Statistics, Causality and Bell's Theorem

Bell's [Physics 1 (1964) 195-200] theorem is popularly supposed to establish the nonlocality of quantum physics. Violation of Bell's inequality in experiments such as that of Aspect, Dalibard and Roger [Phys. Rev. Lett. 49 (1982) 1804-1807] provides empirical proof of nonlocality in the real world. This paper reviews recent work on Bell's theorem, linking it to issues in causality as understood by statisticians. The paper starts with a proof of a strong, finite sample, version of Bell's inequality and thereby also of Bell's theorem, which states that quantum theory is incompatible with the conjunction of three formerly uncontroversial physical principles, here referred to as locality, realism and freedom. Locality is the principle that the direction of causality matches the direction of time, and that causal influences need time to propagate spatially. Realism and freedom are directly connected to statistical thinking on causality: they relate to counterfactual reasoning, and to randomisation, respectively. Experimental loopholes in state-of-the-art Bell type experiments are related to statistical issues of post-selection in observational studies, and the missing at random assumption. They can be avoided by properly matching the statistical analysis to the actual experimental design, instead of by making untestable assumptions of independence between observed and unobserved variables. Methodological and statistical issues in the design of quantum Randi challenges (QRC) are discussed. The paper argues that Bell's theorem (and its experimental confirmation) should lead us to relinquish not locality, but realism.Comment: Published in at http://dx.doi.org/10.1214/14-STS490 the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

Conspiratorial beliefs observed through entropy principles

We propose a novel approach framed in terms of information theory and entropy to tackle the issue of conspiracy theories propagation. We start with the report of an event (such as 9/11 terroristic attack) represented as a series of individual strings of information denoted respectively by two-state variable Ei=+/-1, i=1,..., N. Assigning Ei value to all strings, the initial order parameter and entropy are determined. Conspiracy theorists comment on the report, focusing repeatedly on several strings Ek and changing their meaning (from -1 to +1). The reading of the event is turned fuzzy with an increased entropy value. Beyond some threshold value of entropy, chosen by simplicity to its maximum value, meaning N/2 variables with Ei=1, doubt prevails in the reading of the event and the chance is created that an alternative theory might prevail. Therefore, the evolution of the associated entropy is a way to measure the degree of penetration of a conspiracy theory. Our general framework relies on online content made voluntarily available by crowds of people, in response to some news or blog articles published by official news agencies. We apply different aggregation levels (comment, person, discussion thread) and discuss the associated patterns of entropy change.Comment: 21 page, 14 figure

Social Media and Fake News in the 2016 Election

Following the 2016 U.S. presidential election, many have expressed concern about the effects of false stories ("fake news"), circulated largely through social media. We discuss the economics of fake news and present new data on its consumption prior to the election. Drawing on web browsing data, archives of fact-checking websites, and results from a new online sur-vey, we find:(i) social media was an important but not dominant source of election news, with14 percent of Americans calling social media their "most important" source;(ii) of the known false news stories that appeared in the three months before the election, those favoring Trump were shared a total of 30 million times on Facebook, while those favoring Clinton were shared8 million times;(iii) the average American adult saw on the order of one or perhaps several fake news stories in the months around the election, with just over half of those who recalled seeing them believing them; and(iv) people are much more likely to believe stories that favor their preferred candidate, especially if they have ideologically segregated social media networks

Politics and Strategy in Judicial Decision-Making: Evidence from federal human trafficking sentencing

This thesis investigates the effects of judicial ideology and judge characteristics on sentencing in human trafficking cases. Despite research on federal prosecutions of human trafficking, almost nothing is known about sentencing for federal human trafficking offenders. Previous research on sentencing has been limited by the lack of data linking judges to specific sentencing decisions. Using new data that matches judges to defendants convicted of federal human trafficking offenses, I observe that judicial ideology has an effect on overall sentence length—but only for district court judges appointed by Democratic presidents. I also find that partisan composition of the circuit court, rather than ideology of the sentencing judge, affects the likelihood of downward departures from the Sentencing Guidelines. When Democrat-appointed judges make up a majority of the circuit court, district court judges are 2.1 times as likely to depart below the Sentencing Guidelines. These findings confirm positive political theories of sentencing that model judges as strategic decision makers within a "judicial hierarchy."Undergraduate Research ScholarshipNo embargoAcademic Major: PhilosophyAcademic Major: Political Scienc

The Costs of Judging Judges by the Numbers

This essay discredits current empirical models that are designed to “judge” or rank appellate judges, and then assesses the harms of propagating such models. First, the essay builds on the discussion of empirical models by arguing that (1) the judicial virtues that the legal empiricists set out to measure have little bearing on what actually makes for a good judge; and (2) even if they did, the empiricists’ chosen variables have not measured those virtues accurately. The essay then concludes that by generating unreliable claims about the relative quality of judges, these studies mislead both decision-makers and the public, degrade discussions of judging, and could, if taken seriously, detrimentally alter the behavior of judges themselves

Measuring belief in conspiracy theories: Validation of a French and English single-item scale

We designed, in French and in English, a single-item scale to measure people’s general tendency to believe in conspiracy theories. The validity and reliability of this scale was assessed in 3 studies (total N = 555). In Study 1 (N = 152), positive correlations between the single-item scale and 3 other conspiracy belief scales on a French student sample suggested good concurrent validity. In Study 2 (N = 292), we replicated these results on a larger and more heterogeneous Internet American sample. Moreover, the scale showed good predictive validity—responses predicted participants’ willingness to receive a bi-monthly newsletter about alleged conspiracy theories. Finally, in Study 3 (N = 111), we observed good test-retest reliability and demonstrated both convergent and discriminant validity of the single-item scale. Overall these results suggest that the single-item conspiracy belief scale has good validity and reliability and may be used to measure conspiracy belief in favor of lengthier existing scales. In addition, the validation of the single-item scale led us to develop and start validating French versions of the Generic Conspiracist Beliefs scale, the Conspiracy Mentality Questionnaire, and a 10-item version (instead of the 15-item original version) of the Belief in Conspiracy Theories Inventory

Bell inequalities for random fields

The assumptions required for the derivation of Bell inequalities are not usually satisfied for random fields in which there are any thermal or quantum fluctuations, in contrast to the general satisfaction of the assumptions for classical two point particle models. Classical random field models that explicitly include the effects of quantum fluctuations on measurement are possible for experiments that violate Bell inequalities.Comment: 18 pages; 1 figure; v4: Essentially the published version; extensive improvements. v3: Better description of the relationship between classical random fields and quantum fields; better description of random field models. More extensive references. v2: Abstract and introduction clarifie