Not on my team: Medial prefrontal cortex responses to ingroup fusion and unfair monetary divisions

Social environment-based opportunity costs dictate when people leave social interactions

There is an ever-increasing understanding of the cognitive mechanisms underlying how we process others' behaviours during social interactions. However, little is known about how people decide when to leave an interaction. Are these decisions shaped by alternatives in the environment - the opportunity-costs of connecting to other people? Here, participants chose when to leave partners who treated them with varying degrees of fairness, and connect to others, in social environments with different opportunity-costs. Across four studies we find people leave partners more quickly when opportunity-costs are high, both the average fairness of people in the environment and the effort required to connect to another partner. People's leaving times were accounted for by a fairness-adapted evidence accumulation model, and modulated by depression and loneliness scores. These findings demonstrate the computational processes underlying decisions to leave, and highlight atypical social time allocations as a marker of poor mental health.

Dissociating neural sensitivity to target identity and mental state content type during inferences about other minds

Predicting and inferring what other people think and feel (mentalizing) is central to social interaction. Since the discovery of the brain's "mentalizing network", fMRI studies have probed the lines along which the activity of different regions in this network converges and dissociates. Here, we use fMRI meta-analysis to aggregate across the stimuli, paradigms, and contrasts from past studies in order to definitively test two sources of possible sensitivity among brain regions of this network with particular theoretical relevance. First, it has been proposed that mentalizing processes depend on aspects of target identity (whose mind is considered), with self-projection or simulation strategies engaging disproportionately for psychologically close targets. Second, it has been proposed that mentalizing processes depend on content type (what the inference is), with inferences about epistemic mental states (e.g. beliefs and knowledge) engaging different processes than mentalizing about other types of content (e.g. emotions or preferences). Overall, evidence supports the conclusion that different mentalizing regions are sensitive to target identity and content type, respectively, but with some points of divergence from previous claims. Results point to fruitful directions for future studies, with implications for theories of mentalizing.

The Fusion-Secure Base Hypothesis

Identity fusion is traditionally conceptualized as innately parochial, with fused actors motivated to commit acts of violence on out-groups. However, fusion's aggressive outcomes are largely conditional on threat perception, with its effect on benign intergroup relationships underexplored. The present article outlines the fusion-secure base hypothesis, which argues that fusion may engender cooperative relationships with out-groups in the absence of out-group threat. Fusion is characterized by four principles, each of which allows a fused group to function as a secure base in which in-group members feel safe, agentic, and supported. This elicits a secure base schema, which increases the likelihood of fused actors interacting with out-groups and forming cooperative, reciprocal relationships. Out-group threat remains an important moderator, with its presence "flipping the switch" in fused actors and promoting a willingness to violently protect the group even at significant personal cost. Suggestions for future research are explored, including pathways to intergroup fusion.

Pain perception during social interactions is modulated by self-related and moral contextual cues

Despite the growing interest on the effect of the social context on pain, whether and how different facets of interpersonal interactions modulate pain are still unclear. We tested whether personal (i.e., convenient for the self), moral (i.e., equitability of the transaction) or social (i.e., positive vs. negative feedback from others) valence of an interpersonal interaction differentially affects pain and the perceived fairness. Thirty-two healthy participants played the role of Receivers in a Dictator Game, where a player, the Dictator, determined how to divide a payoff between her/himself and the other player, the Receiver. We manipulated the payoff (pain vs. money), the personal valence (favorable vs. unfavorable offer to participants), the moral valence of the offer (from very iniquitous to equitable), and social valence of the Dictator (social acceptance vs. rejection). Moral and personal valence differentially modulated pain. Lower pain was elicited by iniquity, but also by favorable offers. Moreover, unfavorable offers in the economic game were rated as more unfair, whereas only very iniquitous offers elicited such ratings in the pain game, suggesting that participants valued when Dictators endured extra pain for their benefit. Together, we show that the valence of a social interaction at different levels can independently modulate pain and fairness perception.

Depletion manipulations decrease openness to dissent via increased anger

We investigated a potential outcome of ego depletion manipulations and an important factor behind cooperative failure: a lack of openness to others' dissenting opinions. Across five studies in a variety of task settings, we examined the effect of depletion manipulations on openness to dissent and investigated two negative emotions as potential mediators of this process: fatigue and anger. The results demonstrated a negative effect of depletion manipulations on openness to dissent through increased anger rather than fatigue (Studies 1-5). In Studies 3 and 4, we also eliminated perceived trust towards a task counterpart as a significant mediator of the relationship between depletion manipulations and openness to dissent. These findings help clarify the nature of ego depletion manipulations and shed light on why individuals may fail to consider others' dissenting opinions and, thus, fall short of achieving cooperation.

Not on my team: Medial prefrontal cortex responses to ingroup fusion and unfair monetary divisions

OBJECTIVE

People are highly attuned to fairness, with people willingly suffering personal costs to prevent others benefitting from unfair acts. Are fairness judgments influenced by group alignments? A new theory posits that we favor ingroups and denigrate members of rival outgroups when our personal identity is fused to a group. Although the mPFC has been separately implicated in group membership and fairness processing, it is unclear whether group alignments affect medial prefrontal cortex (mPFC) activity in response to fairness. Here, we examine the contribution of different regions of the mPFC to processing from ingroup and outgroup members and test whether its response differs depending on how fused we are to an ingroup.

METHODS

Subjects performed rounds of the Ultimatum Game, being offered fair or unfair divisions of money from supporters of the same soccer team (ingroup), the fiercest rival (outgroup) or neutral individuals whilst undergoing functional Magnetic Resonance Imaging (fMRI).

RESULTS

Strikingly, people willingly suffered personal costs to prevent outgroup members benefitting from both unfair and fair offers. Activity across dorsal and ventral (VMPFC) portions of the mPFC reflected an interaction between fairness and group membership. VMPFC activity in particular was consistent with it coding one's fusion to a group, with the fairness by group membership interaction correlating with the extent that the responder's identity was fused to the ingroup.

CONCLUSIONS

The influence of fusion on social behavior therefore seems to be linked to processing in the VMPFC.

Dying for the group: Towards a general theory of extreme self-sacrifice

Whether upheld as heroic or reviled as terrorism, people have been willing to lay down their lives for the sake of their groups throughout history. Why? Previous theories of extreme self-sacrifice have highlighted a range of seemingly disparate factors, such as collective identity, outgroup hostility, and kin psychology. In this paper, I attempt to integrate many of these factors into a single overarching theory based on several decades of collaborative research with a range of special populations, from tribes in Papua New Guinea to Libyan insurgents and from Muslim fundamentalists in Indonesia to Brazilian football hooligans. These studies suggest that extreme self-sacrifice is motivated by identity fusion, a visceral sense of oneness with the group, resulting from intense collective experiences (e.g., painful rituals or the horrors of frontline combat) or from perceptions of shared biology. In ancient foraging societies, fusion would have enabled warlike bands to stand united despite strong temptations to scatter and flee. The fusion mechanism has often been exploited in cultural rituals, not only by tribal societies but also in specialized cells embedded in armies, cults, and terrorist organizations. With the rise of social complexity and the spread of states and empires, fusion has also been extended to much larger groups, including doctrinal religions, ethnicities, and ideological movements. Explaining extreme self-sacrifice is not only a scientific priority but also a practical challenge as we seek a collective response to suicide, terrorism, and other extreme expressions of outgroup hostility that continue to bedevil humanity today.