy state,TOM plays a leading role in action intention understanding.Specifically,‘why’ requires more process than ‘how’ in communicative action intention understanding.The depletion of ego cognitive resources affective long-term intention instead of short-term intention.(3)The dynamic temporal features of action intention understanding under empathy states provides new evidence for the model of transition from MNS to TOM. |
