824 research outputs found
Heritability of Overconfidence
No full textEmpirical evidence suggests that people on average overestimate their own ability in a variety of circumstances. Little is known, however, about the origins of such overconfidence. To shed some light on this issue, we use the classic twin design to estimate the genetic and environmental contributions to individual differences in overconfidence. We collect data on overconfidence among 460 twin pairs. Overconfidence is measured as the difference between the perceived and actual rank in cognitive ability. Cognitive ability is measured using a 20-minute test of general intelligence. We find a highly significant joint effect of genes and common environment, but our estimates of the relative contributions of genetic and common environmental variation are less precise. According to our point estimates, genetic differences explain 16–34% of the variation in overconfidence depending on the definition of overconfidence used and common environmental differences explain 5–11%.Jan Wallander and Tom Hedelius FoundationSwedish Research CouncilSwedish Council forWorking Life and Social Researc
GENETIC VARIATION IN PREFERENCES FOR GIVING AND RISK TAKING
No full textIn this paper, we use the classical twin design to provide estimates of genetic
and environmental influences on experimentally elicited preferences for risk and
giving. Using standardmethods from behavior genetics, we find strong prima facie
evidence that these preferences are broadly heritable and our estimates suggest
that genetic differences explain approximately twenty percent of individual variation.
The results thus shed light on an important source of individual variation
in preferences, a source that has hitherto been largely neglected in the economics
literature.Swedish Research CouncilForskningsrådet för arbetsliv och socialvetenskap (Sweden)Jan Wallander and Tom Hedelius Foundatio
No Association between Oxytocin Receptor (OXTR) Gene Polymorphisms and Experimentally Elicited Social Preferences
No full textBackground
Oxytocin (OXT) has been implicated in a suite of complex social behaviors including observed choices in economic laboratory experiments. However, actual studies of associations between oxytocin receptor (OXTR) gene variants and experimentally elicited social preferences are rare.
Methodology/Principal Findings
We test hypotheses of associations between social preferences, as measured by behavior in two economic games, and 9 single nucleotide polymorphisms (SNPs) of the OXTR gene in a sample of Swedish twins (n = 684). Two standard economic games, the dictator game and the trust game, both involving real monetary consequences, were used to elicit such preferences. After correction for multiple hypothesis testing, we found no significant associations between any of the 9 single nucleotide polymorphisms (SNPs) and behavior in either of the games.
Conclusion
We were unable to replicate the most significant association reported in previous research between the amount donated in a dictator game and an OXTR genetic variant
Essays on genetic variation and economic behavior
No full textThesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Economics, 2010.Cataloged from PDF version of thesis.Includes bibliographical references.This thesis is a collection of papers in which behavior genetic methods are used to shed light on individual differences in economic preferences, behaviors and outcomes. Chapter one uses the classical twin design to provide estimates of genetic and environmental influences on experimentally elicited preferences for risk and giving. The paper reports evidence that these preferences are broadly heritable, with estimates suggesting that genetic differences explain approximately twenty percent of individual variation. The results thus point to genes as an important source of individual variation in preferences, a source which has hitherto been largely neglected in the economics literature. The chapter is written with Christopher T. Dawes, Magnus Johannesson, Paul Lichtenstein and Bjorn Wallace. Chapter two shows that these findings also extend to the field. Following a major pension reform in the late 1990s, all Swedish adults had to form a portfolio from a large menu of funds. Matching individual investment decisions to the Swedish Twin Registry, the paper finds that approximately 25% of individual variation in portfolio risk is due to genetic variation. The results, which are complementary to those reported in chapter one, also hold for several other aspects of financial decision-making. The chapter is written with Magnus Johannesson, Paul Lichtenstein, Orjan Sandewall and Bjorn Wallace. Chapter three uses two complementary Swedish datasets to examine the importance of family environment in explaining variation in income, educational attainment, and measures of cognitive and non-cognitive skills. Using seven different sibling types who differ in their degree of genetic relatedness and rearing status, I find moderate family effects on educational attainment, cognitive skills and non-cognitive skills. This contrasts with the effects of family on income, which are low. Additional analyses, based on a sample of identical (MZ) and fraternal (DZ) twins for which more comprehensive income data is available, reveal large and persistent separation of the MZ and DZ correlations over the entire lifecycle, except at very early ages. One interpretation of this finding is that there are strong family effects on the timing of labor market entry. I discuss the relevance of these results for efforts to understand the causes of income inequality.by David Alexander Cesarini.Ph.D
GraphDBLP: a system for analysing networks of computer scientists through graph databases
No full textThis paper presents GraphDBLP, a system that models the DBLP bibliography as a graph database for performing graph-based queries and social network analyses. GraphDBLP also enriches the DBLP data through semantic keyword similarities computed via word-embedding. In this paper, we discuss how the system was formalized as a multi-graph, and how similarity relations were identified through word2vec. We also provide three meaningful queries for exploring the DBLP community to (i) investigate author profiles by analysing their publication records; (ii) identify the most prolific authors on a given topic, and (iii) perform social network analyses over the whole community. To date, GraphDBLP contains 5+ million nodes and 24+ million relationships, enabling users to explore the DBLP data by referencing more than 3.3 million publications, 1.7 million authors, and more than 5 thousand publication venues. Through the use of word-embedding, more than 7.5 thousand keywords and related similarity values were collected. GraphDBLP was implemented on top of the Neo4j graph database. The whole dataset and the source code are publicly available to foster the improvement of GraphDBLP in the whole computer science community
Trichoderma strain-dependent direct and indirect biocontrol of Fusarium head blight caused by Fusarium graminearum in wheat
No full textFusarium head blight (FHB), caused by Fusarium graminearum (Fg), is a major disease of wheat not only due to crop yield losses but also because of food safety concerns, since Fg produces toxic trichotecenes, such as deoxynivalenol (DON). Different Trichoderma strains have shown biocontrol efficacy against various Fusarium spp. in a wide variety of pathosystems. In this work, the efficacy of T. asperellum T25, T. harzianum T136 and T. simmonsii T137, was assessed against Fg ITEM 124 in in vitro tests, which included dual cultures, as well as cellulose and cellophane membrane assays. The three Trichoderma strains inhibited Fg growth to varying degrees. However, only T25 and T136 demonstrated control of FHB in wheat when applied to spikes. By quantitative real-time PCR (qPCR) we analysed the expression of eight plant defence-related marker genes in wheat spikes inoculated with Trichoderma, or not, and subsequently infected with Fg. Only wheat spikes pre-treated with T25 or T136 look to activate the salicylic acid-dependent defence, in response to pathogen infection. Expression of tri genes, involved in DON biosynthesis, was analysed by qPCR in dual-culture Trichoderma-Fg confrontations in two different media, and in the plant spikes. Confrontation results indicated that tri gene expression depends on the Trichoderma strain and the culture medium, but the three Trichoderma strains reduced the expression of tri5 in the plant. Results show that T. asperellum T25 reduced FHB disease index by more than 60 %, and was the most effective biocontrol agent, employing direct mechanisms to limit Fg growth and indirect mechanisms by priming local plant defences
Exploring the synergistic potential of Trichoderma gamsii T6085 and Clonostachys rosea IK726 for biological control of Fusarium head blight in wheat
No full textWe explore the combined use of two beneficial fungal isolates, Trichoderma gamsii T6085 (Tg) and Clonostachys rosea IK726 (Cr), to enhance Fusarium head blight (FHB) management by biological control. We found no evidence for mycoparasitism or inhibition via diffusible metabolites, but Tg volatiles inhibited Cr growth slightly. Although Cr reduced Tg spore germination and mycelial growth in liquid culture, this effect seemed absent in planta. The BCAs differently modulated defence-related (DR) genes when colonizing roots or spikes. At seven days post-inoculation (dpi), root-applied Cr, alone and co-inoculated, induced a minor upregulation of PR1. In leaves, a systemic signalling response by root inoculation was detected. In spikes, Pal1, PR1, and Lox1 were upregulated by Cr alone and co-inoculated at 96 hours post-inoculation (hpi). However, Lox1 activation was enhanced by co-inoculation. On spikes inoculated with Fg, the BCAs revealed different patterns of DR gene modulation indicating involvement of different biocontrol mechanisms. In detail, Pgip2 was primarily upregulated at 24 hpi in co-inoculated spikes whereas at 72 hpi activation of DR genes was observed only with Tg. Notably, the disease incidence was reduced by 93 % by co-inoculation. In addition, the inoculum potential of F. graminearum on straw was reduced by all BCAs treatments, with ≥ 96 % reduction of perithecia after six months incubation. Our results show the potential of combining Tg and Cr as a more effective and stable FHB management strategy, than by treatments with the individual strains
GraphDBLP Released: Querying the Computer Scientists Network as a Graph
No full textIn this paper we introduce GraphDBLP, a tool that models the DBLP bibliography as a graph, and enriches the DBLP data through semantic keyword similarities computed via word-embedding. GraphDBLP has been implemented on top of the Neo4j graph-database, and it can be queried through the Cypher query language. We also provide three meaningful queries for exploring the DBLP community to (i) investigate author profiles by analysing their publication records; (ii) identify the most prolific authors on a given topic,and (iii) perform social network analyses over the whole community. GraphDBLP is available on Github. To date, it contains 5+ million nodes and 24+ million relationships, enabling users to explore the DBLP data by referencing more than 3.3 million publications, 1.7 million authors and more than 5 thousand publication venues. Thanks to the use of word-embedding, more than 7.5 thousand keywords and related similarity values were collected
Are Attitudes Towards Economic Risk Heritable? Analyses Using the Australian Twin Study of Gambling
No full textThis study employs multiple regression models based on DeFries and Fulker (1985), and a large sample of twins, to assess heritability in attitudes towards economic risk, and the extent to which this heritability differs between males and females. Consistent with Cesarini, Dawes, Johannesson, Lichtenstein and Wallace (2009), it is found that attitudes towards risk are moderately heritable, with about 20 percent of the variation in these attitudes across individuals being linked to genetic differences. This value is less than one-half the estimates reported by Zyphur, Narayanan, Arvey and Alexander (2009) and Zhong, Chew, Set, Zhang, Xue, Sham, Ebstein and Israel (2009). While females are more risk averse than males, there is no evidence that heritability in attitudes towards risk differs between males and females. Even though heritability is shown to be important to economic risk taking, the analyses suggest that multivariate studies of the determinants of attitudes towards risk which to not take heritability into consideration still provide reliable estimates of the partial effects of other key variables, such as gender and educational attainment.risk, heritability, gender
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