Emma Cohen

Rowers' high: behavioural synchrony is correlated with elevated pain thresholds

Physical exercise is known to stimulate the release of endorphins, creating a mild sense of euphoria that has rewarding properties. Using pain tolerance (a conventional non-invasive assay for endorphin release), we show that synchronized training in a college rowing crew creates a heightened endorphin surge compared with a similar training regime carried out alone. This heightened effect from synchronized activity may explain the sense of euphoria experienced during other social activities (such as laughter, music-making and dancing) that are involved in social bonding in humans and possibly other vertebrates.

Moralistic gods, supernatural punishment and the expansion of human sociality.

Since the origins of agriculture, the scale of human cooperation and societal complexity has dramatically expanded. This fact challenges standard evolutionary explanations of prosociality because well-studied mechanisms of cooperation based on genetic relatedness, reciprocity and partner choice falter as people increasingly engage in fleeting transactions with genetically unrelated strangers in large anonymous groups. To explain this rapid expansion of prosociality, researchers have proposed several mechanisms. Here we focus on one key hypothesis: cognitive representations of gods as increasingly knowledgeable and punitive, and who sanction violators of interpersonal social norms, foster and sustain the expansion of cooperation, trust and fairness towards co-religionist strangers. We tested this hypothesis using extensive ethnographic interviews and two behavioural games designed to measure impartial rule-following among people (n = 591, observations = 35,400) from eight diverse communities from around the world: (1) inland Tanna, Vanuatu; (2) coastal Tanna, Vanuatu; (3) Yasawa, Fiji; (4) Lovu, Fiji; (5) Pesqueiro, Brazil; (6) Pointe aux Piments, Mauritius; (7) the Tyva Republic (Siberia), Russia; and (8) Hadzaland, Tanzania. Participants reported adherence to a wide array of world religious traditions including Christianity, Hinduism and Buddhism, as well as notably diverse local traditions, including animism and ancestor worship. Holding a range of relevant variables constant, the higher participants rated their moralistic gods as punitive and knowledgeable about human thoughts and actions, the more coins they allocated to geographically distant co-religionist strangers relative to both themselves and local co-religionists. Our results support the hypothesis that beliefs in moralistic, punitive and knowing gods increase impartial behaviour towards distant co-religionists, and therefore can contribute to the expansion of prosociality.

Synchrony and exertion during dance independently raise pain threshold and encourage social bonding

Group dancing is a ubiquitous human activity that involves exertive synchronized movement to music. It is hypothesized to play a role in social bonding, potentially via the release of endorphins, which are analgesic and reward-inducing, and have been implicated in primate social bonding. We used a 2 × 2 experimental design to examine effects of exertion and synchrony on bonding. Both demonstrated significant independent positive effects on pain threshold (a proxy for endorphin activation) and in-group bonding. This suggests that dance which involves both exertive and synchronized movement may be an effective group bonding activity.

The evolution of tag-based cooperation in humans: The case for accent

Recent game-theoretic simulation and analytical models have demonstrated that cooperative strategies mediated by indicators of cooperative potential, or “tags,” can invade, spread, and resist invasion by noncooperators across a range of population-structure and cost-benefit scenarios. The plausibility of these models is potentially relevant for human evolutionary accounts insofar as humans possess some phenotypic trait that could serve as a reliable tag. Linguistic markers, such as accent and dialect, have frequently been either cursorily defended or promptly dismissed as satisfying the criteria of a reliable and evolutionarily viable tag. This paper integrates evidence from a range of disciplines to develop and assess the claim that speech accent mediated the evolution of tag-based cooperation in humans. Existing evidence warrants the preliminary conclusion that accent markers meet the demands of an evolutionarily viable tag and potentially afforded a cost-effective solution to the challenges of maintaining viable cooperative relationships in diffuse, regional social networks.

What is Spirit Possession? Defining, Comparing, and Explaining Two Possession Forms

Abstract Reviewing anthropological analyses of possession forms cross-culturally and drawing from recent advances in cognitive psychology, this paper attempts to explain recurrent features of spirit possession. Spirit possession concepts fall into broadly two varieties: one that entails the transformation or replacement of identity (executive possession) and one that envisages possessing spirits as (the cause of) illness and misfortune (pathogenic possession). The cross-culturally recurrent features of these divergent conceptual structures may be explained, at least in part, with reference to distinct processes of human psychology, one set of which deals with the representation of person-identity and another that deals with notions about contamination.

Religion, synchrony, and cooperation

Shared beliefs about supernatural agents and joint engagement in ritual activities are often proposed to engender cohesion and cooperation within religious communities. We report the results of an experiment that investigated the effects of religious-concept priming and synchronous activity among Brazilian drummers. Participants were divided into two between-subjects narrative priming conditions: religious and secular. Within each priming condition, we applied a within-subjects design to investigate effects of solo, group synchronous, and group non-synchronous drumming on endorphin release and cooperation. We found an effect of priming conditions, such that there was a trend toward higher cooperation in the religiously primed group compared to the secularly primed group. We found neither a main effect of the drumming condition nor a drumming-priming interaction effect. Results suggest that behavioral synchrony alone is insufficient to increase cooperation. In light of previous findings, we propose that high levels of physical exertion or social-cognitive mechanisms, such as overlapping task-representation or intentional coordination, are also required for cooperation.

The Evolution of Tag-Based Cooperation in Humans

Recent game-theoretic simulation and analytical models have demonstrated that cooperative strategies mediated by indicators of cooperative potential, or “tags,” can invade, spread, and resist invasion by noncooperators across a range of population-structure and cost-benefit scenarios. The plausibility of these models is potentially relevant for human evolutionary accounts insofar as humans possess some phenotypic trait that could serve as a reliable tag. Linguistic markers, such as accent and dialect, have frequently been either cursorily defended or promptly dismissed as satisfying the criteria of a reliable and evolutionarily viable tag. This paper integrates evidence from a range of disciplines to develop and assess the claim that speech accent mediated the evolution of tag-based cooperation in humans. Existing evidence warrants the preliminary conclusion that accent markers meet the demands of an evolutionarily viable tag and potentially afforded a cost-effective solution to the challenges of maintaining viable cooperative relationships in diffuse, regional social networks.

Movement Synchrony Forges Social Bonds across Group Divides.

Group dynamics play an important role in the social interactions of both children and adults. A large amount of research has shown that merely being allocated to arbitrarily defined groups can evoke disproportionately positive attitudes toward ones in-group and negative attitudes toward out-groups, and that these biases emerge in early childhood. This prompts important empirical questions with far-reaching theoretical and applied significance. How robust are these inter-group biases? Can biases be mitigated by behaviors known to bond individuals and groups together? How can bonds be forged across existing group divides? To explore these questions, we examined the bonding effects of interpersonal synchrony on minimally constructed groups in a controlled experiment. In-group and out-group bonding were assessed using questionnaires administered before and after a task in which groups performed movements either synchronously or non-synchronously in a between-participants design. We also developed an implicit behavioral measure, the Island Game, in which physical proximity was used as an indirect measure of interpersonal closeness. Self-report and behavioral measures showed increased bonding between groups after synchronous movement. Bonding with the out-group was significantly higher in the condition in which movements were performed synchronously than when movements were performed non-synchronously between groups. The findings are discussed in terms of their importance for the developmental social psychology of group dynamics as well as their implications for applied intervention programs.

Seeking a Rapprochement Between Anthropology and the Cognitive Sciences: A Problem-Driven Approach

Beller, Bender, and Medin question the necessity of including social anthropology within the cognitive sciences. We argue that there is great scope for fruitful rapprochement while agreeing that there are obstacles (even if we might wish to debate some of those specifically identified by Beller and colleagues). We frame the general problem differently, however: not in terms of the problem of reconciling disciplines and research cultures, but rather in terms of the prospects for collaborative deployment of expertise (methodological and theoretical) in problem-driven research. For the purposes of illustration, our focus in this article is on the evolution of cooperation.

Interpersonal movement synchrony facilitates pro-social behavior in children's peer-play

The emergence of pro-social behaviors and social interaction skills is a major focus of research on childrens development. Here, we consider one important feature of human social interactions, interpersonal movement synchrony, and explore its effects on pro-sociality among young children. Coordinated movements are a crucial part of mother-infant interactions, with important social effects extending well into childhood. Musical interactions are also known to facilitate bonding between infants and caretakers and pro-sociality among peers. We specifically examine the pro-social effects of interpersonal movement synchrony in a naturalistic peer-play context among 4- to 6-year-old children. We assessed the amount of helping behavior between pairs of children following an activity that they performed synchronously or non-synchronously. Children who engaged in synchronous play, as compared with non-synchronous play, showed significantly more subsequent spontaneous helping behavior. Further, more mutual smiling and eye contact were observed in the synchronous condition and amounts of mutual smiling and eye contact during the movement task correlated with amount of helping behavior observed. Neither measure mediated the condition-wise effects on helping, however. These results are discussed in terms of their contribution to existing literature and their broader implications for the development of pro-sociality and coordinated movements in early childhood.