The relative impact of violation type and lie severity on judgments of message deceitfulness

Abstract

This paper is part of a larger program of research assessing variables that underlie quantitative deceptiveness ratings. Several recent theoretical approaches, including Information Manipulation Theory (IMT), propose that deceptive messages are best understood as varying along two or more dimensions. At the same time, researchers have increasingly moved from dichotomous deception judgments to continuous deception ratings. This paper questions the validity of scaling degrees of deceptiveness along a single dimension, and argues that gradations in perceived deceptiveness reflect both the type of information manipulated and the severity of the consequences of the deception. This reasoning was tested with alxl experiment (N = 236) in which both the type of information manipulated and the severity of the consequences were systematically varied. As predicted, the results suggest that false messages (i.e., quality violations) are rated as more deceptive than lies of omission (i.e., quantity violations) when lie severity is low, but this difference diminishes as lie severity increases. In other words, false messages were rated as deceptive regardless of severity, but messages omitting information were rated as deceptive as false messages only when the consequences were serious. The implications for measuring deception are discussed.