Quantum cognition research applies abstract, mathematical principles of quantum theory to inquiries in cognitive science. It differs fundamentally from alternative speculations about quantum brain processes. This topic presents new developments within this research program. In the introduction to this topic, we try to answer three questions: Why apply quantum concepts to human cognition? How is quantum cognitive modeling different from traditional cognitive modeling? What cognitive processes have been modeled using a quantum account? In addition, a brief introduction to quantum probability (...) theory and a concrete example is provided to illustrate how a quantum cognitive model can be developed to explain paradoxical empirical findings in psychological literature. (shrink)

Similar problems keep reappearing in both the discussion about the “hard” problem of consciousness and in fundamental issues in quantum theory. We argue that the similarities are due to common problems within the conceptual foundations of both fields. In quantum physics, the state reduction marks the “coming into being” of a new aspect of reality for which no causal explanation is available. Likewise, the self-referential nature of consciousness constitutes a “coming into being” of a new quality which goes beyond a (...) fully causal account of reality. Both subjects require a categorical scheme which is significantly richer then the one used in addressing factual aspects of reality alone. While parts of this categorical scheme are realized in the formalism of quantum theory, they are seldom applied in the context of consciousness. We show what the structural limitations of a classical categorical framework are, how a richer framework can be developed, and how it can be applied to both quantum physics and consciousness. (shrink)

Mental representations are based upon categories in which the state of a mental system is stable. Acategorial states, on the other hand, are distinguished by unstable behavior. A refined and compact terminology for the description of categorial and acategorial mental states and their stability properties is introduced within the framework of the theory of dynamical systems. The relevant concepts are illustrated by selected empirical observations in cognitive neuroscience. Alterations of the category of the first person singular and features of creative (...) activity will be discussed as examples for the phenomenology of acategorial states. (shrink)

We analyze different aspects of our quantum modeling approach of human concepts and, more specifically, focus on the quantum effects of contextuality, interference, entanglement, and emergence, illustrating how each of them makes its appearance in specific situations of the dynamics of human concepts and their combinations. We point out the relation of our approach, which is based on an ontology of a concept as an entity in a state changing under influence of a context, with the main traditional concept theories, (...) that is, prototype theory, exemplar theory, and theory theory. We ponder about the question why quantum theory performs so well in its modeling of human concepts, and we shed light on this question by analyzing the role of complex amplitudes, showing how they allow to describe interference in the statistics of measurement outcomes, while in the traditional theories statistics of outcomes originates in classical probability weights, without the possibility of interference. The relevance of complex numbers, the appearance of entanglement, and the role of Fock space in explaining contextual emergence, all as unique features of the quantum modeling, are explicitly revealed in this article by analyzing human concepts and their dynamics. (shrink)

The main formal structures of generalized quantum theory are summarized. Recent progress has sharpened some of the concepts, in particular the notion of an observable, the action of an observable on states (putting more emphasis on the role of proposition observables), and the concept of generalized entanglement. Furthermore, the active role of the observer in the structure of observables and the partitioning of systems is emphasized.

Temporally non-local measurements -- single measurements yielding information about the state of a system at different instances-- may provide a way to observe non-classical behaviour in mental systems. The signature for such behaviour is a violation of temporal Bell inequalities. We present such inequalities applicable to scenarios with two alternating mental states, such as in the perception of ambiguous figures. We indicate empirical options for testing temporal Bell inequalities, and speculate about possible explanations in case these inequalities are indeed violated.

The concepts of complementarity and entanglement are considered with respect to their significance in and beyond physics. A formally generalized, weak version of quantum theory, more general than ordinary quantum theory of physical systems, is outlined and tentatively applied to two examples.

The rise of quantum information theory has lent new relevance to experimental tests for non-classicality, particularly in controversial cases such as adiabatic quantum computing superconducting circuits. The Leggett-Garg inequality is a “Bell inequality in time” designed to indicate whether a single quantum system behaves in a macrorealistic fashion. Unfortunately, a violation of the inequality can only show that the system is either (i) non-macrorealistic or (ii) macrorealistic but subjected to a measurement technique that happens to disturb the system. The “clumsiness” (...) loophole (ii) provides reliable refuge for the stubborn macrorealist, who can invoke it to brand recent experimental and theoretical work on the Leggett-Garg test inconclusive. Here, we present a revised Leggett-Garg protocol that permits one to conclude that a system is either (i) non-macrorealistic or (ii) macrorealistic but with the property that two seemingly non-invasive measurements can somehow collude and strongly disturb the system. By providing an explicit check of the invasiveness of the measurements, the protocol replaces the clumsiness loophole with a significantly smaller “collusion” loophole. (shrink)

1 – Institute for Frontier Areas of Psychology and Mental Health, Wilhelmstr. 3a, 79098 Freiburg, Germany 2 – Parmenides Center, Via Mellini 26-28, 57031 Capoliveri, Italy 3 – Department of Ophtalmology, University of Freiburg, Killianstr. 5, 79106 Freiburg, Germany 4 – Institute of Physics, University of Freiburg, Hermann- Herder -Str. 3, 79104 Freiburg, GermanyThe “Necker-Zeno model”, a model for bistable perception inspired by the quantum Zeno effect, was previously used to relate three basic time scales of cognitive relevance to one (...) another in a quantitative manner. In this paper, the model predictions are compared with experimental results obtained under discontinuous presentation of an ambiguous stimulus. In addition to earlier results for long inter-stimulus intervals, we show that the reversal dynamics according to the Necker-Zeno model is also in agreement with new results for short inter-stimulus intervals. Moreover, we refine the model in such a way that it accounts for the distribution of “dwell times”. Finally, we indicate applications concerning the modification of cognitive time scales under conditions of psychopathological impairments and meditationinduced modes of awareness. ∗Address correspondence to this author at the Theory Division of the Institute for Frontier Areas of Psychology, Wilhelmstr. 3a, D–79098 Freiburg, Germany; E-mail: [email protected]. (shrink)