Influence of cathodal and anodal tDCS of the pMFC on choice-induced preference changes
Cognitive dissonance is an inner conflict caused by an inconsistency between a person’s opinions, attitudes, preferences or actions. It motivates people to reduce emerged discomfort by changing their contradicting opinions or preferences to minimize the discrepancy between them (Festinger, 1957). In difficult choices when a person has to choose between two or more equally preferred options this effect decreased preference for rejected option (Brehm, 1956). The neuronal mechanisms of cognitive dissonance are still not clear. Recent neuroimaging studies revealed several brain regions involved in preference changes induced by cognitive dissonance (Izuma et al., 2010; van Veen, Krug, Schooler, & Carter, 2009)actions simply reflect an individual’s preferences, whereas a psychological phenomenon called \» cognitive dissonance \» claims that actions can also create preference. Cognitive dissonance theory states that after making a difficult choice between two equally preferred items, the act of rejecting a favorite item induces an uncomfortable feeling (cognitive dissonance, but here we focus on the posterior medial frontal cortex (pMFC)(Colosio, Shestakova, Nikulin, Blagovechtchenski, & Klucharev, 2017). So as this region is activated during performing tasks with cognitive dissonance non-invasive stimulation of the pMFC can modulate the magnitude of effect and consequential decreasing of preferences (Izuma et al., 2015)preference for the chosen item will increase and preference for the unchosen item will decrease because of the choice made. In other words, we tend to justify or rationalize our past behavior by changing our attitude. This phenomenon of choice-induced preference change has been traditionally explained by cognitive dissonance theory. Choosing something that is disliked or not choosing something that is liked are both cognitively inconsistent and, to reduce this inconsistency, people tend to change their subsequently stated preference in accordance with their past choices. Previously, human neuroimaging studies identified posterior medial frontal cortex (pMFCthrough changing of neurons membrane potential. In our study, for the first time, we used transcranial direct 894 current stimulation (tDCS) of the pMFC to try to decrease and to increase the magnitude of choice-induced preference changes.