Moral awareness polarizes people's fairness judgments.

How does moral awareness affect people's fairness judgments? Using a simple model of identity utility, I predict that if individuals differ in their personal fairness ideals (equality versus efficiency), reflecting over what one thinks is right should not only make people's choices less selfish but also more polarized. On the other hand, people's desire for conforming with the behavior of their peers could help mitigate polarization. I test these conjectures in a laboratory experiment, in which participants can pursue different fairness ideals. I exogenously vary (i) whether participants are prompted to state their moral opinions behind the veil of ignorance, and (ii) whether they are informed about the behavior of their peers. I find that moral introspection makes choices more polarized, reflecting even more divergent moral opinions. The increase in polarization coincides largely with a widening of revealed gender differences as introspection makes men's choices more efficiency-oriented and women's more egalitarian. Disclosing the descriptive norm of the situation is not capable of mitigating the polarization.

Echo chambers and opinion dynamics explain the occurrence of vaccination hesitancy.

Vaccination hesitancy is a major obstacle to achieving and maintaining herd immunity. Therefore, public health authorities need to understand the dynamics of an anti-vaccine opinion in the population. We introduce a spatially structured mathematical model of opinion dynamics with reinforcement. The model allows as an emergent property for the occurrence of echo chambers, i.e. opinion bubbles in which information that is incompatible with one's entrenched worldview, is probably disregarded. We scale the model both to a deterministic limit and to a weak-effects limit, and obtain bifurcations, phase transitions and the invariant measure. Fitting the model to measles and meningococci vaccination coverage across Germany, reveals that the emergence of echo chambers dynamics explains the occurrence and persistence of the anti-vaccination opinion in allowing anti-vaxxers to isolate and to ignore pro-vaccination facts. We predict and compare the effectiveness of different policies aimed at influencing opinion dynamics in order to increase vaccination uptake. According to our model, measures aiming at reducing the salience of partisan anti-vaccine information sources would have the largest effect on enhancing vaccination uptake. By contrast, measures aiming at reducing the reinforcement of vaccination deniers are predicted to have the smallest impact.

Internal conflict, market uniformity, and transparency in price competition between teams.

The way profits are divided within successful teams imposes different degrees of internal conflict. We experimentally examine how the level of internal conflict, and whether such conflict is transparent to other teams, affects teams' ability to compete vis-à-vis each other, and, consequently, market outcomes. Participants took part in a repeated Bertrand duopoly game between three-player teams which had either the same or different level of internal conflict (uniform vs. mixed). Profit division was either private-pay (high conflict; each member received her own asking price) or equal-pay (low conflict; profits were divided equally). We find that internal conflict leads to (tacit) coordination on high prices in uniform private-pay duopolies, but places private-pay teams at a competitive disadvantage in mixed duopolies. Competition is softened by transparency in uniform markets, but intensified in mixed markets. We propose an explanation of the results and discuss implications for managers and policy makers. (D43, L22, C92).