Why do we lie? Distinguishing between competing lying theories?

Lying is an important human behaviour that has received unprecedented empirical attention in recent years due to a new experimental paradigm in which subjects are incentivised to misreport a die roll for financial gain. Amongst theoretical attempts to explain results, Justified Dishonesty (JD) is a theory with impressive support and a plausible psychological foundation. JD predicts subjects will swap a paid and unpaid roll of a die whenever financially beneficial, as this feels less like lying. However, JD's predictions are virtually identical to a competing economic model. In Dufwenberg & Dufwenberg's (DD) subjects have perceived cheating aversion, incurring a cost of lying that is in proportion to the amount they are perceived to cheat. Current evidence is unable to distinguish between these two distinct mechanisms. Here we show that JD often makes accurate predictions, but is a poor expla- nation. We perform a placebo test, finding that JD is more accurate when it should be irrelevant. Furthermore, we elicit the second (unpaid) roll, strongly rejecting a direct corollary of JD. Our results demonstrate that the role of justifications and desired counterfactuals have been overstated. The simple idea that subjects dislike others perceiving them as liars in proportion to the size of the lie is sufficient to explain patterns of lying behaviour.