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Ehtibar N. Dzhafarov - One of the best experts on this subject based on the ideXlab platform.
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true contextuality beats direct influences in human decision making
Journal of Experimental Psychology: General, 2019Co-Authors: Irina Basieva, Ehtibar N. Dzhafarov, Victor H Cervantes, Andrei KhrennikovAbstract:In quantum physics there are well-known situations when measurements of the same property in different contexts (under different conditions) have the same probability distribution but cannot be represented by one and the same random variable. Such systems of random variables are called contextual. More generally, true contextuality is observed when different contexts force measurements of the same property (in psychology, responses to the same question) to be more dissimilar random variables than warranted by the difference of their distributions. The difference in distributions is itself a form of context-dependence but of another nature: it is attributable to direct causal influences exerted by contexts upon the random variables. The Contextuality-by-Default Theory allows one to separate true contextuality from direct influences in the overall context-dependence. The Contextuality-by-Default analysis of numerous previous attempts to demonstrate contextuality in human judgments shows that all context-dependence in them can be accounted for by direct influences, with no true contextuality present. However, contextual systems in human behavior can be found. In this paper we present a series of crowd-sourcing experiments that exhibit true contextuality in simple decision making. The design of these experiments is an elaboration of one introduced in the Snow Queen experiment (Decision 5, 193-204, 2018), in which contextuality was for the first time demonstrated unequivocally. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
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On universality of classical probability with contextually labeled random variables: Response to A. Khrennikov
Journal of Mathematical Psychology, 2019Co-Authors: Ehtibar N. Dzhafarov, Maria KonAbstract:Abstract In his constructive and well-informed commentary, Andrei Khrennikov acknowledges a privileged status of classical probability Theory with respect to statistical analysis. He also sees advantages offered by the Contextuality-by-Default Theory, notably, that it “demystifies quantum mechanics by highlighting the role of contextuality,” and that it can detect and measure contextuality in inconsistently connected systems. He argues, however, that classical probability Theory may have difficulties in describing empirical phenomena if they are described entirely in terms of observable events. We disagree: contexts in which random variables are recorded are as observable as the variables’ values. Khrennikov also argues that the Contextuality-by-Default Theory suffers the problem of non-uniqueness of couplings. We disagree that this is a problem: couplings are all possible ways of imposing counterfactual joint distributions on random variables that de facto are not jointly distributed. The uniqueness of modeling experiments by means of quantum formalisms brought up by Khrennikov is achieved for the price of additional, substantive assumptions. This is consistent with our view of quantum Theory as a special-purpose generator of classical probabilities. Khrennikov raises the issue of “mental signaling,” by which he means inconsistent connectedness in behavioral systems. Our position is that it is as inherent to behavioral systems as their stochasticity.
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context content systems of random variables the contextuality by Default Theory
Journal of Mathematical Psychology, 2016Co-Authors: Ehtibar N. Dzhafarov, Janne V KujalaAbstract:Abstract This paper provides a systematic yet accessible presentation of the Contextuality-by-Default Theory. The consideration is confined to finite systems of categorical random variables, which allows us to focus on the basics of the Theory without using full-scale measure-theoretic language. Contextuality-by-Default is a Theory of random variables identified by their contents and their contexts, so that two variables have a joint distribution if and only if they share a context. Intuitively, the content of a random variable is the entity the random variable measures or responds to, while the context is formed by the conditions under which these measurements or responses are obtained. A system of random variables consists of stochastically unrelated “bunches,” each of which is a set of jointly distributed random variables sharing a context. The variables that have the same content in different contexts form “connections” between the bunches. A probabilistic coupling of this system is a set of random variables obtained by imposing a joint distribution on the stochastically unrelated bunches. A system is considered noncontextual or contextual according to whether it can or cannot be coupled so that the joint distributions imposed on its connections possess a certain property (in the present version of the Theory, “maximality”). We present a criterion of contextuality for a special class of systems of random variables, called cyclic systems. We also introduce a general measure of contextuality that makes use of (quasi-)couplings whose distributions may involve negative numbers or numbers greater than 1 in place of probabilities.
Nicola Olivetti - One of the best experts on this subject based on the ideXlab platform.
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a sequent calculus for skeptical Default logic
Theorem Proving with Analytic Tableaux and Related Methods, 1997Co-Authors: Piero A. Bonatti, Nicola OlivettiAbstract:In this paper, we contribute to the proof-Theory of Reiter's Default Logic by introducing a sequent calculus for skeptical reasoning. The main features of this calculus are simplicity and regularity, and the fact that proofs can be surprisingly concise and, in many cases, involve only a small part of the Default Theory.
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TABLEAUX - A Sequent Calculus for Skeptical Default Logic
Lecture Notes in Computer Science, 1997Co-Authors: Piero A. Bonatti, Nicola OlivettiAbstract:In this paper, we contribute to the proof-Theory of Reiter's Default Logic by introducing a sequent calculus for skeptical reasoning. The main features of this calculus are simplicity and regularity, and the fact that proofs can be surprisingly concise and, in many cases, involve only a small part of the Default Theory.
Enrico Pontelli - One of the best experts on this subject based on the ideXlab platform.
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reasoning about actions and planning with preferences using prioritized Default Theory
Computational Intelligence, 2004Co-Authors: Tran Cao Son, Enrico PontelliAbstract:This paper shows how action theories, expressed in an extended version of the language , can be naturally encoded using Prioritized Default Theory. We also show how prioritized Default Theory can be extended to express preferences between rules. This extension provides a natural framework to introduce different types of preferences in action theories—preferences between actions and preferences between final states. In particular, we demonstrate how these preferences can be expressed within extended prioritized Default Theory. We also discuss how this framework can be implemented in terms of answer set programming.
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reasoning about actions in prioritized Default Theory
European Conference on Logics in Artificial Intelligence, 2002Co-Authors: Tran Cao Son, Enrico PontelliAbstract:This paper shows how action Theory in the language B can be naturally encoded using prioritized Default Theory. We also show how prioritized Default Theory can be extended to express preferences between rules and formulae. This extension provides a natural framework to introduce preferences over trajectories in B. We illustrate how these preferences can be expressed and how they can be represented within extended prioritized Default Theory. We also discuss how this framework can be implemented in terms of answer set programming.
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JELIA - Reasoning about Actions in Prioritized Default Theory
Logics in Artificial Intelligence, 2002Co-Authors: Enrico PontelliAbstract:This paper shows how action Theory in the language B can be naturally encoded using prioritized Default Theory. We also show how prioritized Default Theory can be extended to express preferences between rules and formulae. This extension provides a natural framework to introduce preferences over trajectories in B. We illustrate how these preferences can be expressed and how they can be represented within extended prioritized Default Theory. We also discuss how this framework can be implemented in terms of answer set programming.
Janne V Kujala - One of the best experts on this subject based on the ideXlab platform.
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context content systems of random variables the contextuality by Default Theory
Journal of Mathematical Psychology, 2016Co-Authors: Ehtibar N. Dzhafarov, Janne V KujalaAbstract:Abstract This paper provides a systematic yet accessible presentation of the Contextuality-by-Default Theory. The consideration is confined to finite systems of categorical random variables, which allows us to focus on the basics of the Theory without using full-scale measure-theoretic language. Contextuality-by-Default is a Theory of random variables identified by their contents and their contexts, so that two variables have a joint distribution if and only if they share a context. Intuitively, the content of a random variable is the entity the random variable measures or responds to, while the context is formed by the conditions under which these measurements or responses are obtained. A system of random variables consists of stochastically unrelated “bunches,” each of which is a set of jointly distributed random variables sharing a context. The variables that have the same content in different contexts form “connections” between the bunches. A probabilistic coupling of this system is a set of random variables obtained by imposing a joint distribution on the stochastically unrelated bunches. A system is considered noncontextual or contextual according to whether it can or cannot be coupled so that the joint distributions imposed on its connections possess a certain property (in the present version of the Theory, “maximality”). We present a criterion of contextuality for a special class of systems of random variables, called cyclic systems. We also introduce a general measure of contextuality that makes use of (quasi-)couplings whose distributions may involve negative numbers or numbers greater than 1 in place of probabilities.
Piero A. Bonatti - One of the best experts on this subject based on the ideXlab platform.
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a sequent calculus for skeptical Default logic
Theorem Proving with Analytic Tableaux and Related Methods, 1997Co-Authors: Piero A. Bonatti, Nicola OlivettiAbstract:In this paper, we contribute to the proof-Theory of Reiter's Default Logic by introducing a sequent calculus for skeptical reasoning. The main features of this calculus are simplicity and regularity, and the fact that proofs can be surprisingly concise and, in many cases, involve only a small part of the Default Theory.
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TABLEAUX - A Sequent Calculus for Skeptical Default Logic
Lecture Notes in Computer Science, 1997Co-Authors: Piero A. Bonatti, Nicola OlivettiAbstract:In this paper, we contribute to the proof-Theory of Reiter's Default Logic by introducing a sequent calculus for skeptical reasoning. The main features of this calculus are simplicity and regularity, and the fact that proofs can be surprisingly concise and, in many cases, involve only a small part of the Default Theory.
