Why Trust Out-groups? The Role of Punishment Under Uncertainty

We conducted a hidden-effort trust game, in which we assigned subjects to one of two groups. The groups, which were formed through two different group formation processes, included a “social” group that required sharing and exchange among its members, and a “non-social” group that did not. Once assigned, subjects participated in the game with members from both groups, either with or without the opportunity to punish a trustee who may have defected on them. We found that for investors in the non-social group, the opportunity to punish a trustee worked to promote trust, but only when the trustee was a member of the other group. For the social group, the opportunity to punish had no effect on the investors’ trust decisions, regardless of the trustee\u27s group. We provide a theoretical framework to explain this asymmetric effect of punishment on trust. Our results suggest that groups with identities founded in sharing and exchange—a feature of globalized societies—may find it less necessary to engage in costly punishment. As a result, they may enjoy gains in economic efficiency

Politeness in Historical and Contemporary Chinese

Takes a comparative, diachronic perspective on Chinese politeness and its evolution up to the present day, linking diachronic and synchronic approache

Experiment on the Demand for Encompassment

The idea of political community is appealing on a gut-level. Hayek suggested that certain genes and instincts still dispose us toward the ethos and mentality of the hunter-gatherer band, and that modern forms of political collectivism have, in part, been atavistic reassertions of such tendencies. Picking up on Hayek, Klein (2005) has suggested a combination of yearnings: 1) a yearning for coordinated sentiment (like Smithian sympathy); and 2) a yearning that the sentiment encompass the whole group. This paper reports on an experiment designed to explore the demand for encompassment by having subjects sing together. In each trial, one person in the room was designated not to sing unless every one of the others in the room had made a payment sufficient so as to have that person sing. Subjects chose to sacrifice money to achieve encompassment 47.4 percent of the time, with 59.6 percent of the subjects doing so in at least one trial. An exit questionnaire showed that subjects’ chief reason for making such a sacrifice was a belief that the singing would be more enjoyable if it encompassed the whole group, and reported enjoyment is significantly higher with encompassment. We discuss the experiment as a parable for a penchant toward political collectivism.Encompassment; political psychology; Hayek; the people’s romance

Super-luminous X-ray Emission from the Interaction of Supernova Ejecta with Dense Circumstellar Shells

For supernova powered by the conversion of kinetic energy into radiation due to the interactions of the ejecta with a dense circumstellar shell, we show that there could be X-ray analogues of optically super-luminous SNe with comparable luminosities and energetics. We consider X-ray emission from the forward shock of SNe ejecta colliding into an optically-thin CSM shell, derive simple expressions for the X-ray luminosity as a function of the circumstellar shell characteristics, and discuss the different regimes in which the shock will be radiative or adiabatic, and whether the emission will be dominated by free-free radiation or line-cooling. We find that even with normal supernova explosion energies of 10^51 erg, there exists CSM shell configurations that can liberate a large fraction of the explosion energy in X-rays, producing unabsorbed X-ray luminosities approaching 10^44 erg/s events lasting a few months, or even 10^45 erg/s flashes lasting days. Although the large column density of the circumstellar shell can absorb most of the flux from the initial shock, the most luminous events produce hard X-rays that are less susceptible to photoelectric absorption, and can counteract such losses by completely ionizing the intervening material. Regardless, once the shock traverses the entire circumstellar shell, the full luminosity could be available to observers.Comment: Submitted to MNRAS. 12 pages, 4 figure

Personal Volunteer Computing

We propose personal volunteer computing, a novel paradigm to encourage technical solutions that leverage personal devices, such as smartphones and laptops, for personal applications that require significant computations, such as animation rendering and image processing. The paradigm requires no investment in additional hardware, relying instead on devices that are already owned by users and their community, and favours simple tools that can be implemented part-time by a single developer. We show that samples of personal devices of today are competitive with a top-of-the-line laptop from two years ago. We also propose new directions to extend the paradigm