Safe options and gender differences in risk attitudes

Gender differences in risk attitudes have recently been shown to be context-dependent rather than ubiquitous. We manipulate three widely used risk elicitation tasks to test whether the presence of a safe option among the set of alternatives can explain the heterogeneity of the findings. We find that the availability of a safe option induces significant effects in two out of three tasks. Despite the well-known instability of elicited risk preferences, we show with a structural model that the effect on risk attitudes is rather stable across tasks, but not sufficiently strong to reach traditional significance levels

In and out of projects: a simple model and an experiment on the SourceForge development community

The allocation of time and effort within the communities of Open Source Software developers is an interesting yet relatively unexplored area. How can coordination be achieved, absent monetary rewards? How do developers choose where to direct their efforts amongst the thousands of existing software projects? How come the vast majority of Open Source projects is a failure, i.e. does not go beyond the announcement phase? The paper proposes a simple dynamic stochastic model that addresses these issues. The model is a non-strategic N-player dynamic interaction, in which players are asked to open, join or leave projects that are assigned a random probability of survival, a proxy for the project-launcher skills. The number and nature of open projects varying with time, players face a continuously chang- ing landscape. The model is simulated using a simple agent-based code, and tested in a lab with human subjects. Results show that the model can replicate most of the stylized facts of the SourceForge.net dataset, namely the high number of lurkers hopping from project to project and the highly skewed distribution. The experimental evidence supports the main behavioral hypothesis of the model, interestingly showing that human subject tend to consistently launch more projects than maximizing behavior would impl

Central tendency bias in belief elicitation

We conduct an experiment in which subjects participate in a first-price auction against an automaton that bids randomly in a given range. The subjects first place a bid in the auction. They are then given an incentivized elicitation of their beliefs of the opponent's bid. Despite having been told that the bid of the opponent is drawn from a uniform distribution, we find that a majority of subjects report beliefs that have a peak in the interior of the range. This result is robust across seven different experimental treatments. While not expected at the outset, these single-peaked beliefs have precedence in the experimental psychology judgments literature. Our results suggest that an elicitation of probability beliefs can result in responses that are more concentrated than the objectively known or induced truth. We provide indicative evidence that such individual belief reports can be rationalized by well-defined subjective beliefs that differ from the objective truth. Our findings offer an explanation for the conservatism and overprecision biases in Bayesian updating. Finally, our findings suggest that probabilistic forecasts of uncertain events might have less variance than the actual events

Elicitation of Preferences under Ambiguity

This paper is about behaviour under ambiguity ‒ that is, a situation in which probabilities either do not exist or are not known. Our objective is to find the most empirically valid of the increasingly large number of theories attempting to explain such behaviour. We use experimentally-generated data to compare and contrast the theories. The incentivised experimental task we employed was that of allocation: in a series of problems we gave the subjects an amount of money and asked them to allocate the money over three accounts, the payoffs to them being contingent on a ‘state of the world’ with the occurrence of the states being ambiguous. We reproduced ambiguity in the laboratory using a Bingo Blower. We fitted the most popular and apparently empirically valid preference functionals [Subjective Expected Utility (SEU), MaxMin Expected Utility (MEU) and α­-MEU], as well as Mean-Variance (MV) and a heuristic rule, Safety First (SF). We found that SEU fits better than MV and SF and only slightly worse than MEU and α­-MEU

Computational Cancer Biology: An Evolutionary Perspective

ISSN:1553-734XISSN:1553-735

Click‘n’Roll : No Evidence of Illusion of Control

Evidence of illusion of control\u2014the fact that people believe to have control over pure chance events\u2014is a recurrent finding in experimental psychology. Results in economics find instead little to no support. In this paper we test whether this dissonant result across disciplines is due to the fact that economists have implemented only one form of illusory control. We identify and separately tests in an incentive-compatible design two types of control: (a) over the resolution of uncertainty, as usually done in the economics literature, and (b) over the choice of the lottery, as sometimes done in the psychology literature but without monetary payoffs. Results show no evidence of illusion of control, neither on choices nor on beliefs about the likelihood of winning

Immersed boundary-finite element model of fluid-structure interaction in the aortic root

It has long been recognized that aortic root elasticity helps to ensure efficient aortic valve closure, but our understanding of the functional importance of the elasticity and geometry of the aortic root continues to evolve as increasingly detailed in vivo imaging data become available. Herein, we describe fluid-structure interaction models of the aortic root, including the aortic valve leaflets, the sinuses of Valsalva, the aortic annulus, and the sinotubular junction, that employ a version of Peskin's immersed boundary (IB) method with a finite element (FE) description of the structural elasticity. We develop both an idealized model of the root with three-fold symmetry of the aortic sinuses and valve leaflets, and a more realistic model that accounts for the differences in the sizes of the left, right, and noncoronary sinuses and corresponding valve cusps. As in earlier work, we use fiber-based models of the valve leaflets, but this study extends earlier IB models of the aortic root by employing incompressible hyperelastic models of the mechanics of the sinuses and ascending aorta using a constitutive law fit to experimental data from human aortic root tissue. In vivo pressure loading is accounted for by a backwards displacement method that determines the unloaded configurations of the root models. Our models yield realistic cardiac output at physiological pressures, with low transvalvular pressure differences during forward flow, minimal regurgitation during valve closure, and realistic pressure loads when the valve is closed during diastole. Further, results from high-resolution computations demonstrate that IB models of the aortic valve are able to produce essentially grid-converged dynamics at practical grid spacings for the high-Reynolds number flows of the aortic root

Morpho-Tectonic Evolution of the Southern Apennines and Calabrian Arc: Insights From Pollino Range and Surrounding Extensional Intermontane Basins

The evolution of topography in forearc regions results from the complex interplay of crustal and mantle processes. The Southern Apennines represent a well-studied forearc region that experienced several tectonic phases, initially marked by compressional deformation followed by extension and large-scale uplift. We present a new structural, geomorphic and fluvial analysis of the Pollino Massif and surrounding intermontane basins (Mercure, Campotenese and Castrovillari) to unravel their evolution since the Pliocene. We constrain multiple tectonic transport directions, evolution of the drainage, and magnitude and timing of long-term incision following base level falls. Two sets of knickpoints suggest two phases of base level lowering and allow to estimate similar to 500 m of long-term uplift (late Pleistocene), as observed in the Sila Massif. On a smaller spatial scale, the evolution and formation of topographic relief, sedimentation, and opening of intermontane basins is strongly controlled by the recent increase in rock uplift rate and fault activity. At the regional scale, an along-strike, long-wavelength uplift pattern from north to south can be explained by progressive lateral slab tearing and inflow of asthenospheric mantle beneath Pollino and Sila, which in turn may have promoted extensional tectonics. The lower uplift of Le Serre Massif may be explained as result of weak plate coupling due to narrowing of the Calabrian slab. The onset of uplift in the Pollino Massif, ranging from 400 to 800 ka, is consistent with that one proposed in the southern Calabrian forearc, suggesting a possible synchronism of uplift, and lateral tearing of the Calabrian slab.Topographic evolution constrained by structural, geomorphic and river analysis of the Pollino range and surrounding extensional basins At short spatial scale, increase in rock uplift and fault activity controls the endorheic-exorheic transition At regional scale, uplift increases between 400 and 800 ka, due to progressive lateral slab tearing, and inflow asthenospheric mantl

Tension sur l\u27édition scientifique - Croissance, modèles de business et points critiques (La)

Ce document aborde : L\u27Abondance de fonds pour la recherche • Open Access : plus de résultats disponibles à tous • Web: dissémination rapide • Moins d’articles qui restent dans les tiroirs • Plus de réplications, robustesse, méta-analyses... • Participation de chercheurs du Sud du mond