SignificanceBiologists and social scientists have long tried to understand why some societies have more fluid and open interpersonal relationships—differences in relational mobility—and how those differences influence individual behaviors. We measure relational mobility in 39 societies and find that relationships are more stable and hard to form in east Asia, North Africa, and the Middle East, while they are more fluid in the West and Latin America. Results show that relationally mobile cultures tend to have higher interpersonal trust and intimacy. Exploring potential causes, we find greater environmental threats (like disease and warfare) and sedentary farming are associated with lower relational mobility. Our society-level index of relational mobility for 39 societies is a resource for future studies.

Willingness to lay down one’s life for a group of non-kin, well documented historically and ethnographically, represents an evolutionary puzzle. Building on research in social psychology, we develop a mathematical model showing how conditioning cooperation on previous shared experience can allow individually costly pro-group behavior to evolve. The model generates a series of predictions that we then test empirically in a range of special sample populations (including military veterans, college fraternity/sorority members, football fans, martial arts practitioners, and twins). Our empirical results show that sharing painful experiences produces “identity fusion” – a visceral sense of oneness – which in turn can motivate self-sacrifice, including willingness to fight and die for the group. Practically, our account of how shared dysphoric experiences produce identity fusion helps us better understand such pressing social issues as suicide terrorism, holy wars, sectarian violence, gang-related violence, and other forms of intergroup conflict.

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There is considerable evidence for the effectiveness of mind–body interventions (MBIs) in improving mental and physical health, but the molecular mechanisms of these benefits remain poorly understood. One hypothesis is that MBIs reverse expression of genes involved in inflammatory reactions that are induced by stress. This systematic review was conducted to examine changes in gene expression that occur after MBIs and to explore how these molecular changes are related to health. We searched PubMed throughout September 2016 to look for studies that have used gene expression analysis in MBIs (i.e., mindfulness, yoga, Tai Chi, Qigong, relaxation response, and breath regulation). Due to the limited quantity of studies, we included both clinical and non-clinical samples with any type of research design. Eighteen relevant studies were retrieved and analyzed. Overall, the studies indicate that these practices are associated with a downregulation of nuclear factor kappa B pathway; this is the opposite of the effects of chronic stress on gene expression and suggests that MBI practices may lead to a reduced risk of inflammation-related diseases. However, it is unclear how the effects of MBIs compare to other healthy interventions such as exercise or nutrition due to the small number of available studies. More research is required to be able to understand the effects of MBIs at the molecular level.

Across three studies, we examined the role of shared negative experiences in the formation of strong social bonds—identity fusion—previously associated with individuals' willingness to self-sacrifice for the sake of their groups. Studies 1 and 2 were correlational studies conducted on two different populations. In Study 1, we found that the extent to which Northern Irish Republicans and Unionists experienced shared negative experiences was associated with levels of identity fusion, and that this relationship was mediated by their reflection on these experiences. In Study 2, we replicated this finding among Bostonians, looking at their experiences of the 2013 Boston Marathon Bombings. These correlational studies provide initial evidence for the plausibility of our causal model; however, an experiment was required for a more direct test. Thus, in Study 3, we experimentally manipulated the salience of the Boston Marathon Bombings, and found that this increased state levels of identity fusion among those who experienced it negatively. Taken together, these three studies provide evidence that shared negative experience leads to identity fusion, and that this process involves personal reflection.

Fear of death features in both historical and contemporary theories of religion, but the relationship between death anxiety and religious belief is still ambiguous, largely due to the use of inappropriate or imprecise measures. The current studies therefore aimed to develop a valid, targeted measure of respondents' tendency towards religious belief, the ‘Supernatural Belief Scale’ (SBS), and to use the SBS to examine the relation between death anxiety and religious belief. Results indicate that the SBS shows high reliability and convergent validity and that its relation to death anxiety depends on participants' religious identification: ‘religious’ participants fear death less the stronger their religious beliefs, whereas ‘non‐religious’ participants are more inclined towards religious belief the more they fear death. These studies contribute a new measurement tool for research on religious belief and provide a starting point for an experimental integration of discrepant research findings. Copyright © 2013 European Association of Personality Psychology

Previous research has found that behavioural synchrony between people leads to greater prosocial tendencies towards co-performers. In this study, we investigated the scope of this prosocial effect: does it extend beyond the performance group to an extended ingroup (extended parochial prosociality) or even to other people in general (generalized prosociality)? Participants performed a simple rhythmic movement either in time (synchrony condition) or out of time (asynchrony condition) with each other. Before and during the rhythmic movement, participants were exposed to a prime that made salient an extended ingroup identity. After the task, half of the participants had the opportunity to help an extended ingroup member; the other half had the opportunity to help an outgroup member. We found a main effect of our synchrony manipulation across both help targets suggesting that the prosocial effects of synchrony extend to non-performers. Furthermore, there was a significantly higher proportion of participants willing to help an outgroup member after moving collectively in synchrony. This study shows that under certain intergroup contexts synchrony can lead to generalized prosociality with performers displaying greater prosociality even towards outgroup members.

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