Assessing lying about opinions through extending the devil's advocate interview protocol with a same example statement

The devil's advocate interview protocol is a method to detect lies about opinions. Interviewees are asked to provide reasons that support their opinion (eliciting opinion request) and reasons that oppose their opinion (devil's advocate request). Truth tellers are expected to be more eloquent, passionate and less predictable than lie tellers in responding to the eliciting opinion request. The difference in eloquence, passion and predictability between the two requests is expected to be more pronounced in truth tellers than in lie tellers. In the present experiment we examined whether adding a same example statement to the protocol would increase the ability to distinguish between truth tellers and lie tellers. In the same example statement condition, participants watched an example in which someone eloquently expressed their opinion about the same topic and opinion that the interviewee was going to discuss in the interview. We predicted the same example model statement to enhance the efficacy of the devil's advocate interview protocol. A total of 171 truth tellers and lie tellers expressed their true opinions or false opinions about societal issues (e.g. covid vaccinations). Half of them watched a same opinion statement. The hypotheses were supported for eloquence and passion.