Sonja Vogt

Viewing men's faces does not lead to accurate predictions of trustworthiness

The evolution of cooperation requires some mechanism that reduces the risk of exploitation for cooperative individuals. Recent studies have shown that men with wide faces are anti-social, and they are perceived that way by others. This suggests that people could use facial width to identify anti-social men and thus limit the risk of exploitation. To see if people can make accurate inferences like this, we conducted a two-part experiment. First, males played a sequential social dilemma, and we took photographs of their faces. Second, raters then viewed these photographs and guessed how second movers behaved. Raters achieved significant accuracy by guessing that second movers exhibited reciprocal behaviour. Raters were not able to use the photographs to further improve accuracy. Indeed, some raters used the photographs to their detriment; they could have potentially achieved greater accuracy and earned more money by ignoring the photographs and assuming all second movers reciprocate.

Female genital cutting is not a social coordination norm

New data from Sudan question an influential approach to reducing female genital cutting The World Health Organization defines female genital cutting as any procedure that removes or injures any part of a females external genitalia for nonmedical reasons (1). Cutting brings no documented health benefits and leads to serious health problems. Across six African countries, for example, a cohort of 15-year-old girls is expected to lose nearly 130,000 years of life because of cutting (2). We report data that question an influential approach to promoting abandonment of the practice.

Changing cultural attitudes towards female genital cutting

As globalization brings people with incompatible attitudes into contact, cultural conflicts inevitably arise. Little is known about how to mitigate conflict and about how the conflicts that occur can shape the cultural evolution of the groups involved. Female genital cutting is a prominent example. Governments and international agencies have promoted the abandonment of cutting for decades, but the practice remains widespread with associated health risks for millions of girls and women. In their efforts to end cutting, international agents have often adopted the view that cutting is locally pervasive and entrenched. This implies the need to introduce values and expectations from outside the local culture. Members of the target society may view such interventions as unwelcome intrusions, and campaigns promoting abandonment have sometimes led to backlash as they struggle to reconcile cultural tolerance with the conviction that cutting violates universal human rights. Cutting, however, is not necessarily locally pervasive and entrenched. We designed experiments on cultural change that exploited the existence of conflicting attitudes within cutting societies. We produced four entertaining movies that served as experimental treatments in two experiments in Sudan, and we developed an implicit association test to unobtrusively measure attitudes about cutting. The movies depart from the view that cutting is locally pervasive by dramatizing members of an extended family as they confront each other with divergent views about whether the family should continue cutting. The movies significantly improved attitudes towards girls who remain uncut, with one in particular having a relatively persistent effect. These results show that using entertainment to dramatize locally discordant views can provide a basis for applied cultural evolution without accentuating intercultural divisions.

Trust, Cohesion, and Cooperation After Early Versus Late Trust Violations in Two-Person Exchange: The Role of Generalized Trust in the United States and Japan

We examine how the timing of trust violations affects cooperation and solidarity, including trust and relational cohesion. Past studies that used repeated Prisoner’s Dilemmas suggest that trust violations are more harmful when they occur in early rather than later interactions. We argue that this effect of early trust violations depends on cultural and individual differences in generalized trust. A laboratory study from high- and low-trust cultures (the United States vs. Japan) supported our claim. First, early trust violations were more harmful than late trust violations, but only for Americans; the pattern reversed for Japanese. Second, these patterns were mediated by individual differences in generalized trust. Finally, generalized trust also moderated the effect of trust violations in the United States but not Japan. By demonstrating that generalized trust is not only lower but also less important in low-trust cultures, our research advances our understanding of how culture affects the development of solidarity in exchange relations.

C-peptide induces human renal mesangial cell proliferation in vitro, activating Src-kinase, PI-3 kinase and ERK1/2

BACKGROUND Elevated levels of C-peptide have been found in patients with insulin resistance and early type 2 diabetes. These patients are at greater risk to develop micro- and macrovascular complications. Since diabetic nephropathy involves glomerular hyperproliferation, the present study evaluates the role of C-peptide on human renal mesangial cell proliferation. METHODS AND RESULTS C-peptide induces proliferation of human renal mesangial cells in a concentration-dependent manner with a maximal 2.6±0.4-fold induction at 10 nmol/L (P<0.05 compared with unstimulated cells; n=6), as revealed by [3H]-thymidine incorporation experiments. The proliferative effect of C-peptide is prevented by Src-kinase inhibitor-PP2, PI-3 kinase inhibitor-LY294002, and the ERK1/2 inhibitor-U126. Moreover, C-peptide induces phosphorylation of Src, as well as activation of PI-3 kinase and ERK1/2. Furthermore, C-peptide induces cyclin D1 expression as well as phosphorylation of retinoblastoma protein (Rb). CONCLUSIONS These results demonstrate an active role of C-peptide on the proliferation of human renal mesangial cells in vitro involving PI-3 kinase and MAP kinase signaling pathways, suggesting a possible role of C-peptide in glomerular hyperproliferation in patients with diabetic nephropathy.

The risk of female genital cutting in Europe: Comparing immigrant attitudes toward uncut girls with attitudes in a practicing country

Worldwide, an estimated 200 million girls and women have been subjected to female genital cutting. Female genital cutting is defined as an intentional injury to the female genitalia without medical justification. The practice occurs in at least 29 countries in Africa, the Middle East, and Asia. In addition, globalization and migration have brought immigrants from countries where cutting is commonly practiced to countries where cutting is not traditionally practiced and may even be illegal. In countries receiving immigrants, governments and development agencies would like to know if girls with parents who immigrated from practicing countries are at risk of being cut. Risk assessments, for example, could help governments identify the need for programs promoting the abandonment of cutting among immigrants. Extrapolating from the prevalence and incidence rates in practicing countries, however, is generally not sufficient to guarantee a valid estimate of risk in immigrant populations. In particular, immigrants might differ from their counterparts in the country of origin in terms of attitudes toward female genital cutting. Attitudes can differ because migrants represent a special sample of people from the country of origin or because immigrants acculturate after arriving in a new country. To examine these possibilities, we used a fully anonymous, computerized task to elicit implicit attitudes toward female genital cutting among Sudanese immigrants living in Switzerland and Sudanese people in Sudan. Results show that Sudanese immigrants in Switzerland were significantly more positive about uncut girls than Sudanese in Sudan, and that selective migration out of Sudan likely contributed substantially to this difference. We conclude by suggesting how our method could potentially be coupled with recent efforts to refine extrapolation methods for estimating cutting risk among immigrant populations. More broadly, our results highlight the need to better understand how heterogeneous attitudes can affect the risk of cutting among immigrant communities and in countries of origin.

The Impact of Third-Party Information on Trust: Valence, Source, and Reliability.

Economic exchange between strangers happens extremely frequently due to the growing number of internet transactions. In trust situations like online transactions, a trustor usually does not know whether she encounters a trustworthy trustee. However, the trustor might form beliefs about the trustees trustworthiness by relying on third-party information. Different kinds of third-party information can vary dramatically in their importance to the trustor. We ran a factorial design to study how the different characteristics of third-party information affect the trustor’s decision to trust. We systematically varied unregulated third-party information regarding the source (friend or a stranger), the reliability (gossip or experiences), and the valence (positive or negative) of the information. The results show that negative information is more salient for withholding trust than positive information is for placing trust. If third-party information is positive, experience of a friend has the strongest effect on trusting followed by friend’s gossip. Positive information from a stranger does not matter to the trustor. With respect to negative information, the data show that even the slightest hint of an untrustworthy trustee leads to significantly less placed trust irrespective of the source or the reliability of the information.

Social support among heterogeneous partners

Abstract This paper derives hypotheses on how dyadic social support is affected by heterogeneity of the actors. We distinguish heterogeneity with respect to three parameters. First, the likelihood of needing support; second, the benefits from support relative to the costs for providing support; and, third, time preferences. The hypotheses are based on a game theoretic analysis of an iterated Support Game. We predict that, given homogeneity in two of these parameters, the prospect for mutual support is optimal if actors are homogeneous with respect to the third parameter as well. Second, under heterogeneity with respect to two of the parameters, support is most likely if there is a specific heterogeneous distribution with respect to the other parameter that ‘compensates’ for the original heterogeneity. Third, under weak conditions, the overall optimal condition for mutual support is full homogeneity of the actors.

Behavioural homogenization with spillovers in a normative domain

The importance of culture for human social evolution hinges largely on the extent to which culture supports outcomes that would not otherwise occur. An especially controversial claim is that social learning leads groups to coalesce around group-typical behaviours and associated social norms that spill over to shape choices in asocial settings. To test this, we conducted an experiment with 878 groups of participants in 116 communities in Sudan. Participants watched a short film and evaluated the appropriate way to behave in the situation dramatized in the film. Each session consisted of an asocial condition in which participants provided private evaluations and a social condition in which they provided public evaluations. Public evaluations allowed for social learning. Across sessions, we randomized the order of the two conditions. Public choices dramatically increased the homogeneity of normative evaluations. When the social condition was first, this homogenizing effect spilled over to subsequent asocial conditions. The asocial condition when first was thus alone in producing distinctly heterogeneous groups. Altogether, information about the choices of others led participants to converge rapidly on similar normative evaluations that continued to hold sway in subsequent asocial settings. These spillovers were at least partly owing to the combined effects of conformity and self-consistency. Conformity dominated self-consistency when the two mechanisms were in conflict, but self-consistency otherwise produced choices that persisted through time. Additionally, the tendency to conform was heterogeneous. Females conformed more than males, and conformity increased with the number of other people a decision-maker observed before making her own choice.

Zur Dynamik prosozialen Verhaltens in einem asymmetrischen sozialen Dilemma: ein Beitrag zur experimentellen Spieltheorie The Dynamics of Pro-social Behavior in an Asymmetric Social Dilemma: A Behavioral Game-Theoretic Approach

Zusammenfassung In diesem Beitrag untersuchen wir prosoziales Verhalten im Sinne wechselseitiger Hilfeleistungen. Als formales Modell verwenden wir ein asymmetrisches wiederholtes Solidaritätsspiel zwischen zwei Akteuren. Wir modellieren Asymmetrie in drei Dimensionen: (1.) Nutzen, den ein Akteur aus der Hilfeleistung des anderen zieht, (2.) Kosten der eigenen Hilfeleistung und (3.)Wahrscheinlichkeit, mit der ein Akteur Hilfe benötigt. Wir untersuchen die Effekte von Asymmetrie auf die Dynamik wechselseitiger Hilfeleistungen im Verlauf des Spiels. Wir nehmen an, dass die Häufigkeit, mit der sich die Akteure helfen, vom Nutzen und den Kosten der Hilfeleistungen sowie von der Wahrscheinlichkeit abhängt, Hilfe zu benötigen. Unser Beitrag zur Theoriebildung ist ein einfaches adaptives Verhaltensmodell für die Erklärung wechselseitiger Hilfeleistungen, das an das Forschungsprogramm der experimentellen Spieltheorie („behavioral game theory“) anschließt. Wir präsentieren zwei Varianten eines solchen Modells: eine sozialpsychologisch inspirierte Variante und eine Variante, die auf spieltheoretischen Verhandlungsmodellen beruht. Unser Modell ist robust in dem Sinn, dass beide Varianten zu ähnlichen Vorhersagen führen. Empirische Daten aus zwei Laborexperimenten bestätigen diese Vorhersagen. Summary This contribution examines pro-social behavior in social support relations. Such relations are modeled as an asymmetric and repeated social dilemma game in which two actors can provide support for each other. We allow for asymmetry in three dimensions: (1) benefits from receiving support, (2) costs of providing support, and (3) the likelihood of needing support. Theoretically and empirically, we analyze the effects of asymmetry on the dynamics of support. We assume that the costs of providing and the benefits of receiving support as well as the likelihood of needing support affect an actors willingness to provide support. Using a behavioral game theory approach, we contribute to theory formation by developing a simple adaptive model for explaining behavior in support relations. More precisely, we offer two variants of such an adaptive model. One variant is inspired by social psychology and implements assumptions from equity theory. The other variant is inspired by bargaining theory and uses the Kalai-Smorodinsky bargaining solution. Our model is robust in the sense that both variants lead to similar predictions. Data from laboratory experiments confirm these predictions.