An Idiographic Paradigm for Research on Cues to Deception: An Urgent Proposal

We introduce a novel individual-focused paradigm to the scientific study of deception cues. Past research on deception cues compares the behavior of truth tellers and liars at the group level, suitable for answering the question how the behavior of truth tellers and liars differ on average. However, unless two conditions are met, that the statistical models do not vary (i) across individuals or (ii) across occasions in time, group-level findings cannot accurately describe the behavior of individuals. We present theoretical arguments and empirical data that show that these conditions are unlikely to be met for deception cues. In other words, the current paradigm can say how truthful and deceptive messages differ on average, but it cannot describe how particular individuals will behave when they are lying or telling the truth. As such, in order to draw meaningful conclusions about the individual, the field needs a wholly different research paradigm, based on repeated measures designs. We outline a proposal for such an idiographic research agenda. Without the development of an idiographic approach to research on deception cues, fundamental questions in deception research will remain unanswered, theories of deception will be incomplete, and practitioners, whose focus is always on the individual case, will continue to find limited value in traditional research conducted at the group-level.