Quantum contextuality and cognitive contextuality: The significance of violations of Bell-type inequalities

Abstract

Quantum contextuality (or non-locality called “spooky action at a distance” by Einstein) is witnessed by violations of Bell-type inequalities, which are purely statistical inequalities and can in principle be applied to any statistical correlations observed in empirical experiments. It has been reported recently that Bell-type inequalities are violated in cognitive experiments, which formally shows that contextuality does exist in cognition as well as physical reality. It is unclear, however, whether quantum and cognitive contextualities are essentially the same kind of phenomena, and the nature of cognitive contextuality has been debated whereas the nature of quantum contextuality has been explicated by foundational physicists and philosophers of physics. In the present paper, thus, we aim at elucidating similarities and dissimilarities between quantum and cognitive contextualities. We argue, in particular, that cognitive contextuality as shown by the violation of Bell-type inequalities never entails that the brain is indeterministic; rather, cognitive contextuality is caused by the statistical nature of collective state dynamics and the special structure of experimental set-ups, whereas quantum contextuality is caused by the statistical nature of single state dynamics and the existence of special states or operations.