Recently many techniques to detect verbal lie have been introduced. Along with this introductions, there have been concerns about emergence of countermeasures that resist verbal lie detection. However, there are few researches testing the effectiveness of countermeasures on statement. Therefore, this study aimed to empirically test the effects of countermeasures on statement characteristics of truth-tellers and liars.
The main hypotheses were: (1) Truth-tellers would state more general and verifiable details than liars. (2) Total amount of general and verifiable details would differ depending on the type of countermeasures: (2-1) Group with research-based countermeasures would state more general and verifiable details than non-provided group. (2-2) Group with practice-based countermeasures would state more general and verifiable details than non-provided group. (2-3) Group with research-based countermeasures would state more general and verifiable details than group with practice-based countermeasures. (3) Effectiveness of countermeasures on statement would differ depending on the veracity.
The independent variables of this study are Veracity and Type of countermeasures. The dependent variables are General and Verifiable details. In a 2(Veracity: truth vs. lie) X 3(Type of countermeasures: non-provided vs. research-based countermeasures vs. practice-based countermeasures) between-subject design study, 120 adults were randomly assigned to each of the six groups.
Truth-tellers were asked to state his own travel experiences since 2019, and liars were asked to state false travel experiences to make interviewer believe that interviewee was telling a truth. Participants were instructed in countermeasures by researcher depending on the conditions. Then, the participants were interviewed about the details of travel with 7 questions. All statements were transcribed and coded by trained graduate students who did not know the condition of the participants for the amount of general and verifiable details.
According to this study, truth-tellers stated significantly more general details and verifiable than liars. And there was also a significant difference in the general and verifiable details depending on the type of countermeasures. However, group with practice-based countermeasures did not significantly state more general and verifiable details than non-provided group. Moreover, there was not a significant difference in effectiveness of countermeasures on statement by veracity. Thus, Hypothesis 1 and 2-3 were adopted, but Hypothesis 2-1, 2-2 and 3 were not adopted.
The implications and limitaions of this study and directions of future research were discussed.