# Probabilistic Contextuality in Physics and Human Behavior

I will present an abstract theory of contextuality in arbitrary systems of measurements. My colleagues and I call
the theory Contextuality-by-Default (CbD). It is essentially about how the identity of the measurements of a given set
of “properties” changes in different contexts (measurement conditions). The identity of a measurement is understood
in the sense of a logically consistent (and empirically unfalsifiable) version of Kolmogorov’s probability theory involving
stochastically unrelated random variables. CbD allows for what we call inconsistent connectedness, involving experimental
errors and interactions (“signaling”) that may cause the measurements of one and the same property in different contexts
to have different distributions. CbD translates into a criterion of (necessary and sufficient conditions for) contextuality in
a broad class of systems, including the intensively studied in quantum physics Klyachko-Can-Binicioğlu-Shumvosky-type,
EPR-Bell-type, and Leggett-Garg-type systems as special cases. Using this criterion one can establish contextuality in
real quantum physics experiments with inconsistent connectedness. By contrast, a wide variety of behavioral data (in the
areas of psychophysics of matching, visual illusions, conceptual comprehension, and polls of public opinion) exhibit no
contextuality and can be explained by “signaling” alone. Time permitting, I will discuss serious methodological problems
in dealing with social data, due to the fact that contextuality can be obtained trivially by averaging over sufficiently
diverse patterns of noncontextual responses.

Literature:

Dzhafarov, E.N., & Kujala, J.V. (in press). Conversations on contextuality. In E.N. Dzhafarov et al. (Eds).
Contextuality from Quantum Physics to Psychology. World Scientific Press. (available as arXiv:1508.00862.)

Dzhafarov, E.N., Kujala, J.V., Larsson, J.-Å., & Cervantes, V.H. (in press). Contextuality-by-Default:
A brief overview of ideas, concepts, and terminology. Lecture Notes in Computer Science. (available as
arXiv:1504.00530.)

Additional:

Dzhafarov, E.N., & Kujala, J.V., & Larsson, J.-Å. (2015). Contextuality in three types of quantum-mechanical
systems. Foundations of Physics 7, 762-782.

Dzhafarov, E.N., Zhang, R., & Kujala, J.V. (in press). Is there contextuality in behavioral and social systems?
Philosophical Transactions of the Royal Society A. (available as arXiv:1504.07422.)

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