Date: Friday, 21st November, 2pm Location: E6A room 357 Speaker: Dr. Lee Flax Title: A Logic Based Algebra for Cognitive Modelling Abstract: An algebraic account is given of an approach to cognitive modelling based on the action of cognitive brain components and the activation of neural pathways between them. Frith gives such a model which he uses to explain some signs and symptoms of Schizophrenia. Some of th cognitive components that figure in Frith's model are PERCEPTION, GOALS/PLANS, WILLED INTENTION, ACTION and others. Neural pathways can go from a source component to a target component. Some sources may have pathways that go to several different targets. Frith holds that some of the abnormal behaviour observed in Schizohrenic people is caused by breaks in neural pathways that are unbroken in non-Schizophrenic people. Examples that are examined are: poverty of speech (a person's answers to questions are limited to the minimum number of words necessary), incoherence of speech (grammar is distorted, there are unexpected shifts of topic, there is a lack of logical connection between sentences) and delusions of control (patients experience their actions being controlled by an outside force). We give a Boolean algebra that is able to account for Frith's examples by evaluating certain Boolean expressions. The elements of the algebra are sets of first-order sentences and the partial order relation of the algebra (up to logical equivalence) is first-order entailment.