Evaluating Didactic and Exemplar Information: Noninvasive Brain Stimulation Reveals Message-Processing Mechanisms

People in their everyday lives encounter claims about various health, political, and economic issues. These claims are often supported by evidence based on didactic or exemplar information. In the research reported here, we use a noninvasive brain stimulation technique (transcranial Direct Current Stimulation [tDCS]) to examine the cognitive mechanisms underlying people's ability to support or refute claims conveyed by messages that contain didactic or exemplar information. Our results are consistent with the notion that the evaluation of didactic-based evidence engages more deliberative cognitive processes than the evaluation of exemplar information. Our study highlights the utility of tDCS in the study of message processing by demonstrating how it can be used to test the assumptions of message-processing theories.