Valuation Structure in First-Price and Least-Revenue Auctions: An Experimental Investigation

In many auctions the valuation structure involves both private and common value elements. Existing experimental evidence (e.g. Goeree and Offerman in Am. Econ. Rev. 92(3):625–643, 2002) demonstrates that first-price auctions with this valuation structure tend to be inefficient, and inexperienced subjects tend to bid above the break-even bidding threshold. In this paper, we compare first-price auctions with an alternative auction mechanism: the least-revenue auction. This auction mechanism shifts the risk regarding the common value of the good to the auctioneer. Such a shift is desirable when ex post negative payoffs for the winning bidder results in unfulfilled contracts, as is often the case in infrastructure concessions contracts. We directly compare these two auction formats within two valuation structures: (1) pure common value and (2) common value with a private cost. We find that, relative to first-price auctions, bidding above the break-even bidding threshold is significantly less prevalent in least-revenue auctions regardless of valuation structure. As a result, revenue in first-price auctions is higher than in least-revenue auctions, contrary to theory. Further, when there are private and common value components, least-revenue auctions are significantly more efficient than first-price auctions

Risk Preferences and Prenatal Exposure to Sex Hormones for Ladinos

Risk preferences drive much of human decision making including investment, career and health choices and many more. Thus, understanding the determinants of risk preferences refines our understanding of choice in a broad array of environments. We assess the relationship between risk preferences, prenatal exposure to sex hormones and gender for a sample of Ladinos, which is an ethnic group comprising 62.86% of the population of Guatemala. Prenatal exposure to sex hormones has organizational effects on brain development, and has been shown to partially explain risk preferences for Caucasians. We measure prenatal exposure to sex hormones using the ratio of the length of the index finger to the length of the ring finger (2D:4D), which is negatively (positively) correlated with prenatal exposure to testosterone (estrogen). We find that Ladino males are less risk averse than Ladino females, and that Ladino males have lower 2D:4D ratios than Ladino females on both hands. We find that the 2D:4D ratio does not explain risk preferences for Ladinos. This is true for both genders, and both hands. Our results highlight the importance of exploring the behavioral significance of 2D:4D in non-Caucasian racial groups

Discounting and digit ratio : Low 2D:4D predicts patience for a sample of females

Inter-temporal trade-offs are ubiquitous in human decision making. We study the relationship between preferences over such trade-offs and the ratio of the second digit to that of the forth (2D:4D), a marker for pre-natal exposure to sex hormones. Specifically, we study whether 2D:4D affects discounting. Our sample consists of 419 female participants of a Guatemalan conditional cash transfer program who take part in an experiment. Their choices in the convex time budget (CTB) experimental task allow us to make inferences regarding their patience (discounting), while controlling for present-biasedness and preference for smoothing consumption (utility curvature). We find that women with lower digit ratios tend to be more patient. © 2018 Aycinena and Rentschler

Learning Grammatical Models for Object Recognition

Many object recognition systems are limited by their inability to share common parts or structure among related object classes. This capability is desirable because it allows information about parts and relationships in one object class to be generalized to other classes for which it is relevant. With this goal in mind, we have designed a representation and recognition framework that captures structural variability and shared part structure within and among object classes. The framework uses probabilistic geometric grammars (PGGs) to represent object classes recursively in terms of their parts, thereby exploiting the hierarchical and substitutive structure inherent to many types of objects. To incorporate geometric and appearance information, we extend traditional probabilistic context-free grammars to represent distributions over the relative geometric characteristics of object parts as well as the appearance of primitive parts. We describe an efficient dynamic programming algorithm for object categorization and localization in images given a PGG model. We also develop an EM algorithm to estimate the parameters of a grammar structure from training data, and a search-based structure learning approach that finds a compact grammar to explain the image data while sharing substructure among classes. Finally, we describe a set of experiments that demonstrate empirically that the system provides a performance benefit

Discounting and Digit Ratio: Low 2D:4D Predicts Patience for a Sample of Females

Inter-temporal trade-offs are ubiquitous in human decision making. We study the relationship between preferences over such trade-offs and the ratio of the second digit to that of the forth (2D:4D), a marker for pre-natal exposure to sex hormones. Specifically, we study whether 2D:4D affects discounting. Our sample consists of 419 female participants of a Guatemalan conditional cash transfer program who take part in an experiment. Their choices in the convex time budget (CTB) experimental task allow us to make inferences regarding their patience (discounting), while controlling for present-biasedness and preference for smoothing consumption (utility curvature). We find that women with lower digit ratios tend to be more patient

Informed Entry in Auctions

We examine entry decisions in first-price and English clock auctions with participation costs. Potential bidders observe their value and report maximum willingness to pay (WTP) to participate. Entry occurs if revealed WTP (weakly) exceeds the randomly drawn participation cost. We find no difference in WTP between auction formats, although males have a higher WTP for first-price auctions. WTP is decreasing in the number of potential bidders, but this reduction is less than predicted and small in magnitude

Savings in Transnational Households: A Field Experiment Among Migrants from El Salvador

While remittance flows to developing countries are very large, it is unknown whether migrants desire more control over how remittances are used. This research uses a randomized field experiment to investigate the importance of migrant control over the use of remittances. In partnership with a Salvadoran bank, we offered US-based migrants from El Salvador bank accounts in their home country into which they could send remittances. We randomly varied migrant control over El Salvador-based savings by offering different types of accounts across treatment groups. Migrants offered the greatest degree of control over savings accumulated the most savings at the partner bank, compared to others offered less or no control over savings. Effects of this treatment on savings are concentrated among migrants who expressed demand for control over remittances in the baseline survey. We also find positive spillovers of our savings intervention in the form of increased savings at other banks (specifically, banks in the U.S.). We interpret the effects we find as arising from the joint effect of the bank account offers and the marketing pitch made to study participants by our project staff

Probabilistic geometric grammars for object recognition

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.Includes bibliographical references (p. 121-123).This thesis presents a generative three-dimensional (3D) representation and recognition framework for classes of objects. The framework uses probabilistic grammars to represent object classes recursively in terms of their parts, thereby exploiting the hierarchical and substitutive structure inherent to many types of objects. The framework models the 3) geometric characteristics of object parts using multivariate conditional Gaussians over dimensions, position, and rotation. I present algorithms for learning geometric models and rule probabilities given parsed 3D examples and a fixed grammar. I also present a parsing algorithm for classifying unlabeled, unparsed 3D examples given a geometric grammar. Finally, I describe the results of a set of experiments designed to investigate the chosen model representation of the framework.by Margaret Aida Aycinena.S.M

Social Norms and Dishonesty Across Societies

Social norms have long been recognized as an important factor in curtailing antisocial behavior, and stricter prosocial norms are commonly associated with increased prosocial behavior. In this study, we provide evidence that very strict prosocial norms can have a perverse negative relationship with prosocial behavior. In laboratory experiments conducted in 10 countries across 5 continents, we measured the level of honest behavior and elicited injunctive norms of honesty. We find that individuals who hold very strict norms (i.e., those who perceive a small lie to be as socially unacceptable as a large lie) are more likely to lie to the maximal extent possible. This finding is consistent with a simple behavioral rationale. If the perceived norm does not differentiate between the severity of a lie, lying to the full extent is optimal for a norm violator since it maximizes the financial gain, while the perceived costs of the norm violation are unchanged. We show that the relation between very strict prosocial norms and high levels of rule violations generalizes to civic norms related to common moral dilemmas, such as tax evasion, cheating on government benefits, and fare dodging on public transportation. Those with very strict attitudes toward civic norms are more likely to lie to the maximal extent possible. A similar relation holds across countries. Countries with a larger fraction of people with very strict attitudes toward civic norms have a higher society-level prevalence of rule violations