Hybrid-Logical Proofs at Work in Cognitive Psychology

The overall aim of this project is to use logic to investigate psychological reasoning tests, in particular what are called false-belief tests. Children with Autism Spectrum Disorder (ASD) have a limited capacity to give correct answers to false-belief tests, corroborating a widespread psychological theory linking autism to a lack of Theory of Mind, which is a capacity to ascribe mental states to other people, for example beliefs. Logical proofs built according to the rules of proof-systems can be used to represent---describe the structure of---mathematical arguments as well as arguments in everyday human practice, and the goal of the project is to analyze and give logical formalizations of psychological tests using a range of modal-logical and hybrid-logical proof-systems, and moreover, investigate empirical consequences of such logical analyses.

Our empirical line of work centers around the notion of recursion, a standard notion from logic (and widely applied in computer science, mathematics, and other fields). Recursion plays a decisive role in second-order false belief tests; a standard measure of second-order Theory of Mind. In these tests, recursion crops up in the form of nested beliefs: Anne believes that Sally thinks that the marble is in the basket. We have carried out a correlation and training study of second-order social reasoning competency in high-functioning children with ASD, the hypothesis being that training in linguistic recursion will improve their social cognition skills, as measured by second-order false-belief tasks. More precisely, we measure the second-order reasoning capacity using a composite score involving four reasoning patterns singled out by our logical analysis. Our study involves 62 Danish-speaking children with ASD. Results are published in Irina Polyanskaya's PhD dissertation.

A number of researchers around the world are attempting to apply logical modeling to problems from cognitive psychology. The project will help this important and exciting interdisciplinary field take root in Denmark. The project is interdisciplinary and combines competences from philosophy, psychology, and logic.