The Influence Of Social Class On Aggression And Its Mechanism

Growing up and living in different social and economic contexts considerably impacts people’s thoughts,feelings,and behaviors.Over the past decades,a large body of research has linked social class to aggression.Having a lower social class is a risk factor for the increased likelihood of aggression.Compared with the higher class,the living conditions of lower-class people are generally more threatening,unpredictable,and resource-deprived.Thus,lower-class individuals may develop several behavioral patterns,such as aggression,to adapt to these circumstances.However,not all findings about the association between class and aggression have been consistent,with some studies having identified a negative relationship and others having identified a positive relationship or no relationship at all.These complex interconnections imply that further in-depth research is required.The social class is a long-standing social phenomenon.Whether to maintain positive inter-group relations or social stability and development,it is of great practical significance to explore the influence of social class on aggression and its mechanism.This dissertation focused on social class and aimed to systematically explore the influence of social class on aggression and its mechanism through four studies(including seven specific studies).The first study used a meta-analytical procedure to explore the relationship between social class and aggression to clarify previously mixed findings.We found a significant negative relationship between social class and aggression;although small,this effect is reliable.The highly heterogeneous data indicated that the class/aggression link could change with context,suggesting powerful moderators.Moderator analyses indicated that study-level(e.g.,publication status,type of study,and national differences),sample-level(e.g.,age),class-level(e.g.,type,assessment,and source of social class),and aggression-level(e.g.,type of aggression and target’s responsibility)characteristics accounted for heterogeneity in the relationship.At the study level,social class predicted aggression more strongly in Western cultures than in Eastern ones.Additionally,the findings identified stronger negative associations between class and aggression in lower power distance,more individualistic,and looser cultures.At the sample level,the magnitude of correlation between class and aggression increased with age.At the class level,the subjective social class(SSC)-aggression relation was larger than the objective social class(OSC)-aggression relation.For the OSC,the effect sizes for education and the composite indicator were higher than those for income.Regarding SSC,the effect size using the Mac Arthur ladder scale was significantly larger than that using the perceived category scale.Our analyses suggest that studies measuring social class from one’s own characteristics showed a significantly larger effect size than studies measuring family social class.We further found that in studies that examined family social class,the effect size was larger if the social class data came directly from parents rather than indirectly from students.At the aggression level,the results showed that social class was more strongly related to aggressive affect than aggressive behavior.In addition,people of a lower social class not only displayed increased aggression toward the target who was responsible for evoking feelings of a lower social class,but also toward an innocent party who was not responsible.The moderation analysis further dissected this issue by demonstrating that the effect of social class on aggression toward the responsible target was significantly larger than that toward the innocent target.To avoid the potential loss of important information,the second study explored the association between social class and aggression by simultaneously assessing aggressive and prosocial behaviors within the same study.By using anonymous questionnaires,Study 2examined the relationship between social class and aggression.The results showed that subjective class was significantly negatively correlated with trait aggression.In addition,the mediation analysis showed that social class might have an impact on trait aggression through the serial mediation of sense of control and negative affect.Experiments 3 and 4 used a new paradigm,the Tangram Help/Hurt Task(THHT),to measure aggressive and prosocial behavior simultaneously.We also manipulated the participants’ subjective class to examine the causal relationship between social class and aggressive behavior.Using the “Comparison” method,Experiment 3 found that social class did not significantly influence aggressive behavior.However,the results showed that low-class people behaved more aggressively than high-class people when the effect of prosocial behavior was statistically controlled.In addition,although the sense of(loss of)control after class manipulation was associated with lower positive affect and higher negative affect,which led to an increase in subsequent aggressive behavior,we did not find the same serial mediation of sense of control and negative affect as in Study 2.Finally,we found that participants’ loss of control was reduced after making an aggressive response,but we failed to prove that the effect of social class on post-aggression control was serially mediated by pre-aggression control,negative affect,and aggressive behavior.Therefore,the hypothesis that aggressive behavior can compensate for the loss of control has not been well verified.In Experiment 4,we employed a different approach to manipulate the participants’ subjective social class.Using the “Feedback” procedure,Experiment 4 employed an additional control condition in which the participants learned the(false)feedback that they had a class rank similar to that of others.Social class experiences were found to significantly affect aggressive behavior,regardless of whether prosocial behavior was statistically controlled,with low-class people exhibiting more aggressive behavior than high-class people.In addition,the results showed that the aggressive behavior of the medium-class group was not significantly different from that of the low-and high-class groups.Therefore,it may be that the lower-class experience increases aggressive behavior,while the higher-class experience simultaneously decreases aggressive behavior.Mediation analysis found that social class may influence aggressive behavior through the serial process of sense control and negative affect,as in Study 2.In addition,we demonstrated the role of low-class individuals’ aggressive behavior in compensating for the loss of control.On the one hand,we found participants’ loss of control was reduced after making an aggressive response.On the other hand,the results showed that the effect of social class on post-aggression control was serially mediated by pre-aggression control,negative affect,and aggressive behavior(instead of prosocial behavior).That is,compared with the high-class people,more loss of control and negative affect were experienced by low-class people,who were then associated with a decreased loss of control by exhibiting more aggressive rather than prosocial behavior.The third study examined the effect of social class on aggression using indirect measures of aggressive cognition.Two studies provided causal evidence that the experience of a lower class would increase not only people’s explicit aggressive behaviors but also their implicit aggression.Using the “Comparison” method,Experiment 5 found that low-class participants had stronger associations between the concepts of “Me” and “Aggression” than high-class participants.Experiment 6 used the “Feedback” method to manipulate participants’ social class and employed a control group.The results also showed that the low-class participants had a significantly higher level of implicit aggression than the high-class participants.Experiment 6extended the findings of Experiment 5,showing that the implicit aggression of medium-class participants was not significantly different from that of low-and high-class participants,indicating that lower-class experiences may increase implicit aggression,while higher-class experiences simultaneously decrease implicit aggression.In addition,social mobility belief and agreeableness had significant moderating effects on the relationship between social class and implicit aggression.When social mobility belief/agreeableness was relatively high,no significant difference in implicit aggression was found between medium-and high-class participants,whereas the implicit aggression of low-class participants was significantly higher than that of high-class participants.However,when social mobility belief/agreeableness was relatively low,the implicit aggression of medium-class participants was significantly higher than that of high-class participants,whereas the difference between the high-and low-class participants was not significant.The fourth study examined neural activity during provocation and aggressive responses among people from different social classes.Participants completed the Point Subtraction Aggression Paradigm while undergoing functional magnetic resonance imaging(f MRI).The behavioral data revealed that low-class participants behaved more aggressively toward provocative opponents than did high-class participants,as reflected by the increased button press to reduce their opponents’ points.We initially tested task-related brain reactivity using regions of interest(ROI)analyses across all participants.Provocation(vs.“baseline”)yielded significant activity in the orbitofrontal cortex(OFC),anterior cingulate cortex(ACC),and amygdala.In contrast,aggressive responses(vs.“baseline”)yielded significant activity in the striatum and insula.We then extracted the parameter estimates from the contrasts for each of the significantly activated clusters within each ROI to analyze group differences.We found that low-class participants had significantly higher reactivity to provocation in the OFC and ACC than high-class participants.During aggressive responses,low-class participants had more activity in the striatum and insula than high-class participants.The relationship between social class and aggression was moderated by OFC and ACC activity to provocation;that is,low-class participants behaved more aggressively than high-class participants when OFC/ACC activity was relatively low.However,this difference was not significant when OFC/ACC activity was higher.Four studies consistently reported an overall negative relationship between social class and aggression.Lower-class people showed significantly higher levels of aggressive behavior and cognition than higher-class people.In addition,the aggression of lower-class people may compensate for the loss of control,accompanied by more reward experiences.Based on the existing results,we preliminarily proposed a Threat Response Model of Aggression to explain the mechanism between social class and aggression.Threat contexts will often bring dangers and aversive experiences to individuals,and they may thus develop covarying sets of psychological and physiological adaptations to cope with threat contexts.Aggression is an adaptive strategy used by lower-class people to adapt to environmental threats.This dissertation contributes to the understanding of class differences with regard to aggression;the increased aggression of lower-class individuals may be an adaptive response to their circumstances rather than to their essential characteristics,and the class/aggression link should be considered in particular contexts.Our study also provides insights into how the increased aggression of lower-class people and the tendency toward class solidification could be reduced.