Qualitative Probabilistic Inference with Default Inheritance

There are numerous formal systems that allow inference of new con- ditionals based on a conditional knowledge base. Many of these systems have been analysed theoretically and some have been tested against human reasoning in psychological studies, but experiments evaluating the performance of such systems are rare. In this article, we extend the experiments in (19) in order to evaluate the inferential properties of c-representations in comparison to the well-known Sys- tems P and Z. Since it is known that System Z and c-representations mainly differ in the sorts of inheritance inferences they allow, we discuss subclass inheritance and present experimental data for this type of inference in particular.