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Muslim Americans constitute one of the United States’ most vulnerable minority groups, facing frequent discrimination from both the public and the government. Despite this vulnerability, few studies evaluate interventions for reducing prejudice against Muslim Americans. Building from an insightful literature on the sources of prejudice against Muslim Americans, this paper tests whether attitudes can be improved with information countering misperceptions of the community as particularly foreign, threatening, and disloyal to the United States. The experimental treatment modestly improved attitudes, including among some subgroups predisposed to prejudice against Muslim Americans. However, the treatment struggled to change policy views, and it demonstrated some vulnerability to social desirability bias and priming on terrorism threats. The findings suggest that information campaigns addressing misperceptions can help to reduce prejudice on the margins, but primarily in less politicized contexts.
In the first half of the nineteenth century, many Americans visited phrenological practitioners. Some clients were true believers, who consulted phrenology to choose an occupation, select a marriage partner and raise children. But, as this article demonstrates, many others consumed phrenology as an ‘experiment’, testing its validity as they engaged its practice. Consumers of ‘practical phrenology’ subjected themselves to examinations often to test the phrenologist and his practice against their own knowledge of themselves. They also tested whether phrenology was true, according to their own beliefs about race and gender. While historians have examined phrenology as a theory of the mind, we know less about its ‘users’ and how gender, race and class structured their engagement. Based on extensive archival research with letters and diaries, memoirs and marginalia, as well as phrenological readings, this study reveals how a continuum of belief existed around phrenology, from total advocacy to absolute denunciation, with lots of room for acceptance and rejection in between. Phrenologists’ notebooks and tools of salesmanship also show how an experimental environment emerged where phrenologists themselves embraced a culture of testing. In an era of what Katherine Pandora has described as ‘epistemological contests’, audiences confronted new museums, performances and theatres of natural knowledge and judged their validity. This was also true for phrenology, which benefited from a culture of contested authority. As this article reveals, curiosity, experimentation and even scepticism among users actually helped keep phrenology alive for decades.
To date, cyber security research is built on observational studies involving macro-level attributes as causal factors that account for state behaviour in cyberspace. While this tradition resulted in significant findings, it abstracts the importance of individual decision-makers. Specifically, these studies have yet to provide an account as to why states fail to integrate available information resulting in suboptimal judgements such as the misattribution of cyber operations. Using a series of vignette experiments, the study demonstrates that cognitive heuristics and motivated reasoning play a crucial role in the formation of judgements vis-à-vis cyberspace. While this phenomenon is frequently studied relative to the physical domain, it remains relatively unexplored in the context of cyberspace. Consequently, this study extends the existing literature by highlighting the importance of micro-level attributes in interstate cyber interactions.
Chapter 13 addresses issues associated with experimental techniques for investigating hydrodynamic instabilties. These issues include the experimental facility, model configuration and instrumentation, all of which impact our understanding of hydrodynamic instabilities.
This paper investigates how we infer the status of others from their social relationships. In a series of experimental studies, we test the effects of a social relationship's type and direction on the status judgments of others. We demonstrate empirically, possibly for the first time, a widely-assumed connection between network structure and perceptions of status; that is, that observers do infer the status positions of group members from their relationships. Moreover, we find that observers' status judgments vary with the direction and type of social relationship. We theorize that underlying this variance in status judgments are two relational schemas which differentially influence the processing of the observed social ties. Our finding that only the linear-ordering schema leads to status inferences provides an important scope condition to prior research on network cognition, and specifically on the perceptions of social status.
In recent decades, parasite community ecology has produced hundreds of studies on an ever-growing number of host species, and developed into an active sub-discipline of parasitology. However, this growth has been characterized by a lack of standards in the practices used by researchers, with many common approaches being flawed, unjustified or misleading. Here, in the hope of promoting advances in the study of parasite community ecology, I identify some of the most common errors or weaknesses in past studies, and propose ten simple rules for best practice in the field. They cover issues including, among others, taxonomic resolution, proper and justifiable analytical methods, higher-level replication, controlling for sampling effort or species richness, accounting for spatial distances, using experimental approaches, and placing raw data in the public domain. While knowledge of parasite communities has expanded in breadth, with more and more host species being studied, true progress has been very limited with respect to our understanding of fundamental general processes shaping these communities. It is hoped that the guidelines presented here can direct researchers away from the entrenched use of certain approaches flawed in design, analysis or interpretation, by offering a more rigorous and standardized set of practices, and, hopefully, a way forward.
Companies that manage mandatory pension funds are frequently accused of excessive fee taking. International analyses have found that in countries with legal caps, commissions remain within these caps; hence, market competition does not function. Surprisingly, there are few international cases where local regulators implement mechanisms to facilitate competition. The variety of auction mechanisms available raises the question of whether an optimal solution exists for this purpose. Therefore, in this study, we present evidence, based on a controlled regulatory experiment, on the fee-reduction potential of reverse auctions.
Researchers are interested in running experiments in the Middle East and North Africa (MENA), which often include financially incentivized measures of risk preferences. However, it can be that gambling is forbidden and these measures may either be illegal or result in non-random refusal of subjects to participate. If individuals derive utility from warm glow or otherwise enjoy giving, then risk preferences apply to that utility too. Even in the absence of personal stakes, if risk will be borne by others, warm glow will lead subjects to behave in a manner consistent with their preferences over risk for private consumption. I examine how paid risk elicitation mechanisms correlate with measures incentivized by charitable contributions. Results suggest that subjects behave almost identically under paid and charitable stakes. Charitable measures may provide behavioral means by which to measure risk preferences, in populations where gambling is forbidden.
A pressing question during the first half-decade of the third plague pandemic (1894–9) was what was a ‘suitable soil’ for the disease. The question related to plague’s perceived ability to disappear from a given city only to reappear at some future point; a phenomenon that became central to scientific investigations of the disease. However, rather than this simply having a metaphorical meaning, the debate around plague’s ‘suitable soil’ actually concerned the material reality of the soil itself. The prevalence of plague in the working-class neighbourhood of Taipingshan during the first major outbreak of the pandemic, in 1894 in Hong Kong, led to an extensive debate regarding the ability of the soil to harbour and even spread the disease. Involving experiments, which were seen as able to procure evidence for or against the demolition or even torching of the area, scientific and administrative concerns over the soil rendered it an unstable yet highly productive epistemic thing. The spread of plague to India further fuelled concerns over the ability of the soil to act as the medium of the disease’s so-called true recrudescence. Besides high-profile scientific debates, hands-on experiments on purifying the soil of infected houses by means of highly intrusive methods allowed scientists and administrators to act upon and further solidify plague’s supposed invisibility in the urban terrain. Rather than being a short-lived, moribund object of epidemiological concern, this paper will demonstrate that the soil played a crucial role in the development of plague as a scientifically knowable and actionable category for modern medicine.
Competition in a multi-unit auction is measured both by the number of bidders and by the relative size of their demands, compared to the number of units on sale. For the same degree of competition (identical aggregate demand and supply), we can observe different demand structures. Do they have an impact on the auction efficiency and revenue-raising properties? It is essential to understand better the impact of competition structure on performance in order to draw recommendations for the design of multi-unit auctions. Theoretical results demonstrate on a simple case contrasting a uniform-price auction of two bidders with a demand of 6 units each, and an auction of 6 bidders with a demand of two units each, that there are multiple equilibria leading to different performance outcome. Experiments are conducted to compare the performance of these two auctions. Results support that with a constant competition degree, the seller gets higher expected revenue with a lower variance when he faces a large number of bidders with small individual demands. We show that this result is attained with no significant effect on allocative efficiency.
Democratic theorists often envision public deliberation as being essential to the working of democracy. Several scholars have also highlighted a potential for realising such deliberations on the internet. Consequentially, an emerging array of experiments in online deliberation has now been developed to achieve online discussions, which would be beneficial for democracy. However, few studies have yet attempted to compare the outcomes of online mini-publics to online citizens’ discussions in general. This article, thus, concerns an online experiment carried out in 2013 with the purpose of examining whether, and under which conditions, forums designed according to deliberative principles produce better ‘democratic outcomes’ – such as coherence of opinions, increased efficacy, trust, and propensity for civic participation – than online citizens’ discussions, which are ‘left to their own devices’. The study applies a post-test only, 2×2 factorial design, with a control group. In total, N=70 participants taking part in the experiment. The findings indicate that the effects of designing for deliberation were generally positive, albeit not for all of the democratic outcomes. In addition, methodological issues of relevance for the internal and external validity of the current experiment, which could be of relevance for future studies, are also brought forth.
Experimentation is an increasingly popular method among political scientists. While experiments are highly advantageous for creating internally valid conclusions, they are often criticized for being low on external validity. Critical to questions of external validity are the types of subjects who participate in a given experiment, with scholars typically arguing that samples of adults are more externally valid then student samples. Despite the vociferousness of such arguments, these claims have received little empirical treatment. In this paper we empirically test for key differences between student and adult samples by conducting four parallel experiments on each of the three samples commonly used by political scientists. We find that our student and diverse, national adult sample behave consistently and in line with theoretical predictions once relevant moderators are taken into account. The same is not true for our adult convenience sample.
The study aims at examining the behaviour of electromagnetic actuator as inductive
sensor. The electromagnets are integrated in an alternative Wheatstone bridge and powered
with alternative tension. This circuit allows the measurement of the electromagnet
inductance variation, and as this variation is a function of the air gap, the displacement
can be deduced. The effect of eddy currents is assessed in order to choose the suitable
bridge frequency. Finally, a demodulator is used to obtain the tension proportional to the
air gap value. The behaviour is assessed experimentally. Experiments are carried out on a
simple beam; clamped at one end and simply supported at the other. The displacements could
be measured by using four eddy current sensors and the inductive sensor. The inductive
sensor displacement and a modal approximation of the four eddy current sensors resulting
from impact testing are compared. Analysis of the results obtained predicts an efficient
and robust behaviour.
Economists and biologists have proposed a distinction between two mechanisms – “strong” and “weak” reciprocity – that may explain the evolution of human sociality. Weak reciprocity theorists emphasize the benefits of long-term cooperation and the use of low-cost strategies to deter free-riders. Strong reciprocity theorists, in contrast, claim that cooperation in social dilemma games can be sustained by costly punishment mechanisms, even in one-shot and finitely repeated games. To support this claim, they have generated a large body of evidence concerning the willingness of experimental subjects to punish uncooperative free-riders at a cost to themselves. In this article, I distinguish between a “narrow” and a “wide” reading of the experimental evidence. Under the narrow reading, punishment experiments are just useful devices to measure psychological propensities in controlled laboratory conditions. Under the wide reading, they replicate a mechanism that supports cooperation also in “real-world” situations outside the laboratory. I argue that the wide interpretation must be tested using a combination of laboratory data and evidence about cooperation “in the wild.” In spite of some often-repeated claims, there is no evidence that cooperation in the small egalitarian societies studied by anthropologists is enforced by means of costly punishment. Moreover, studies by economic and social historians show that social dilemmas in the wild are typically solved by institutions that coordinate punishment, reduce its cost, and extend the horizon of cooperation. The lack of field evidence for costly punishment suggests important constraints about what forms of cooperation can or cannot be sustained by means of decentralised policing.
The current underlying assumption in most geochemical studies of granitic rocks is that granitic magmas reflect their source regions. However, the mechanisms by which source rocks control the intensive and compositional parameters of the magmas remain poorly known. Recent experimental data are used to evaluate the ‘source rock model’ and to discuss controls of (1) redox states and (2) the Sr isotopic compositions of granitic magmas.
Experimental studies have been performed in parallel on biotite-muscovite and tourmaline-muscovite leucogranites from the High Himalayas. Results under reducing conditions ( = FMQ – 0·5) at 4 kbar and variable suggest that the tourmaline-muscovite granite evolved under progressively more oxidising conditions during crystallisation, up to values more than four log units above the FMQ buffer. Leucogranite magmas thus provide an example of the control of redox conditions by post-segregation rather than by partial melting processes.
Other experiments designed to test the mechanisms of isotopic equilibration of Sr during partial melting of a model crustal assemblage show that kinetic factors can dominate the isotopic signature in the case of source rocks not previously homogenised during an earlier metamorphic event. The possibility is therefore raised that partial melts may not necessarily reflect the Sr isotopic composition of their sources, weakening in a fundamental way the source rock model.
Massive stars end their life with the gravitational collapse of their core and the formation of a neutron star. Their explosion as a supernova depends on the revival of a spherical accretion shock, located in the inner 200km and stalled during a few hundred milliseconds. Numerical simulations suggest that the large scale asymmetry of the neutrino-driven explosion is induced by a hydrodynamical instability named SASI. Its non radial character is able to influence the kick and the spin of the resulting neutron star. The SWASI experiment is a simple shallow water analog of SASI, where the role of acoustic waves and shocks is played by surface waves and hydraulic jumps. Distances in the experiment are scaled down by a factor one million, and time is slower by a factor one hundred. This experiment is designed to illustrate the asymmetric nature of core-collapse supernova.
Behavioral scientists routinely publish broad claims about human psychology and behavior in the world's top journals based on samples drawn entirely from Western, Educated, Industrialized, Rich, and Democratic (WEIRD) societies. Researchers – often implicitly – assume that either there is little variation across human populations, or that these “standard subjects” are as representative of the species as any other population. Are these assumptions justified? Here, our review of the comparative database from across the behavioral sciences suggests both that there is substantial variability in experimental results across populations and that WEIRD subjects are particularly unusual compared with the rest of the species – frequent outliers. The domains reviewed include visual perception, fairness, cooperation, spatial reasoning, categorization and inferential induction, moral reasoning, reasoning styles, self-concepts and related motivations, and the heritability of IQ. The findings suggest that members of WEIRD societies, including young children, are among the least representative populations one could find for generalizing about humans. Many of these findings involve domains that are associated with fundamental aspects of psychology, motivation, and behavior – hence, there are no obvious a priori grounds for claiming that a particular behavioral phenomenon is universal based on sampling from a single subpopulation. Overall, these empirical patterns suggests that we need to be less cavalier in addressing questions of human nature on the basis of data drawn from this particularly thin, and rather unusual, slice of humanity. We close by proposing ways to structurally re-organize the behavioral sciences to best tackle these challenges.
We illustrate the experimental method by examining bidding behavior for controversial goods, i.e., goods in which bidders have positive and negative values. Our results suggest that bidding behavior differs across auction type. Bidders with positive induced values bid sincerely in a WTP auction. Bidders bid conservatively, however, in the WTA auction, foregoing profitable opportunities. Informing bidders of their optimal strategy serves to attenuate bidding discrepancies but does not eliminate them. Treating the WTP and WTA auctions as equivalent given positive and negative values could lead one to overstate the costs relative to the benefits of the controversial good.
The effective design and implementation of interventions that reduce vulnerability and poverty require a solid understanding of underlying poverty dynamics and associated behavioral responses. Stochastic and dynamic benefit streams can make it difficult for the poor to learn the value of such interventions to them. We explore how dynamic field experiments can help (i) intended beneficiaries to learn and understand these complicated benefit streams, and (ii) researchers to better understand how the poor respond to risk when faced with nonlinear welfare dynamics. We discuss and analyze dynamic risk valuation experiments in Morocco, Peru, and Kenya.
We explore the effects of recommended play and the presentation of payoff information on behavior in an ambient-based policy instrument experiment. Specifically, we test the effects of recommended play (via a description of marginal decision making) and a payoff table on the behavior of individuals facing an ambient-based policy instrument. We find that recommended play and the presentation of a payoff table increases the use of the socially optimal strategy, thereby increasing efficiency. These results suggest that providing decision makers with a richer description of the decision making environment significantly reduces decision error, significantly improving the efficiency of ambient-based policy instruments.