Trust, Communication and Contracts: An Experiment

In the one-shot trust or investment game without opportunities for reputation formation or contracting, economic theory predicts no trusting because there is no incentive for trustworthiness. Under these conditions, theory predicts (a) no effect of pre-play communication, and (b) universal preference for moderate cost binding contracts over interacting without contracts. We introduce the opportunities to engage in pre-play communication and to enter binding or non-binding contracts, and find (a) communication increases trusting and trustworthiness, (b) contracts are largely unnecessary for trusting and trustworthy behaviors and are eschewed by many players, and (c) more trusting leads to higher earnings, and (d) both trustors and trustees favor “fair and efficient” proposals over the more unequal proposals predicted by theory.trust game, trust, trustworthiness, reciprocity, commitment, communication. Comparative analysis of agency problems, Production of public goods

Lavish Returns on Cheap Talk: Non-binding Communication in a Trust Experiment

We let subjects interact with anonymous partners in trust (investment) games with and without one of two kinds of pre-play communication: numerical (tabular) only, and verbal and numerical. We find that either kind of pre-play communication increases trusting, trustworthiness, or both, in inter-subject comparisons, but that the inclusions of verbal communication generates both a larger effect and one that is robust across both inter-subject and intra-subject comparisons. In all conditions, trustors earn more when they invest more of their endowment, trustors and trustees gravitate to "fair and efficient" interactions, and the majority of trustees adhere to their commitments, whether explicit or implicit. Finally, we study trusting and trustworthiness in the sense of adhering to agreements, and we find that both are enhanced when the parties can use words, and especially when an agreement is reached with words and not only with the exchange of numerical proposals.

Reciprocity in a Two-Part Dictator Game

We conduct a dictator game experiment in which recipients in an initial game become dictators in a second game. When the subjects paired remain the same, the amount sent back is strongly correlated with the amount received, despite the fact that the interaction is anonymous and is known to be one-time and zero-sum in nature. When the initial recipient is instead paired with a third subject, a less significant and lower-valued correlation between amounts received and sent is exhibited. Intelligence and personality test results, gender, and other characteristics also help to predict sending behavior and degree of reciprocity.reciprocity, dictator game, cognition, personality, altruism

Valores e instituciones en el análisis económico

The economic science, the so-called ‘neoclassical economics’, has usually avoided considering the values of its field of study. This has led to important limitations in its theoretical system. This article intends to go beyond this neutral positivist approach. It presents different theoretical lines which include those values within the economic analysis, exploring their consequences. It studies the relationship between values and the individuals’ behaviour, specially the cooperative behaviour, and the relationship between values and institutions and organizations. (Editor’s note: cooperatives are organizations which have historically included certain social values, such as democracy, equity and solidarity, among their rules of economic behaviour).Values, institution, organization, economic analysis, cooperation, game theory, experimental economy.

The first super-Earth Detection from the High Cadence and High Radial Velocity Precision Dharma Planet Survey

The Dharma Planet Survey (DPS) aims to monitor about 150 nearby very bright FGKM dwarfs (within 50 pc) during 2016$-$2020 for low-mass planet detection and characterization using the TOU very high resolution optical spectrograph (R$\approx$100,000, 380-900nm). TOU was initially mounted to the 2-m Automatic Spectroscopic Telescope at Fairborn Observatory in 2013-2015 to conduct a pilot survey, then moved to the dedicated 50-inch automatic telescope on Mt. Lemmon in 2016 to launch the survey. Here we report the first planet detection from DPS, a super-Earth candidate orbiting a bright K dwarf star, HD 26965. It is the second brightest star ($V=4.4$ mag) on the sky with a super-Earth candidate. The planet candidate has a mass of 8.47$\pm0.47M_{\rm Earth}$, period of $42.38\pm0.01$ d, and eccentricity of $0.04^{+0.05}_{-0.03}$. This RV signal was independently detected by Diaz et al. (2018), but they could not confirm if the signal is from a planet or from stellar activity. The orbital period of the planet is close to the rotation period of the star (39$-$44.5 d) measured from stellar activity indicators. Our high precision photometric campaign and line bisector analysis of this star do not find any significant variations at the orbital period. Stellar RV jitters modeled from star spots and convection inhibition are also not strong enough to explain the RV signal detected. After further comparing RV data from the star's active magnetic phase and quiet magnetic phase, we conclude that the RV signal is due to planetary-reflex motion and not stellar activity.Comment: 13 pages, 17 figures, Accepted for publication in MNRA

The first super-Earth detection from the high cadence and high radial velocity precision Dharma Planet Survey

The Dharma Planet Survey (DPS) aims to monitor about 150 nearby very bright FGKM dwarfs (within 50 pc) during 2016–2020 for low-mass planet detection and characterization using the TOU very high resolution optical spectrograph (⁠R≈100000⁠, 380–900 nm). TOU was initially mounted to the 2-m Automatic Spectroscopic Telescope at Fairborn Observatory in 2013–2015 to conduct a pilot survey, then moved to the dedicated 50-inch automatic telescope on Mt. Lemmon in 2016 to launch the survey. Here, we report the first planet detection from DPS, a super-Earth candidate orbiting a bright K dwarf star, HD 26965. It is the second brightest star (V = 4.4 mag) on the sky with a super-Earth candidate. The planet candidate has a mass of 8.47 ± 0.47MEarth, period of 42.38 ± 0.01 d, and eccentricity of 0.04+0.05−0.03⁠. This radial velocity (RV) signal was independently detected by Díaz et al., but they could not confirm if the signal is from a planet or stellar activity. The orbital period of the planet is close to the rotation period of the star (39–44.5 d) measured from stellar activity indicators. Our high precision photometric campaign and line bisector analysis of this star do not find any significant variations at the orbital period. Stellar RV jitters modelled from star-spots and convection inhibition are also not strong enough to explain the RV signal detected. After further comparing RV data from the star’s active magnetic phase and quiet magnetic phase, we conclude that the RV signal is due to planetary-reflex motion and not stellar activity

Indirect Effects of Ploidy Suggest X Chromosome Dose, Not the X:A Ratio, Signals Sex in Drosophila

In the textbook view, the ratio of X chromosomes to autosome sets, X:A, is the primary signal specifying sexual fate in Drosophila. An alternative idea is that X chromosome number signals sex through the direct actions of several X-encoded signal element (XSE) proteins. In this alternative, the influence of autosome dose on X chromosome counting is largely indirect. Haploids (1X;1A), which possess the male number of X chromosomes but the female X:A of 1.0, and triploid intersexes (XX;AAA), which possess a female dose of two X chromosomes and the ambiguous X:A ratio of 0.67, represent critical tests of these hypotheses. To directly address the effects of ploidy in primary sex determination, we compared the responses of the signal target, the female-specific SxlPe promoter of the switch gene Sex-lethal, in haploid, diploid, and triploid embryos. We found that haploids activate SxlPe because an extra precellular nuclear division elevates total X chromosome numbers and XSE levels beyond those in diploid males. Conversely, triploid embryos cellularize one cycle earlier than diploids, causing premature cessation of SxlPe expression. This prevents XX;AAA embryos from fully engaging the autoregulatory mechanism that maintains subsequent Sxl expression, causing them to develop as sexual mosaics. We conclude that the X:A ratio predicts sexual fate, but does not actively specify it. Instead, the instructive X chromosome signal is more appropriately seen as collective XSE dose in the early embryo. Our findings reiterate that correlations between X:A ratios and cell fates in other organisms need not implicate the value of the ratio as an active signal