Levente Littvay

HUN-REN Centre for Social Sciences · Institute for Political Science

There is a growing worry about the health of American democracy, and political scientists and pundits alike are looking for possible explanations. Surveys conducted during the Trump presidency showed considerable citizen support for liberal democratic norm erosions, especially among Republicans. However, recent experimental research also shows that...

This paper introduces "Chrono-sampling," a novel method leveraging Large Language Models (LLMs) to simulate historical survey respondents, enabling social science researchers to explore past public opinions as if they had access to a "time machine." The study builds on recent advancements in generative AI, particularly LLMs like OpenAI's GPT, which...

Between 2006 and 2021, the Hungarian Twin Registry (HTR) operated a volunteer twin registry of all age groups (50% monozygotic [MZ], 50% dizygotic [DZ], 70% female, average age 34 ± 22 years), including 1044 twin pairs, 24 triplets and one quadruplet set. In 2021, the HTR transformed from a volunteer registry into a population-based one, and it was...

There is a growing worry about the health of American democracy and politicalscientists and pundits alike are looking for possible explanations. Surveys conducted during the Trump presidency showed considerable citizen support for liberal democratic norm erosions, especially among Republicans. However, recent experimental research also shows that v...

Previous research documents the relationship between negative treatments of outgroup members and moral exclusion. In this study, we expect negative treatments of the ingroup members to be also related to a moral exclusionary mechanism. Next, we hypothesize that the relationship between intragroup moral exclusion and behavioral intentions (both posi...

This study evaluates parental grit’s covariation with offspring grit and the moderating role of different parenting behaviors using an 11-country study of young adults between the ages of 18 and 35 (n = 20,008) and their parents (n = 5945). Results show that parental grit is associated with offspring’s grit with moderation of parenting present acro...

Background Genetics have a strong influence on calcified atherosclerotic plaques; however, data regarding the heritability of noncalcified plaque volume are scarce. We aimed to evaluate genetic versus environmental influences on calcium (coronary artery calcification) score, noncalcified and calcified plaque volumes by coronary computed tomography...

The Hungarian municipal elections of October 2019 were the first ray of hope for the numerous political forces aiming to topple the decade-long Fidesz rule. In this election, the opposition won Budapest’s mayoral seat and 10 of the 23 larger cities (turning 8). They also won majorities in the capital’s assembly and among the 23 district mayors (tur...

Until recently, explanations of the origins of social traits relied nearly exclusively on the environment. While early evidence in favor of biologically based accounts received mixed reactions and were slow to gain traction in the social sciences, the 2005 breakthrough study of John Alford and colleagues was followed by an explosion of studies look...

This short report describes the development of a COVID-19 module for Round 10 of the European Social Survey (ESS). The module is formed of 20 items, including 10 agreed with ESS National Coordinators and 10 developed by two academic teams following an external call for content. The majority of ESS participating countries will field the module for R...

While several contemporary explanations for the electoral success of populist parties include the impact of populist attitudes by voters, the mechanism through which those attitudes turn into voting behavior remains elusive. One theoretical proposition (Hawkins et al. 2018) is the “activation theory”, according to which voters’ populist attitudes l...

Objectives of the study: Nonalcoholic fatty liver disease (NAFLD) is a common condition with a subset of individuals developing liver fibrosis as a major risk factor for advanced liver disease. The contribution of genetic factors to this progression remains incompletely understood. Our aim was to analyze heritability in the development of liver fi...

Studies of demand-side populism with a focus on attitudinal and behavioral factors are becoming more popular, but only a few have explored the phenomenon's psychological determinants. We tackle the lack of conversation between populism scholars and political psychologists and test the impact of conspiracy beliefs, moral disengagement, need for cogn...

In the last decade, political protest events have been rising in Western democracies. At the same time, there has been a steady increase in the diffusion of conspiracy theories in political communication, a phenomenon that has captured the interest of scholars for its growing political relevance. However, while most research focuses on the reasons...

Aims Left atrial (LA) remodelling is a common feature of many cardiovascular pathologies and is a sensitive marker of adverse cardiovascular outcomes. The aim of this study was to establish normal ranges for LA parameters derived from coronary computed tomographic angiography (CCTA) imaging using a standardised image processing pipeline to establis...

Citizen support for democracy-eroding political leaders is receiving much overdue attention, but existing studies have a difficulty disentangling contextual effects (such as who is in power at the time of the survey) from individual differences (like which party one supports and how much). We propose a novel survey experimental design to strip away...

With a decade of democratic backsliding in the world and the polarization-driven institutional erosion in the US, people's support for democracy-eroding political leaders is receiving much overdue attention. But existing studies have a difficulty disentangling contextual effects (such as who is in power at the time of the survey) from individual di...

With a decade of democratic backsliding in the world and the polarization-driven institutional erosion in the US, people's support for democracy-eroding political leaders is receiving much overdue attention. But existing studies have a difficulty disentangling contextual effects (such as who is in power at the time of the survey) from individual di...

In the last decade, political protest events have been rising in Western democracies. At the same time, there has been a steady increase in the diffusion of conspiracy theories in political communication, a phenomenon that has captured the interest of scholars for its growing political relevance. However, while most research focuses on the reasons...

Az ikerkutatás mint a genetikai tudományok egyik speciális területe napjainkban virágkorát éli szerte a világon, ugyanakkor a hazai egyetemi oktatásban szinte minimális ismereteket kap a hallgató e témakörben. Ennek a hiánynak a felismerése késztette arra a könyv szerkesztőit, hogy a szakma legautentikusabb képviselőinek bevonásával egy olyan össz...

Since our last report on the voluntary Hungarian Twin Registry (HTR) in 2012, the number of pairs or multiplets included increased from 310 to 1044. Efforts to turn the registry into a population-based one are on the way. Nearly 128,000 twins living in Hungary (98,500 adults) will be mailed information on how to register on the new HTR website. Twi...

Representation failures are one of the main reasons for the emergence of populism in contemporary politics. Mainstream parties’ convergence towards the centre left parts of the electorate to feel underrepresented. Populists are successful when they engage apathetic voters. In this sense, populism is suggested to be a potential corrective to democra...

This handbook is currently in development, with individual articles publishing online in advance of print publication. At this time, we cannot add information about unpublished articles in this handbook, however the table of contents will continue to grow as additional articles pass through the review process and are added to the site. Please note...

Expert evaluations about countries form the backbone of comparative political research. It is reasonable to assume that such respondents, no matter the region they specialize in, will have a comparable understanding of the phenomena tapped by expert surveys. This is necessary to get results that can be compared across countries, which is the fundam...

With the victory of Donald Trump in the 2016 United States presidential election, populists have come to power in the US for the first time in many years. However, US political scientists have been flat-footed in their response, failing to anticipate or measure populism's impact on the campaign or to offer useful policy responses. In contrast, popu...

Introduction: Recent experimental and population studies have highlighted the existence of telomere-mitochondria interplay. Besides studies revealing the molecular mechanisms underlying the associations of telomere defects and mitochondrial functions, investigations of mitochondrial DNA copy number (mtDNAcn) and telomere length (TL) in healthy and...

With the recent upsurge of populism in developed and transition democracies, researchers have started measuring it as an attitude. Several scales have been proposed for this purpose. However, there is little direct comparison between the available alternatives. Scholars who wish to measure populist attitudes have little information available to hel...

After online first publication of the article, it was noticed that the family name of author Panos Tsakloglou was erroneously misspelt as Tsakoglou.

Background: Anatomic variants of the circle of Willis (CW) are commonly observed in healthy subjects. Genetic and environmental factors influencing these variants remain unclear. Our aim was to assess the genetic and environmental background affecting variant CW phenotypes. Methods: A total of 122 adult healthy twins from the Hungarian Twin Regi...

Existing datasets provided by statistical agencies (e.g. Eurostat) show that the economic and financial crisis that unfolded in 2008 significantly impacted the lives and livelihoods of young people across Europe. Taking these official statistics as a starting point, the collaborative research project “Cultural Pathways to Economic Self-Sufficiency...

Morphological and hemodynamic variations of the circle of Willis (CW) may have an important impact on cerebrovascular events. However, the environmental and genetic influence remains unclear. For this reason we studied the variations and hemodynamic parameters of the CW in twins using transcranial color-coded sonography (TCCS). Sixty-four twins, 19...

Our study analyzed lymphocyte subpopulations of 32 monozygotic twins and compared the level of the catalytic reverse transcriptase protein subunit (hTERT) in T lymphocytes (Tly), helper- (Th), cytotoxic- (Tc) and regulatory T cell (Treg) subgroups. Four variables related to telomere and mitochondrial biology were simultaneously assessed, applying m...

Background: We aimed at evaluating the impact of genetic and environmental factors on longitudinal changes in aortic pulse wave velocity (aPWV) and aortic augmentation index (aAIx). Method: Three hundred and sixty-eight Italian and Hungarian adult twins (214 monozygotic, 154 dizygotic) underwent repeated evaluations of aPWV and aAIx (TensioMed A...

POLICY BRIEF ON POPULISM IN EUROPE AND THE AMERICAS: WHAT, WHEN, WHO, AND SO WHAT?

[This corrects the article DOI: 10.1371/journal.pone.0192948.].

Aims The elasticity of the internal jugular vein (IJV) is a major determinant of cerebral venous drainage and right atrium venous return. However, the level of genetic determination of IJV dimensions, compliance and distensibility has not been studied yet. Methods 170 adult Caucasian twins (43 monozygotic [MZ] and 42 dizygotic [DZ] pairs) were inv...

Diameters of the inner jugular vein measured ultrasonographically. Original data measured on twins. Anonimous Italian twin registry codes are shown. F, female, M, male, MZ, monozygotic, DZ, dizygotic twin pairs. Sit, sitting, Sup, supine body positions. Vals, during 60 mmHg Valsalva test, no Vals, without it with normal breathing. MLD, mediolateral...

This observational study intends to estimate the causal effects of an English as a Medium of Instruction (EMI) program (as predictor) on students Grade Point Average (GPA) (as outcome) at a particular University in Spain by using a Counterfactual Impact Evaluation (CIE). The need to address the crucial question of causal inferences in EMI programs...

In recent years, scholars have started to measure and explain populism at the micro-level, as an attitude that individuals hold about politics. Multiple scales have been proposed but, as the overview by Van Hauwaert et al. indicates, they all have limitations. Most do not capture a broad range of the phenomenon – being able to discriminate only amo...

Studies of political attitudes and ideologies have sought to explain their origin. They have been assumed to be a result of political values ingrained during the process of socialization until early adulthood, as well as personal political experience, party affiliation, social strata, etc. As a consequence of these environment-dominated explanation...

We explore the relationship between populist attitudes and conspiratorial beliefs on the individual level with two studies using American samples. First, we test whether and what kinds of conspiratorial beliefs predict populist attitudes. Our results show that belief in conspiracies with greedy, but not necessarily purely evil, elites are associate...

Prior behavioral genetic studies in positive psychology were entirely based on data from Western democracies, leaving the question open whether the magnitude of genetic effects on well-being indicators is similar in substantially different societal contexts. The aim of this study, therefore, was to investigate the structure of the genetic and envir...

Background and purpose: In contrast with the carotid arteries, the vertebral arteries (VAs) show considerable variation in length, caliber, and vessel course. This study investigated whether the variation in diameter and flow characteristics of the VAs might be inherited. Methods: A total of 172 Italian twins from Padua, Perugia, and Terni (54 m...

Background: The measurement of femoral intima-media thickness (IMT) is underutilized in the clinical practice, although it is a surrogate marker of cardiovascular disease. Materials and methods: 388 Hungarian and Italian twins (121 monozygotic, 73 dizygotic pairs) underwent bilateral B-mode sonography of femoral arteries. IMT was measured by sem...

Doppler interrogation studies of the liver blood flow indicate altered hepatic vein waveforms in association with impaired hepatocellular function. However, little is known about the mechanisms responsible for variations of these parameters in the absence of disease. We aimed to investigate the contribution of heritable and environmental factors to...

Background: Although it is known that some corneal diseases and degenerations have a significant heritable background, heritability on corneal endothelial cell density (ECD) has never been clearly determined. Our aim was to determine the heritability of corneal ECD. Material and methods: Corneal ECD of 114 eyes (66 eyes of 33 monozygotic and 48...

Objectives: We aimed to assess heritable and environmental effects on the abdominal aortic diameter. Methods: 114 adult (69 monozygotic, 45 same-sex dizygotic) twin pairs (mean age 43.6 ± 16.3 years) underwent abdominal ultrasound with Esaote MyLab 70X ultrasound machine to visualize the abdominal aorta below the level of the origin of the renal...

The heritability of coronary atherosclerotic plaque burden, coronary geometry, and phenotypes associated with increased cardiometabolic risk are largely unknown. The primary aim of the Burden of Atherosclerotic Plaques Study in Twins-Genetic Loci and the Burden of Atherosclerotic Lesions (BUDAPEST-GLOBAL) study is to evaluate the influence of genet...

Objectives Decreased thyroid volume has been related to increased prevalence of thyroid cancer. Subjects and methods One hundred and fourteen Hungarian adult twin pairs (69 monozygotic, 45 dizygotic) with or without known thyroid disorders underwent thyroid ultrasound. Thickness of the thyroid isthmus was measured at the thickest portion of the gl...

In this study, we discuss one example where behavior genetic findings vary greatly across political contexts. We present original findings on how party identification is heritable around the 2008 election on a sample of twins from Minnesota. As this is in contrast with findings from the late 1980s and with how a mid-2000 study interpreted their res...

Arterial stiffness, an independent predictor of cardiovascular disease has been associated with the presence and extent of coronary artery calcification (CAC). We sought to assess the relationship between various hemodynamic parameters and presence of coronary atherosclerotic plaques. In a prospective study 213 subjects (76 men and 137 women, mean...

Cerebrovascular resistance is a pressure-dependent mechanism resulting from cerebral autoregulation, which is the normal buffering of changes in arterial blood pressure. Lifestyle habits are known to have an influence; however, its magnitude is still unclear. The aim of this study was to assess the contribution of additive genetic, shared and unsha...

Introduction and objective: The role of genetic factors in nicotine dependence is well understood, but no information is available on the inheritability of second-hand smoke (SHS) exposure sensitivity and their co-variance. Materials and methods: 186 adult same-gender pairs of twin (146 monozygotic, 40 dizygotic; 44±17 years±SD) completed a ques...

Background Ultrasound measurements of renal dimensions are conventionally limited to renal length, shape and cortical thickness. These are regarded as adequate for normal therapeutic decision making and volume measurements are reserved for a few clinical trials. However, there is no evidence concerning the degree to which renal length or volume are...

From November 16–19, 2014, twin researchers of the world will descend on the lovely city of Budapest, Hungary for the 3rd World Congress on Twin Pregnancy, held in conjunction with the 15th Congress of the International Society of Twin Studies (ISTS). It is the first time a Central and Eastern European country will host the congress. On this occasi...

Background: Few, and inconsistent, studies have showed high heritability of some parameters of the anterior segment of the eye; however, no heritability of anterior chamber volume (ACV) has been reported, and no study has been performed to investigate the correlation between the ACV and central corneal thickness (CCT). Methods: Anterior segment...

Much ink has been spilled to describe the emergence and likely influence of the Tea Party on the American political landscape. Pundits and journalists declared that the emergence of the Tea Party movement pushed the Republican Party to a more extreme ideological position, which is generally anti-Washington. To test this hypothesis, we analyzed the...

Spherical equivalent (SE) has not been linked to increased cardiovascular morbidity. Methods: 132 Hungarian twins (age 43.3 +/- 16.9 years) underwent refraction measurements (Huvitz MRK-3100 Premium AutoRefractokeratometer) and oscillometry (TensioMed Arteriograph). Results: Heritability analysis indicated major role for genetic components in the p...

It is well established that women and men differ in their psychological orientation to politics (Burns, Schlozman, and Verba 2001; Dolan 2011; Fox and Lawless 2004; Thomas 2012). In addition to willingness to run for office, expressing interest in politics, and political efficacy, men and women tend to differ in reporting their factual knowledge of...

Almost 40 years ago, evidence from large studies of adult twins and their relatives suggested that between 30 and 60 % of the variance in social and political attitudes could be explained by genetic influences. However, these findings have not been widely accepted or incorporated into the dominant paradigms that explain the etiology of political id...

Electronic noses can distinguish various disorders by analyzing exhaled volatile organic compound (VOC) pattern; however it is unclear how hereditary and environmental backgrounds affect the exhaled VOC pattern. A twin study enrolling monozygotic (MZ) and dizygotic (DZ) twins is an ideal tool to separate the influence of these factors on the exhale...

Aim To estimate heritability and environmental effects on renal parenchymal thickness. Methods In this twin study, renal parenchymal thickness of 98 Hungarian healthy adult twin pairs (68 monozygotic, 30 dizygotic) without kidney disease was measured bilaterally using renal ultrasound with Esaote MyLab 70X ultrasound machine with low-frequency cur...

Arterial stiffness is an independent predictor of cardiovascular, cerebrovascular and all-cause mortality. Quantifying the genetic influence on the stiff arterial phenotype allows us to better predict the development of arterial stiffness. In this study, we aimed to determine the heritability of carotid artery stiffness in healthy twins. We studied...

Twin studies play a role in examining the contribution of genetic variations and environmental factors responsible for the determination of phenotypic variables and of genetic linkage between genotypes. Hungarian twin studies, supported by three twin registries (among them two twin-database), date back to 1970s. Studies mainly focused on various co...

Obesity, blood pressure and arterial stiffness are heritable traits interconnected to each other but their possible common genetic and environmental etiologies are unknown. We studied 228 monozygotic and 150 dizygotic twin pairs aged 18-82 years from Italy, Hungary and the United States, of which 45 monozygotic and 38 dizygotic pairs were discordan...

Objectives This study explains how behavior genetic analysis using a twin design can help us assess the validity of our measures. Methods We test multiple indicators of response propensity, a measure used by survey researchers to better understand the similarities and differences between survey respondents and nonrespondents. The response propensit...

Nitric oxide has an important role in the development of the structure and function of the airways and vessel walls. Fractional exhaled nitric oxide (FENO) is inversely related to the markers and risk factors of atherosclerosis. We aimed to estimate the relative contribution of genes and shared and non-shared environmental influences to variations...

Background: An association between reduced lung function and increased cardiovascular risk has been reported, but the underlying mechanisms are unknown. The aim of this study was to assess the heritability of lung function and to estimate its genetic association with arterial stiffness. Methods: 150 monozygotic and 42 dizygotic healthy Hungarian...

Objective: Altered venous biomechanics may contribute to the pathogenesis of venous diseases, and their heritability is less known. Methods and results: Seventy-eight monozygotic twin pairs (aged 42.4 ± 16.8 years) and 24 same-sex dizygotic twin pairs (aged 50.5 ± 16.1 years) were examined. Anteroposterior and mediolateral diameters of the commo...

Background Structural equation modeling developed as a statistical melding of path analysis and factor analysis that obscured a fundamental tension between a factor preference for multiple indicators and path modeling’s openness to fewer indicators. Discussion Multiple indicators hamper theory by unnecessarily restricting the number of modeled lat...

The first Hungarian Twin Registry was established in Budapest in 1970 through the mandatory reporting of multiple-births. In the 1980s a second, volunteer adult registry was also founded. Unfortunately, both registries ceased to exist in the 1990s. Efforts started in 2006 to revive a Hungarian twin registry. The team spearheading this effort report...

Background and purpose: Few family studies reported moderate genetic impact on the presence and scores of carotid plaques. However, the heritability of carotid plaque characteristics remains still unclear. Twin studies more reliably estimate the relative contribution of genes to these traits in contrast to family study design. Methods: One hundr...

Recent developments in spatial voting have moved beyond finding the most appropriate utility function and started to assess individual differences in decision strategy. The question is not if a proximity or directional worldview performs better in general, rather under what conditions do people pick one strategy over the other? We draw on psycholog...

It has become commonplace to use the ability-motivation-opportunity triad (Luskin, 1990) as a theoretical background for studies on political knowledge. Very little scholarly work was done in the direction of empirically testing the proposed model; more often than not, authors have chosen to operationalize the elements in the triad using suboptimal...