Lying for yourself or for others: does confession impacts moral costs?

We will leverage the fact that the World Youth Event 2023 takes place in Lisbon to study moral preferences and actions in a large-scale field experiment combining a short questionnaire with experimental methods. Special considerations are put in place to assure that all responses are anonymized so that it is not possible to identify individuals.
We conduct a field experiment in the World Youth Day Lisbon 2023 in which participants are asked to play the die-under-the-cup paradigm of Fischbacher and Föllmi-Heusi (2013, JEEA) and measure whether they are more likely to tell a selfish lie (about the number of points in the dice) or a an altruistic one, by conducting two different treatments. In one, the benefits from lying are exclusively for the individual that lies and, in another treatment, the gains from lying are for an NGO. We will not know if the respondent lied, but we will compare the distribution of answers with the uniform distribution of an unbiased dice.
The rational individual paradigm assumes that people would lie whenever the benefits of lying exceeds its costs, no matter if the decisions are individual or strategical. This view contrasts with the growing body of experimental evidence that has been showing that not everyone lies (e.g., Gneezy, 2005; Fischbacher and Föllmi-Heusi, 2013), and those that do, do it for different motives besides self-interest, such as altruism or efficiency-seeking. (Erat, and Gneezy, 2012, Chakravarty and Maximiano, working paper). If individuals have moral preferences, when deciding whether to tell the truth or a lie, they will judge the morality of their actions and act accordingly. Our study investigates whether the religious act of confession changes the moral costs of lying. For instance, confessing the sins to a priest and the following act of contraction makes the moral costs of lying more salient and a lie more condemnable?