Explicit vs. tacit collusion: the impact of communication in oligopoly experiments

publication-status: Acceptedtypes: ArticlePre-print draft published as working paper by Düsseldorf Institute for Competition Economics (DICE). NOTICE: this is the author’s version of a work that was accepted for publication in European Economic Review. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in European Economic Review, Elsevier, vol. 56(8), 2012, DOI: 10.1016/j.euroecorev.2012.09.002We explore the difference between explicit and tacit collusion by investigating the impact communication has in experimental markets. For Bertrand oligopolies with various numbers of firms, we compare pricing behavior with and without the possibility to communicate among firms. We find strong evidence that talking helps to obtain higher pro fits for any number of firms, however, the gain from communicating is nonmonotonic in the number of firms, with medium-sized industries having the largest additional profi t from talking. We also find that industries continue to collude successfully after communication is disabled. Communication supports firms in coordinating on collusive pricing schemes, and it is also used for conflict mediation.Financial support from Deutsche Forschungsgemeinschaft (DFG) is gratefully acknowledge

Where Two Are Fighting, the Third Wins: Stronger Selection Facilitates Greater Polymorphism in Traits Conferring Competition-Dispersal Tradeoffs

A major conundrum in evolution is that, despite natural selection, polymorphism is still omnipresent in nature: Numerous species exhibit multiple morphs, namely several abundant values of an important trait. Polymorphism is particularly prevalent in asymmetric traits, which are beneficial to their carrier in disruptive competitive interference but at the same time bear disadvantages in other aspects, such as greater mortality or lower fecundity. Here we focus on asymmetric traits in which a better competitor disperses fewer offspring in the absence of competition. We report a general pattern in which polymorphic populations emerge when disruptive selection increases: The stronger the selection, the greater the number of morphs that evolve. This pattern is general and is insensitive to the form of the fitness function. The pattern is somewhat counterintuitive since directional selection is excepted to sharpen the trait distribution and thereby reduce its diversity (but note that similar patterns were suggested in studies that demonstrated increased biodiversity as local selection increases in ecological communities). We explain the underlying mechanism in which stronger selection drives the population towards more competitive values of the trait, which in turn reduces the population density, thereby enabling lesser competitors to stably persist with reduced need to directly compete. Thus, we believe that the pattern is more general and may apply to asymmetric traits more broadly. This robust pattern suggests a comparative, unified explanation to a variety of polymorphic traits in nature.ope

The ‘mosaic habitat’ concept in human evolution: past and present

The habitats preferred by hominins and other species are an important theme in palaeoanthropology, and the ‘mosaic habitat’ (also referred to as habitat heterogeneity) has been a central concept in this regard for the last four decades. Here we explore the development of this concept – loosely defined as a range of different habitat types, such as woodlands, riverine forest and savannah within a limited spatial area– in studies of human evolution in the last sixty years or so. We outline the key developments that took place before and around the time when the term ‘mosaic’ came to wider palaeoanthropological attention. To achieve this we used an analysis of the published literature, a study of illustrations of hominin evolution from 1925 onwards and an email survey of senior researchers in palaeoanthropology and related fields. We found that the term mosaic starts to be applied in palaeoanthropological thinking during the 1970’s due to the work of a number of researchers, including Karl Butzer and Glynn Isaac , with the earliest usage we have found of ‘mosaic’ in specific reference to hominin habitats being by Adriaan Kortlandt (1972). While we observe a steady increase in the numbers of publications reporting mosaic palaeohabitats, in keeping with the growing interest and specialisation in various methods of palaeoenvironmental reconstruction, we also note that there is a lack of critical studies that define this habitat, or examine the temporal and spatial scales associated with it. The general consensus within the field is that the concept now requires more detailed definition and study to evaluate its role in human evolution

Absorption and mobility of foliar-applied boron in soybean as affected by plant boron status and application as a polyol complex

In the present study (i) the impact of plant Boron (B) status on foliar B absorption and (ii) the effect of B complexation with polyols (sorbitol or mannitol) on B absorption and translocation was investigated. Soybean (Glycine max (L.) Meer.) plants grown in nutrient solution containing 0 μM, 10 μM, 30 μM or 100 μM 11B labelled boric acid (BA) were treated with 50 mM 10B labelled BA applied to the basal parts of two leaflets of one leaf, either pure or in combination with 500 mM sorbitol or mannitol. After one week, 10B concentrations in different plant parts were determined. In B deficient leaves (0 μM 11B), 10B absorption was significantly lower than in all other treatments (9.7% of the applied dose vs. 26%–32%). The application of BA in combination with polyols increased absorption by 18–25% as compared to pure BA. The absolute amount of applied 10B moving out of the application zone was lowest in plants with 0 μM 11B supply (1.1% of the applied dose) and highest in those grown in 100 μM 11B (2.8%). The presence of sorbitol significantly decreased the share of mobile 10B in relation to the amount absorbed. The results suggest that 11B deficiency reduces the permeability of the leaf surface for BA. The addition of polyols may increase 10B absorption, but did not improve 10B distribution within the plant, which was even hindered when applied a sorbitol complex

Poverty in Asia and the Pacific: An Update

Poverty reduction in the Asia and the Pacific region in 2005–2008 had been quite significant. Despite the global crisis, an estimated 150 million people exited extreme poverty by 2008 - from 903.4 million in 2005 to 753.5 million, bringing the percentage of people living under the $1.25 per day poverty line to 21.9$1.25 and $2 per day poverty lines. This can be attributed to faster population growth than poverty reduction. The ranking of the large poor countries remained the same. In 2008, India continued as home to the largest number of the region's poor, followed by the PRC, Bangladesh, Indonesia, and Pakistan. While a significant number moved out of extreme poverty, the number of moderately poor - those living between$1.25 and $2 per day - dropped only marginally, by around 18.4 million. Using the$2 per day poverty line, 47.4% of the region's total population or 1.63 billion can be classified as poor in 2008. Fourteen of the 25 Asian Development Bank (ADB) developing member countries (DMCs) had headcount ratios above 40%. In particular, poverty reduction was slower in low-income DMCs than the others under both the $1.25 and$2 per day poverty lines, implying the need for continued financial support for poverty reduction. Due to the global crisis, poverty reduction became slower. Between 2008 and 2009, based on projections, the number of the poor is estimated to have increased in 9 and 10 of the 25 DMCs, under the $1.25 per day and$2 poverty lines, respectively. Asia and the Pacific region remains home to the largest number of the world's poor. In 2008, around 63% of the poor worldwide lived in the region

Between-Country Disparities in MDGs: The Asia and Pacific Region

This paper explores disparities in Millennium Development Goals among countries in the Asia and Pacific region, with a special emphasis on health Millennium Development Goals. It provides estimates on the extent of these disparities and depicts their trends. More importantly, sources or causes of the disparities are quantified and policy implications are discussed

Assessing the socioeconomic and infrastructure development disparity–a case study of city districts of Punjab, Pakistan

Socioeconomic and infrastructure development are the major sectors linked to prosperity of any region, while disparity in these sectors, in certain instances, hinder economic growth. This paper outlines an approach to examine development disparity in both spatial and temporal dimensions. A comparative analyses of socioeconomic and infrastructure development disparity among five city districts of Punjab province of Pakistan helped testing the proposed methods. The data variables and time periods (2002, 2007 and 2012) were selected based on the policy programmes introduced by the governments to reflect the closest factual position. Analyses revealed that development disparity prevailed, and the provincial capital (Lahore) remained the most developed. Moreover, the policy scrutiny indicate that despite the introduction of several national level policies and programmes, local Municipal Administrations have been incapable at handling the development issues. The proposed approach proved useful, and robust enough to be tested in a different regional setting.</p

Escaping from Poverty: Household Income Dynamics in Indonesia, South Africa, Spain, and Venezuela

[Excerpt] This study presents the main results of a larger, more technical report (Fields and others 2001) and subsequent work (Fields and others 2002) that analyzes income mobility in Indonesia, South Africa, Spain, and Venezuela. These economies were selected on the basis of the availability of panel data with which to analyze household income dynamics in the 1990s. By following households over time, we are able to investigate how households that were poor initially fared economically, relative to their richer counterparts. We can learn more about how and why households exit—and enter—poverty. To gauge income mobility, this study centers on the change in household per capita income over time, using two measures. Our first measure—a conventional one—gauges income changes in currency units. Our second measure, the change in log currency units, approximates the percentage changes in income. In this way, it arguably better reflects the reality of a poor household, in which a given change in income—whether an increase or a decrease—counts more than it does in a richer one.Fields9_Escaping_From_Poverty.pdf: 544 downloads, before Oct. 1, 2020

Does Income Mobility Equalize Longer-term Incomes? New Measures of an Old Concept

This paper develops a new class of measures of mobility as an equalizer of longer-term incomes – a concept different from other notions such as mobility as time-independence, positional movement, share movement, income flux, and directional income movement. A number of properties are specified leading to a class of indices, one easily-implementable member of which is applied to data for the United States and France. Using this index, income mobility is found to have equalized longer-term earnings among U.S. men in the 1970s but not in the 1980s or 1990s. In France, though, income mobility was equalizing throughout, and it has attained its maximum in the most recent period