Inhibitory Effect Of Harm Aversion On Proactive Aggression And Its Brain Association

As a main subtype of aggression,proactive aggression refers to the behavior or tendency to gain personal benefits or achieve personal goals by harming others,including rational thinking,instrumental motivation,moral inhibition and moral disinhibition,which can occur without arousal and emotional calmness,also known as instrumental,premeditated,predatory,deliberate and cold-blooded.They are generally accompanied by plunder,control and bullying.For example,terrorist aggressions,campus bullying,domestic violence,robbery,rumor and other acts that actively hurt others in order to obtain benefits are all proactive aggression.The study of proactive aggression is beneficial to social stability and interpersonal harmony.It is of theoretical value to study the factors that restrain proactive aggression,to reveal the mechanism of proactive aggression,and to apply prevention and intervention of proactive aggression.Harm aversion,as a negative outcome expectation related to aggression on the moral level,is one of the important influencing factors of proactive aggression.Exploring the relationship between injury aversion and proactive aggression is beneficial for us to grasp the role of moral mechanism in the generation of proactive aggression,so as to find possible moral paths to resist proactive aggression.This study will explore the inhibitory effect of harm aversion on proactive aggression and its brain basis.Specifically speaking,harm aversion refers to the degree of upset caused by an individual’s harm behavior or seeing the harm result,including Outcome aversion and Action aversion.Harm aversion consists of two components:emotion（sympathy and empathy for the victim’s pain）and cognition（a deeply rooted and internalized moral standard）.Starting from the above research background,this study intends to solve the following two problems:（1）Determine the causal relationship between harm aversion and proactive aggression when the individuals that induce harm aversion have less proactive aggression rate and longer aggression decision time compared with the control group（study 1）;（2）What are the key brain regions activated by the process of harm aversion in the laboratory context,and whether these brain activation can predict individuals’proactive aggressive behavior（study 2）.This study developed"harm-gain tasks of harm aversion"with reference to the"harm-gain tasks of moral disengagement"based on pain-gain tasks,which uses harm aversion sentences（for example,"pain caused by long-term electrical stimulation may last for a long time".）to manipulate the level of harm aversion,and measure the level of individuals’proactive aggression,so as to explore the causal relationship between the two.According to the behavioral results of the experimental task,we modified the paradigm appropriately and carried out fMRI experiment to preliminarily explore the activation of brain area and its relationship with proactive aggression in the process of harm aversion under laboratory conditions.Study 1 had 167 effective participants（88 in the experimental group and 79 in the control group）were selected,including 72 males and 95 females,with the age range of 18-25 years（M=20.46,SD=1.61）.In this study,a single factor design was used to manipulate the level of harm aversion by using two different groups of sentences.The results of independent sample t-test showed that the level of harm aversion in the experimental group（M=2.85,SD=0.90）was undoubtedly higher than the scores in the control group（M=1.45,SD=1.01,t（72）=6.32,p<0.001,Cohen’s d=0.60）;the aggression rate of the participants in the experimental group（M=0.52,SD=0.29）was significantly lower than that in the neutral group（M=0.71,SD=0.25,t（165）=4.43,p<0.001,Cohen’s d=0.57）;the aggression response time of the participants in the experimental group（M=1331,SD=284.97）was undoubtedly higher than the scores in the control group（M=1233.05,SD=310.80,t（165）=-2.13,p=0.035,Cohen’s d=0.16）.In study 2,fMRI was used to explore the mechanism of brain activation in the process of harm aversion and its predictive effect on proactive aggressive behavior.In addition to using an inter-subject design similar to study 1,participants were invited to return to the laboratory at an interval of 15-25days to complete another experimental condition,achieving an ABBA balance design within the single factor intra-subjects.The design of both inter-subjects and intra-subjects can not only further verify the conclusion of study 1,but also help to more accurately find the brain area activated by harm aversion.There were 50 active participants in study 2（not repeated with those in study 1）,25 males and 25 females respectively,ranging in age from 19 to 24 years（M=20.06,SD=1.19）.Forty-three participants,including 21 women and 22 men,completed the experiment under another condition,ranging in age from 19 to 24 years（M=20.13,SD=1.29）.Behavior results of study 2 are basically consistent with those of study 1.（1）The behavioral results of between-subjects designs showed that the harm aversion level of the experimental group（M=2.15,SD=0.80）was undoubtedly higher than the scores of the control group（M=0.44,SD=0.35,t（48）=-9.64,p<0.001,Cohen’s d=0.81）;the proactive aggression rate of the experimental group（M=0.39,SD=0.28）was automatically lower than the scores of the control group（M=0.68,SD=0.25,t（48）=3.844,p<0.001,Cohen’s d=0.49）;the response time analysis showed that there was no significant difference between the two groups;（2）The behavior results of within-subjects design showed that the level of harm aversion in the experimental group（M=1.96,SD=0.86）was significantly higher than that in the control group（M=0.54,SD=0.44,t（42）=-8.24,p<0.001,Cohen’s d=0.76）;there was no significant difference in the ratio of proactive aggression between the experimental group（M=0.46,SD=0.28）and the control group（M=0.49,SD=0.33,t（42）=-0.712;p=0.481）;while the analysis of reaction time showed that the aggression reaction time in the experimental group（M=1419.80,SD=252.87）was significantly higher than that in the control group（M=915.20,SD=210.92,t（42）=11.081;p<0.001,Cohen’s d=0.86）;In addition,the participants’brain activation and the degree of correlation with their proactive aggression were different in the two designs of study 2.（a）Between-subjects designs:compared with the baseline,the right medial prefrontal lobe and bilateral temporo-parietal junction area of the same participants were significantly activated in the process of harm aversion.Meanwhile,the activation level of the brain area was negatively correlated with the proactive aggression response time respectively（r₁=0.520,p₁<0.001;r₂=0.578,p₂<0.001;r₃=0.288,p₃=0.007）.（b）Within-subjects design:based on the control condition,the right ventrolateral prefrontal lobe,the right temporo-parietal junction area and the precuneus of the two groups of participants were significantly activated in the process of harm aversion,and the activation level of these brain region were significantly negatively correlated with proactive aggression respectively（r₁=-0.459,p₁=0.001;r₂=-0.324,p₂=0.022;r₃=-0.524,p₃<0.001）.Based on the two studies,the following conclusions are drawn:（1）Harm aversion induced by sentence guidance can resist the aggressive behavior;（2）The key areas of aggression related harm aversion were bilateral temporo-parietal junction area,right ventrolateral prefrontal lobe,right medial prefrontal lobe and anterior cuneiform lobe.