Oculomotor behavior tracks the effect of ideological priming on deception.

The decision to lie to another person involves a conflict between one's own and others' interest. Political ideology may foster self-promoting or self-transcending values and thus may balance or fuel self vs. other related conflicts. Here, we explored in politically non-aligned participants whether oculomotor behavior may index the influence on moral decision-making of prime stimuli related to left and right-wing ideologies. We presented pictures of Italian politicians and ideological words in a paradigm where participants could lie to opponents with high vs. low socio-economic status to obtain a monetary reward. Results show that left-wing words decreased self-gain lies and increased other-gain ones. Oculomotor behavior revealed that gazing longer at politicians' pictures led participants to look longer at opponent's status-related information than at game's outcome-related information before the decision. This, in turn, caused participants to lie less to low status opponents. Moreover, after lying, participants averted their gaze from high status opponents and maintained it towards low status ones. Our results offer novel evidence that ideological priming influences moral decision-making and suggest that oculomotor behavior may provide crucial insights on how this process takes place.