Embedding social dilemmas in intergroup competition reduces free-riding

We study a class of multi-level collective actions, in which each individual is simultaneously engaged in an intragroup conflict and intergroup competition. The intragroup conflict is modeled as an n-person Prisoner’s Dilemma game, in which the dominant strategy is to contribute nothing. The intergroup competition is for an exogenous and commonly known prize shared by members of the winning group. We focus on the effects on the level of contribution of the two most common sharing rules for dividing the prize, equal and proportional. Our results show that (1) embedding the intragroup conflict in intergroup competition markedly reduces free riding; (2) the proportional profit sharing rule significantly outperforms the egalitarian rule, and the difference between the two increases with experience; (3) under egalitarian but not under proportional sharing, there is over-contribution compared to theoretical predictions, and (4) a simple reinforcement-based learning model accounts for the aggregate results of all five experimental conditions.     

Follow-up of victims of one terrorist attack in Israel: ASD, PTSD and the perceived threat of Iraqi missile attacks

The first aim of the study was to examine the relationships between acute stress reactions and post-traumatic reactions following exposure to a terrorist attack. The second was to examine whether exposure to a terrorist attack increases the perceived threat and fear of renewed Iraqi missile attacks. Data were collected at two points in time: during the first month after the exposure to a terrorist attack (N = 54), and four months later (N = 44). Twenty-four percent of the exposed group had acute stress disorder (ASD), and a similar percentage had PTSD. Among participants who had ASD, the chances of developing PTSD were three times greater than among those who had never experienced ASD. Among participants who had been exposed to a terrorist attack and developed PTSD, the perceived threat of an Iraqi missile attack was greater than among those who had been exposed to a terrorist attack but did not develop PTSD, or among the participants in the control group. The discussion deals with the findings in light of the current controversy regarding ASD and the current situation in Israel.     

Posttraumatic Growth in Trauma Recollections of 9/11 Survivors: A Narrative Approach

The relationship between posttraumatic growth (PTG) and adaptation is unclear. This study is the first to examine PTG in trauma narratives of survivors of the World Trade Center (WTC) attacks. Participants recalled their experiences 7 and 18 months post 9/11, and content analysis was conducted to detect PTG. Posttraumatic stress was also measured. PTG was commonly reported. Relating to others and positivity were frequent in the PTSD and non-PTSD group, although less frequent over time in the PTSD. Greater appreciation for life was reported by the non-PTSD group but relatively absent in the PTSD group. Women but not men reported relating to others across time. It appears that there are distinct profiles of growth implicated in distress and adaptation.     

Mothering under political violence: Post-traumatic symptoms,observed maternal parenting practices and child externalising behaviour

Using the family stress model as our conceptual framework, we explored whether observed maternal parenting practices (positive and coercive) account for the associations between mothers' post-traumatic stress symptoms and children's externalising behaviours. Mothers' self-reported post-traumatic stress symptoms, observed maternal practices, and reports of children's externalising behaviour were collected from 123 Israeli mothers and their children, who were exposed to ongoing rocket attacks in southern Israel. A structural equation model revealed that mothers' post-traumatic stress symptoms were linked with greater maternal coercive parenting practices, which in turn were associated with more externalising behaviours in children. The study highlights the crucial role of maternal distress and mothers' parenting skills in the development of externalising behaviours in children exposed to chronic political violence. These results suggest that prevention interventions designed to promote parenting skills for mothers exposed to political violence may be beneficial for children's healthy development.     

Sense of Coherence, Ways of Coping, and Well Being of Married and Divorced Mothers

The study examines sense of coherence and ways of coping as personality resources capable of helping divorced mothers deal with the divorce crisis. The findings show that although mothers from two parent families enjoy a higher sense of well being than divorced mothers, the well being of both groups was predicted by sense of coherence. They also show that mothers with higher sense of coherence used more effective coping strategies and derived more benefit from the strategies they used. The married and divorced mothers have a similar sense of coherence level. More study is needed to ascertain precisely how sense of coherence contributes to well being, as well as to the choice and effectiveness of coping strategies.     

Intergroup competition for the provision of step-level public goods: Effects of preplay communication

Thirty-two groups of three subjects each participated once in an intergroup public goods game (IPG) in which two groups compete for the provision of step-level public goods. Half of the groups were allowed to discuss the conflict before their members decided privately and anonymously whether to contribute their endowments to their group benefit, and half were not given this opportunity. The results show that preplay group discussion enhances the percentage of contributors and changes the players' estimates about the decisions of the other players. The theoretical implications of the results are examined within the framework of a new model which relates the individual decision to contribute or not to the reward structure, altruism, and the individual's belief structure.     

The Ottoman approach to Christians and Christianity in sixteenth‐century Jerusalem

The Ottoman Empire was a Muslim state not only by definition; in many fields it actually implemented Islamic policies. In Ottoman Palestine these policies could be discerned from the early sixteenth century onwards, and they were applied particularly in Jerusalem. Laden with memories of religious conflicts, encompassing a Christian (as well as Jewish) population and their holy sites, it would hardly be surprising to find anti‐Christian acts and perhaps even policies in Jerusalem. The sixteenth‐century formative Ottoman years witnessed several anti‐Christian incidents: expulsion of the Franciscan monks from their convent on Mount Zion in 1551, Muslim attempts to legally seize parts of the Monastery of the Cross near Jerusalem from the Georgians in the early sixties, and during the same years similar threats to the Coptic Dayr al‐Khadr monastery in town. These incidents should not be construed as part of an overall policy, but should rather be seen as illustrations of pressures exerted on the Ottoman authorities by local Muslim zealots. Official policies of the Sultan, and in most cases his actual orders, sought to protect and uphold the Christian presence in Jerusalem. The expulsion from Mount Zion was an exception to the general rule, and even in that case the local authorities provided the Franciscans with an alternative building within the larger Christian complex.     

Quota vs positional power in four-person apex games

In coalition formation experiments, which coalitions will form and how players in coalitions will allocate their jointly gained rewards are typically predicted as a function of the players' relative power. In this paper, we isolated two logically independent sources of a player's power: the player's contribution to the rewards obtainable by coalitions of which he may be a member (“quota power”), and the number of distinct coalitions which a player may join (“positional power”). The separation of the two types of power is clearly shown in apex games, where a single player (Apex) attempts to lure any of the other players (Base) from the coalition of all Bases. A series of four-person computer-controlled apex and nonapex characteristic function games, varying with respect to the relationship of quota power to positional power, were played by 15 quartets of male players. Quota power was strongly manifested in all outcome measures, while positional power appeared only as a bias toward equal allocations of reward when coalitions among players of equal positional power formed. Neither of two social psychological theories that are applicable, pivotal power and weighted probability theory, predicted coalition frequencies. In a test of five solution concepts, the competitive bargaining set predicted payoff allocations better than either of the two aforementioned theories, the kernel, or an equal-split model.