Reasoning with Exceptions: An Event-related Brain Potentials Study

摘要

Defeasible inferences are inferences that can be revised in thenlight of new information. Although defeasible inferences are pervasivenin everyday communication, little is known about how andnwhen they are processed by the brain. This study examined thenelectrophysiological signature of defeasible reasoning using anmodified version of the suppression task. Participants were presentednwith conditional inferences (of the type “if p, then q; p,ntherefore q”) that were preceded by a congruent or a disablingncontext. The disabling context contained a possible exceptionnor precondition that prevented people from drawing the conclusion.nAcceptability of the conclusion was indeed lower in the disablingncondition compared to the congruent condition. Further,nwe found a large sustained negativity at the conclusion of the disablingncondition relative to the congruent condition,which startednaround 250msec and was persistent throughout the entire epoch.nPossible accounts for the observed effect are discussed