Neural Activity During Social Exclusion: An Exploratory Examination

Social exclusion has been brought to the forefront of media attention in recent years due to the recent tragedies like campus shootings and cyberbullying on social networking websites. In order to gain a deeper understanding of social exclusion, this study examined the relation between social exclusion and event-related brain potential (ERP) activity. ERPs were collected while participants completed three blocks of the Cyberball paradigm during which they experienced situations of social inclusion, exclusion, and re-inclusion. This well-established paradigm mimics actual social behavior experienced in real-world situations. Results showed larger N2 and smaller P3 amplitudes during throws where participants were excluded compared to when they were included, regardless of the interaction’s overall context (inclusion, exclusion, re-inclusion), suggesting the conflict-driven “neural alarm” and the allocation of attention are determined more by specific events within the interaction rather than the larger context of the social exchange. Further, during the exclusionary interaction, both the N2 and P3 showed larger amplitudes in the earlier stages of exclusion compared to the later stages, suggesting heightened early sensitivity for both components, and P3 amplitude was larger to exclusionary events compared to the two inclusionary interactions, indicating a contextual influence of exclusion. These findings suggest that discrete events occurring during a social interaction may provide additional insights into social exclusion compared to more global “inclusionary” or “exclusionary” classifications of social interactions. Running Head: NEURAL ACTIVITY DURING SOCIAL EXCLUSION 3 Neural Activity During Social Task Performance: An Exploratory Examination Human beings, by nature, are social creatures (Williams, Forgas, von Hippel, & Zadro, 2005). As such, we have evolved to rely on our many complex social relationships as a means to our survival. While these relationships can foster in us the sentiments of friendship, connection, belongingness, love, and even survival, the smallest strains in our social relationships can cause us to feel ostracized (Williams et al., 2005). Given the complexity and number of social interactions we encounter on a daily basis, we are susceptible to social exclusion in many different forms. Social exclusion refers to not being included in a social interaction. We may act as perpetrators and give someone the cold shoulder, end a romantic relationship, or distance ourselves from other individuals (Leary, Kowalski, Smith, & Phillips, 2003). We also find ourselves as victims of this exclusion. Other people may avoid our eye contact, fail to return our emails, or choose not to invite us to social gatherings. Regardless of intention, all of these actions have the potential to elicit a sense of distress in the recipient (Wesselmann, Bagg, & Williams, 2009). In a study conducted in Australia, participants reported experiencing social exclusion in some form at least once a day (Williams, Wheeler, & Harvey, 2001; as cited in Williams, 2007). Cross cultural research demonstrates that social exclusion is experienced by everyone in varying degrees, making it important to study the negative outcomes it causes in our lives. Recent research has suggested that social exclusion leads to psychological distress, negative affect, and is one of the greatest predictors for future aggression (Leary et al., 2003). Current research has suggested that humans possess a fast-acting detection system for exclusion which allows individuals to prevent future social rejections (Wesselmann, Bagg, & Williams, 2009). In order to further understand the degree to which the brain processes acts of exclusion, as well as methods of combating its aversive effects, this study explores the effects of social Running Head: NEURAL ACTIVITY DURING SOCIAL EXCLUSION 4 exclusion by examining event-related brain potentials (ERPs) associated with social exclusion. Notably, much prior research in this domain has relied primarily on either self-report or functional magnetic resonance imaging (fMRI) measures as a means to collect data. While both of these methods are useful, self-report data are limited as they only allow for the examination of behaviors and feelings of the participant. Meanwhile, fMRI data only allow for examination of specific brain areas after exclusion occurs and does not have the temporal sensitivity to monitor moment-to-moment events within a social interaction. ERP analysis allows us to obtain more precise information about the exact time course of neural events related to exclusion. These millisecond-to-millisecond recordings allow us to examine minute changes in brain activity as they are occurring. To better understand the relationship between social exclusion and neuroelectric activity, it is necessary to examine existing literature on the social nature of humans, the detrimental effects of social exclusion, and current social monitoring theories. First, an overview of the evolution of humans as social creatures will be provided to establish why social inclusion is vital to survival. Second, the detrimental effects of social exclusion will be discussed to establish how social exclusion is damaging to behavioral, physical, and psychological functioning. Next, the current theoretical models of social monitoring processes will be introduced to provide a background for detection of social exclusion and the neural activity involved in these processes. Lastly, recent studies will be reviewed in order to demonstrate the gaps in our understanding of these neural processes and provide justification for the study currently being proposed. Humans as Social Animals According to Williams, Forgas, Von Hippel, & Zadro (2005), a primitive need for social inclusion led to the development of an innate system, involving cognitive, behavioral, and Running Head: NEURAL ACTIVITY DURING SOCIAL EXCLUSION 5 emotional processes, so that humans would be better equipped to recognize social rejection. Since the beginning of time, humans have been living as social creatures. It was necessary for primitive beings to communicate and socialize in order to survive. As a member of one of these primitive social groups, humans were able to collaborate in order to fulfill their most basic needs of livelihood (Williams et al., 2005). By working together to protect themselves from predators, construct shelter, find means to sustenance, and various other activities, they were able to ensure their lengthened vitality as well as a heightened quality of life (Lakin & Chartrand, 2005). Living without group membership benefits would be extremely costly (Williams et al., 2005). According to Gruter and Masters (1986), exclusion of a social creature equated to death (as cited in Williams, 2007). The immense vulnerability to the elements and attack of animals or other savage beings warranted association with others as a means of protection (Williams et al., 2005). Increased association with other beings was also helpful in procuring sustenance. Having more hunters and gatherers in a society equaled a higher probability of finding food (Williams et al., 2005). In order to maintain their membership status, humans learned to sacrifice their own needs for collective group needs (Baumeister & DeWall, 2005). Rejection from this social group would have led to the ostracized person's demise (Williams et al., 2005). One of the most devastating features of rejection is that it prevents excluded individuals from pursuing their innate drive to procreate (Williams et al., 2005). This most basic of instincts requires that humans form a bond with at least one member of the opposite sex in order to continue their clan and race as a whole. Smith and colleagues (2003) conducted a study of the Meriam tribe of the island Mer in which they found that the more successful hunters of the tribe achieved higher reproductive success (Smith, Bird, & Bird, 2003). This success included an earlier onset of reproduction, higher quality reproductive mates, and an overall increased average Running Head: NEURAL ACTIVITY DURING SOCIAL EXCLUSION 6 number of mates (Smith et al., 2003). Because these hunters were more socially accepted than other less successful tribesmen, they received heightened reproductive and social benefits (Smith et al., 2003). Though interpersonal relationships may have roots in procreation and survival of the species, the relationships between humans have become increasingly complex over time. As our means of communication, intelligence, and technology evolved, so have our social relationships (Williams et al., 2005). These novel means allow us to rely less directly on others for survival. These new relationships have made living more efficient but also complex due to our indirect relationships with others (Williams et al., 2005). Through the diversification of labors and advances in technology, we are permitted to become specialized in our jobs. For example, inhabitants of industrialized nations rarely resort to hunting as a primary means of providing nourishment for our families. Instead, we rely on some distant cattle farmer to raise and subsequently kill our meat for us. After the meat has been cleaned and rendered ready for cooking, we go to the butcher and buy this meat for a modest sum. This extremely complex cascade of events can also be applied to many other routine activities in modern society. Despite this diversification of societal roles and duties, there still exists a great potential for social exclusion (Williams et al., 2005). Cyberbullying, defined as aggressive behavior or intentional harm-causing behavior taking place in cyberspace, is one phenomenon that has gained more recent attention (Huang & Chou, 2010). This form of bullying can occur in an even more powerful way than physical schoolhouse bullying (Huang & Chou, 2010). While victims of physical bullying ar