Desc: The experiment tests if humans use weak completion or well-founded semantics and how they deal with positive cycles in logic programs. While in a well-founded model atoms involved in positive cycles are false, they are mapped to unknown under the weak completion semantics. In order to determine which semantics is more adequate for human reasoning, it is necessary to investigate which conclusions are typically drawn by human reasoners with respect to cyclic conditionals. The results of the psychological study have been published (Dietz, Hölldobler, & Ragni, 2013).
Classification: Nonmonotonic Reasoning; contradictions; conditional reasoning; well-founded semantics