Identities, selection, and contributions in a public-goods game

The notions of one's social identity and group membership have recently become topics for economic theory and experiments, and recent research has shown the importance of identity in a wide array of economic environments. But predictions are unclear when there is some trade-off between one's identity (e.g., race, gender, handedness) and potential monetary considerations. We conduct a public-goods experiment in which we permit endogenous group-formation. In a 2x2 design, we vary whether people participate in a team-building exercise and whether some people receive an endowment twice as much as others receive. We find that when both identity and financial considerations are present, high-endowment participants are strongly attracted to each other, with one's word-task-group affiliation eclipsed by the opportunity to earn more. Nevertheless, the team-building exercise greatly increases the level of contribution whether or not one is linked to people from one's team-building exercise

Inequality aversion among Spanish gypsies: an experimental approach [Aversión a la desigualdad entre gitanos Españoles: un enfoque experimental]

This paper presents a first attempt to measure inequality aversion among gypsies. We conducted an experiment among adult gypsies living at slums outside Vallecas (Madrid). To analyze this variable we use the mechanism provided by Kroll & Davidovitz (2003) among 38 voluntary participants. Results indicate that: i) 52.6% of the individuals are inequality averse; ii) there is a positive relationship between inequality aversion and some features of the population such as individual religious practice, marital status, family size, position in the hierarchy of the family or club association and, iii) neither wealth, nor participation in voluntary activities affect inequality aversion

F stars, metallicity, and the ages of red galaxies at z > 1

We explore whether the rest-frame near-UV spectral region, observable in high-redshift galaxies via optical spectroscopy, contains sufficient information to allow the degeneracy between age and metallicity to be lifted. We do this by testing the ability of evolutionary synthesis models to reclaim the correct metallicity when fitted to the near-UV spectra of F stars of known (sub-solar and super-solar) metallicity. F stars are of particular interest because the rest-frame near-UV spectra of the oldest known elliptical galaxies at z > 1 appear to be dominated by F stars near to the main-sequence turnoff. We find that, in the case of the F stars, where the HST ultraviolet spectra have high signal:noise, model-fitting with metallicity allowed to vary as a free parameter is rather successful at deriving the correct metallicity. As a result, the estimated turnoff ages of these stars yielded by the model fitting are well constrained. Encouraged by this we have fitted these same variable- metallicity models to the deep, optical spectra of the z \simeq 1.5 mJy radio galaxies 53W091 and 53W069 obtained with the Keck telescope. While the age-metallicity degeneracy is not so easily lifted for these galaxies, we find that even when metallicity is allowed as a free parameter, the best estimates of their ages are still \geq 3 Gyr, with ages younger than 2 Gyr now strongly excluded. Furthermore, we find that a search of the entire parameter space of metallicity and star formation history using MOPED (Heavens et al., 2000) leads to the same conclusion. Our results therefore continue to argue strongly against an Einstein-de Sitter universe, and favour a lambda-dominated universe in which star formation in at least these particular elliptical galaxies was completed somewhere in the redshift range z = 3 - 5.Comment: 10 pages, LaTeX, uses MNRAS style file, incorporates 14 postscript figures, submitted to MNRAS. Changes include: inclusion of single stellar atmosphere model fits; more rigorous calculation of confidence regions; some re-structurin