In a criticism of "homo economicus", a central pillar of classical economic theory according to which humans always behave in a rational way, Nobel Laureate Daniel Kahneman (2002) developed a new model of human decision-making. It consists of two complementary systems: System 1, using individual intuition, and System 2, which carries out deliberate and cognitive reasoning. This model was extended by Pelzmann et al. (2005) to a third system in order to take into account mass-psychological phenomena. System 3 comes into play when humans do not decide based on thoughtful consideration or individual intuition, but rather by orienting themselves to other humans and their actions as a group. Recent advances in brain research, which study the living human brain and its activity patterns, made it possible to tie Kahneman's dual-system concept to specific processes happening in the brain and confirm his theory. Is there neural evidence for System 3, as well? My hypothesis is that brain's mirror neurons are its biological basis. Mirror neurons are nerve cells that are active both when an individual performs a certain action and when he or she observes the same action performed by another. They come into play in situations with social content, and they code synchronous behavior and the common experience of emotional states - the most salient aspects of a mass-psychological phenomenon. In addition, they directly affect human behavior by simulating observed behavior in the brain and triggering a readiness for action. In the default state, a control mechanism inhibits the emotional contagion and the mass-psychological behavior. However, this mechanism is slow, and like muscles it can tire with continuous or intensive use.
When experiencing fear, euphoria or uncertainty, the control mechanism can be weakened, and the decision-making process shifts from System 1 or 2 to System 3, a reaction to others. Insights generated in this dissertation will help us better understand and predict crowd and mass behavior and point the way to future research directions.